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The aims of the training package

To prepare an engineer to understand heat pump technology
To be able to undertake safe installation and maintenance of heat pumps
To prepare all for assessment

Scope

Heat pumps up to 45 kW
Systems not to exceed 70 kW heat output

This qualification/training does not include the repair or replacement of refrigeration components or the safe handling of the associated gas (F-gas)

Exclusions- this training does not include the following: Electrical work, detailed heat loss calculations, work on components covered by F-Gas and other works associated with heat pump installations e.g. Plumbing and building

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Design

Design can be achieved by completing the MCS ASHP calculator and following the recommendations.

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Design

Another useful tool for designing the heat pump set up can be found using this tool:

Heat-Loss JS Tool

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Let us look at the types and how they function

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To do-Component Descriptors

A safety device that is mounted just before the compressor and is designed to detect if the pressure becomes too low
A safety device that is mounted just after the compressor and is designed to detect if the pressure becomes too high
This component ensures that any moisture or particles that may be within the refrigerant circuit is dealt with and does not affect the operation of the heat pump
This component is the heart of the heat pump and is the motiver force that pushes the refrigerant around the circuit
This component detects the temperature of the refrigerant circuit and allows the expansion valve to alter the pressure accordingly
A component that allows the refrigerant to change from a gaseous to a liquid state by allowing it to transfer its latent heat from the refrigerant to the emitter circuit without coming into direct contact with it
This component automatically allows the refrigeration to alter direction to aid in the defrost cycle

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To do-Component Descriptors (look at the descriptors and match with component)

A safety device that is mounted just before the compressor and is designed to detect if the pressure becomes too low
A safety device that is mounted just after the compressor and is designed to detect if the pressure becomes too high
This component ensures that any moisture or particles that may be within the refrigerant circuit is dealt with and does not affect the operation of the heat pump
This component is the heart of the heat pump and is the motiver force that pushes the refrigerant around the circuit
This component detects the temperature of the refrigerant circuit and allows the expansion valve to alter the pressure accordingly
A component that allows the refrigerant to change from a gaseous to a liquid state by allowing it to transfer its latent heat from the refrigerant to the emitter circuit without coming into direct contact with it
This component automatically allows the refrigeration to alter direction to aid in the defrost cycle

Four way valve

Condenser

Expansion valve phial

Compressor

Dryer receiver

High pressure switch

Low pressure switch

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To do-Component Descriptors

A safety device that is mounted just before the compressor and is designed to detect if the pressure becomes too low
A safety device that is mounted just after the compressor and is designed to detect if the pressure becomes too high
This component ensures that any moisture or particles that may be within the refrigerant circuit is dealt with and does not affect the operation of the heat pump
This component is the heart of the heat pump and is the motiver force that pushes the refrigerant around the circuit
This component detects the temperature of the refrigerant circuit and allows the expansion valve to alter the pressure accordingly
A component that allows the refrigerant to change from a gaseous to a liquid state by allowing it to transfer its latent heat from the refrigerant to the emitter circuit without coming into direct contact with it
This component automatically allows the refrigeration to alter direction to aid in the defrost cycle

LPS
HPS
Dryer receiver
Compressor
Expansion vessel phial
Condenser
Four way valve

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So what exactly is a heat pump

Transfers the sun's solar energy stored in the ground, water or air into a heating or hot water circuit
Uses a refrigeration circuit as a method to transfer heat

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UK solar radiation warming ground and air

Variations in solar radiation across the UK

South - 1200 kWhrs/㎡/year

North - 900 kWhrs/㎡/year

(figures are average)

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Before we begin

What is the start point for every good heat pump installation?

An accurate heat-loss calculation
Correctly sized emitters (radiators etc.)
Fully integrated heating controls

It is not a simple exchange from a gas or oil boiler

MCS

Likely that access grants will require

MCS Certification:

“Give people confidence in low carbon energy technology”

MCS publishes a series of standards and documents. These standards are industry led and key to ensuring quality.

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MCS documents

MIS 3005

Is split into two documents.

MIS 3005 I - the heat pump standard (Installation)

MIS 3005 D - the heat pump standard (Design)

There are a number of useful and supporting documents including guidance and calculation tools that can be found at:

https://mcscertified.com/

Key facts:

Contracts have to be set out what the expected performance of the system will be before the contract is signed
The MCS contractor has to hold the contract with the consumer
Systems have to be designed in accordance with the relevant MCS standard
Systems cannot just be ‘signed off’ by an MCS contractor
Any deviation will mean the certificate isn’t valid and potentially huge financial consequences

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Project planning-Health and Safety/Standards

Project planning should take into account at least the following points

Start dates
End dates
Access required
Loss of, or reduction of certain services during the installation process
Movement of large and heavy units into their desired location
H&S requirements
On-going access requirements for maintenance and servicing
Specific site survey information
Note any damage that is evident at the site )to avoid any possible future disputes)

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Health and Safety

Refrigerant handling-

This training does not cover any work involving the refrigerant circuit (e.g. and F-Gas or CO2)
Any person accessing the refrigerant for filling, evacuating, testing (including leak testing) or maintenance must be competent to do so.

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Health and Safety-refrigerant handling categories

Engineers fall into 4 different categories and dependant on the category will vary what work they can do;

Category I
Category II
Category III
Category IV

Category I: engineers can undertake all types of work with refrigerants

Category I = complete
Category II = everything up to 3kg
Category III = de-commission
Category IV = stop leaks

Engineers undertaking this specialist work should have received prior training as the gases by their nature are highly FLAMMABLE

Engineers should always be aware of the type of system they are working on and the refrigerant being used

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Health and Safety-risk and COSHH assessment

Risk	Cause
Electrocution	Failing to safely isolate the supply circuit
Burns	Soldering pipework
Toxic poisoning	Ingestion of antifreeze/Biocide
Personal injury	Moving a heat pump into place - some units can be over 100kg

Remember the electrical isolation should be adjacent to the unit and be on it’s own circuit

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Health and Safety-risk and COSHH assessment

Remember the electrical isolation should be adjacent to the unit and be on it’s own circuit

Risk	Cause	Mitigation
Electrocution	Failing to safely isolate the supply circuit	Ensure circuit is safely isolated
Burns	Soldering pipework	Allow adequate cooling time
Toxic poisoning	Ingestion of antifreeze/Biocide	Care when handling antifreeze/biocide
Personal injury	Moving a heat pump into place - some units can be over 100kg	Risk assessment carried out before unit is moved into place

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Health and Safety-risk and COSHH assessment

INDG163

Risk & COSHH assessments are required
Assessments can be informal where suitable
They help you conform with the law
Help you focus on the risks that really matter - the ones that cause real harm

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Health and Safety-Method statement

Used in conjunction with a risk assessment
Having assessed all the risks method statements can be useful to detail how a particular process/installation will be carried out safely
May be required by the principal contractor
Written to ensure all control measures are adhered to when planning methods and tasks

On the right is an example Method Statement for the installation of an ASHP.

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Standards and Best Practice

BSEN 12831 - Heat loss calculations
BSEN 15450 - Design of heat pumps
BSEN 14511 - Air conditioners, liquid chilling packages and heat pumps with electrically driven compressors for space heating and cooling
BSEN 14825 - Air conditioners, liquid chilling packages and heat pumps with electrically driven compressors for space heating and cooling. Testing and rating at part load conditions and calculation of seasonal performance
CIBSE Domestic Heating Design Guide
HSE ACoP and L8 to Legionella prevention (not statutory)

MIS - 3005
MCS 020 Noise calculations for heat pumps
DNO connection guidance
Domestic Building Services compliance guide
Chartered Institute of Building Services Engineers
(CIBSE) Guide A & Domestic Heating Design Guide
Building Regulations 2010 (as amended) and devolved equivalents
Water Supply (water fittings) Regulations 1999

DNO - (Distribution Network Operators (DNOs) are licensed companies that own and operate the network of cables, transformers and towers that bring electricity from the national transmission network to businesses and homes.) Supplier of electric.

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Standards and Best Practice

Key Approved Documents

Part A - Structure
Part B - Fire Safety
Part C - Moisture
Part L - Energy Efficiency )includes energy conservation and commissioning)

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Standards and Best Practice

F - Gas Regulations

An F - Gas registered engineer must be used when a refrigerant circuit is broken or made
For example-
Assembly and charging on-site
Checking for F-Gas leaks
Recovering F-Gas from the refrigerant circuit

The F - Gas Regulation bans the use of F Gases in certain applications and sets requirements for leak checks, leakage repairs and recovery of used gas. In addition, the F gas Regulation requires that all technicians handling

F - Gases must be trained in their safe use and certified.

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ERP - Overview

The ERP is always supplied by the manufacturer of a product. In our case the product would be an ASHP.

ERP stands for Energy Related Products
Mandatory labelling about consumption of energy and noise levels
All heat pumps <70 kW must display a label similar to TV’s, refrigerators, washing machines and gas boilers.
G is the least efficient, A+++ the most efficient, (over a full year)

ERP - Overview

Manufacturers and installers are required to provide product and package labels respectively.
Map includes 3 climate zones and a power level for each zone (average)
Different labels for emitter types (radiator 55℃ underfloor 35℃)

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ERP - Overview

All ERP labels are based on Fiches

Fiche gives data from standard test conditions

Three climate conditions. Cold, Average and Warm

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ERP - Overview

Package label for the whole system
Includes controls and other inputs (solar heating/auxiliary boilers)
Most manufacturers provide controls so package label included
Where DHW is included, typically class A
DHW indicated by tap, heating by radiator

Hot water will never be above A rating due to the low temperature that can be achieved on an ERP.

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Types of Heat Pumps

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Types of Heat pump

Monobloc

Bi-Bloc (split)

Exhaust Air

Ground Source

Water Source

Monobloc

Bi-bloc

Exhaust

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Types of Heat pump

Monobloc-

The refrigerant is wholly contained within the outdoor unit (hermetically sealed) and comes factory charged, assembled and tested.

A monobloc system has all the components in a single outdoor unit, with pipes carrying water to the central heating system and a hot water cylinder inside your home.

Monobloc

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Types of Heat pump

Bi-bloc-

Bi-bloc split, the refrigerant between indoor and outdoor units will have to be connected, charged and commissioned on-site (likely to require F-Gas registered personnel).

The absorber is the outdoor unit and indoor unit is the hydro box wall mounted.

Bi-bloc

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Types of Heat pump

Exhaust-

Heat recovery based on exhaust air, combining ventilation with air exchange to provide heating & hot water

Removes stale air
Supplies fresh air
Prevents moisture and mould growth

Exhaust

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Types of Heat pump

Types of exhaust air

Exhaust Air to Water

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Types of Heat pump

Ground/Water-

A ground source heat pump, sometimes referred to as a ground-to-water heat pump, transfers heat from the ground outside your home to heat your radiators or underfloor heating. It can also heat water stored in a hot water cylinder for your hot taps and showers.

Water source heat pumps are often more efficient than ground and air source devices. This is because heat transfers better in water, while water temperatures are generally more stable throughout the year (between 7 and 12 degrees on average), which is higher than the average air and ground temperature in winter

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Monovalent & Bivalent

Monovalent - heat load of building met solely by the heat pump (no additional energy)

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Monovalent & Bivalent

Bivalent - part of the heat load of the building is met by the heat pump the remainder met by an additional energy source (potentially electric immersion)

Hybrid (also called Bivalent)
Heat pumps provide 100% of the demand to a given setpoint and then works with a gas or oil boiler to provide the remaining load.
Can be retrofitted to existing or for new systems.
System can be with any type of heat pump.

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Air source heat pump

Uses ambient outdoor air as the energy source
Can be used with temperatures as low as -25℃
Advantageous over ground source where access or cost is a consideration
Customer concerns can include:
-Noise pollution
-Unit sited externally (aesthetics)

Notes- Ambient meaning (Ambient describes some pervasive quality of the surrounding environment, like the ambient lighting in a movie theater, or the ambient temperature of a room. Most times when you're hearing silence, you're hearing some ambient noises too, like the hum of a refrigerator or the whistle of a breeze).

Notes continued- Aesthetics meaning (Beauty is one of the main subjects of aesthetics, together with art and taste. Many of its definitions include the idea that an object is beautiful if perceiving it is accompanied by aesthetic pleasure. Among the examples of beautiful objects are landscapes, sunsets, humans and works of art).

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Heat pump suitability

Factors to consider:

Room by room heat loss

Emitter circuit (type)

Suitable outdoor location

Indoor location (larger cylinder etc.)

Notification to the District Network Operator (DNO)

Cost of Installation

MCS calculator

Myson radiator

Think (energy saving trust)

Packages

Find your DNO

Costing estimates

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Refrigeration cycle

Fluid principles

Water changes from a solid to a liquid at around 0℃ and from a liquid to a gas at around 100℃ under normal atmospheric pressure
At phase/state change between a liquid and a gas water will require (and therefore absorb) over 5 times as much energy without a rise in temperature. This is called latent heat.

Fluid principles

When under pressure of around 3 bar water will convert to a gas at around 144℃
At phase change between a liquid and a gas the water will still require (and therefore absorb) over 5 times as much energy without a rise in temperature.

Increase the pressure = Increase the temperature

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Refrigeration cycle

Fluid principles

When subjected to low pressure of around 0.5 bar water will convert to a gas at around 80℃
At phase change between liquid and a gas the water will still require (and therefore absorb) over 5 times as much energy without a rise in temperature.

Fluid principles

Refrigerant acts the same as water, absorbing the heat (energy) when evaporating
Temperature is lower than that of water. Principle is the same
Refrigerants used in heat pumps boil well below 0℃ and would be in a gaseous state at normal atmospheric pressure

E.G. R410a boils at -48.5℃

Lower the pressure = Lower the temperature

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Vapour Compression Cycle

Think back and look at your notes, which way is the cycle going in?

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Principles of Operation

1st Evaporator

Low pressure liquid enters
Liquid evaporates/boils absorbing energy
Low pressure gas leaves and enters the compressor
ASHP exchanges heat through the “evaporator’ coil
GSHP exchanges heat through the plate heat exchanger

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Principles of Operation

2nd Compressor (rotary)

There are two main types of compressor currently in use; fixed speed and inverter driven (this is the most common now in use)

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Principles of Operation

3rd Condenser

Plate type heat exchanger
High pressure HOT GAS enters from compressor
Heat energy transfers to cooler emitter circuit fluid
Refrigerant gas condenses
High pressure LIQUID leaves

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Principles of Operation

4th Expansion valve

Expansion valve
High pressure liquid from condenser
Causes pressure to fail
Low pressure liquid leaves

Electronic expansion valve which uses thermistors as temperature sensors.

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Principles of Operation

The expansion valve controls the flow of the refrigerant gas from the condenser to the evaporator. As the refrigerant gas flows through the expansion valve its pressure is reduced. When the refrigerant gas was compressed its temperature increased, so conversely as its pressure is reduced its temperature falls

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System components

All heat pumps require the following

Heat pump unit, including a heat transfer fluid
Evaporator
Condenser
Emitter
Controls, both for the heat pump and heating/domestic hot water. A modern air source heat pump system can typically be controlled from a central control panel. We’re able to control all the heating and hot water settings for our home from the control panel shown below.

(refrigerant)
(absorber)
(to exchange heat to emitter circuit)
(radiator/under floor etc.)

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Indoor parts of an ASHP installation can include

Air handler
Buffer tank
Expansion vessel
Hot water tank
Underfloor heating
Radiators
Central control panel
Thermostats
Internal pipework
Expansion valve

Air handlers can contain the indoor coil, where a fan blows air over the coil inside the unit to release heat
As part of an air to water heat pump system, a buffer vessel and expansion tank(s) can be used to help transfer the heat from the refrigerant to the water flowing around the home as part of the central heating system.

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System components collectors

ASHP

Collection is via the evaporator unit
Consists of large finned radiator system
Extract energy from outside ambient air

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System components collectors

GSHP

Collection is via the plate heat exchanger
Extracts energy from the ground or water etc.

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Controlling the unit/system

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COP & SCoP

CoP

Expression of heat pump efficiency at a fixed input and output

1 kWh electrical energy to produce 3 - 4 kWh heat = CoP 3.0 to 4.0

Influences
Temperature of heating primary circuit serving the heating and hot water
Temperature available from the ambient air for ASHP or ground temperature for GSHP
Manufacturing components (not in your control)
A good CoP is critical to ensure an efficient system

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COP & SCoP

CoP

CoP is measured under controlled conditions:

ASHP

Commonly air temperature of 7℃ and flow temperature of 35℃
Abbreviated to A7/W35 (air/water)

So in this example above what would the CoP be?

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COP & SCoP

CoP

CoP is measured under controlled conditions:

Exhaust air to water

Commonly air temperature of 20℃ and flow temperature of 35℃

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COP & SCoP

CoP

CoP is measured under controlled conditions:

GSHP

Commonly heat transfer fluid of 0℃ and flow temperature of 35℃ for GSHP
Abbreviated to B0/W35
Thermal output )kW) rating of the unit also uses these standard conditions (more on this later)

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CoP

Compressor works harder to get high temperatures

Uses disproportionately more electrical energy to do so

More electrical energy = lower CoP

A7/W35 CoP = 3.8

A7/W50 CoP = 3.0

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CoP considerations

CoP values should always be compared like for like, for example;

Key factors to consider when comparing CoP values

Accurate comparison across manufacturers
What was the air or ground temperature when CoP was measured?
What was the flow temperature from the heat pump?

CoP values for ASHP

Usually provided with two measured values for CoP

Water at 35℃ or Water at 55℃

Typically based on 7℃ air temperature
Expressed as A7/W35 or A7/W55

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SCoP - seasonal coefficient of performance

In general SCoP focuses on the device in theoretical ‘standard’ situation which is NOT project specific

It is the expression of heat pump overall operating efficiency

Ratio between all electrical energy used and heat delivered over a “typical” year

The SCoP can dramatically alter the performance estimate

The performance estimate calculation is unrelated to sizing the heat pump

The two separate requirements should not be confused

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SCoP - seasonal coefficient of performance

MCS Heat Pump System Performance Estimate

MCS hpspe

Open spreadsheet via link

Enter values as required

Calculations will be completed automatically

Overall system efficiency

“System efficiency”

Takes into account all parts of the system including the emitters, controls and heat pump itself. The following needs to be considered:

Parasitic losses
Non parasitic losses

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Refrigeration capacity

Refrigeration capacity =

Cooling of refrigeration circuit - compressor energy

Example:

Heat pump output = 11.8 kW

Electrical input to compressor = 2.66 kW

Refrigeration capacity = 11.8 - 2.66 = 9.1 kW

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Heat distribution

Room by room heat loss calculations are ESSENTIAL
Pre contract site assessment is essential
Ideally buildings should be well insulated allowing heat pumps to run at low temperatures

It is vital that an accurate heat loss calculation is carried out

Do not rely on rules of thumb!
It’s okay for rough estimate/budget purposes but NOT good enough for system design
BS EN 12831 compliant ONLY software which will perform a room by room heat loss calculation

See slide 003 for the MCS calculator

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Heat distribution

It is vital that an accurate heat loss calculation is carried out

Heat loss calculations shall be based on the internal and external temperatures recommended in MIS 3005 which is based on CIBSE guidance
Geographical location can make a BIG difference (North v South) as well as height above sea level
For LARGE projects, many manufacturers may calculate heat losses on your behalf

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Heat emitter circuit

Vital that an accurate heat loss calculation is carried out

The type of heat emitters selected is important to ensure that the optimum 𝚫t is achieved for the heat pump on the primary circuit flow and return (typically 5℃)
The choice is usually one of three;
Under floor (buried pipework)
Radiator
Fan convectors

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Heat emitter circuit

Multiple zones

The heat pump will have to generate temperature required for the zone with the highest flow temperature requirement (this will determine the efficiency of the heat pump)

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Heat emitter circuit-name some advantages & disadvantages

Radiators

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Heat emitter circuit-name some advantages & disadvantages

Radiators advantages

Easy fit
Cheap
Understood and accepted by public

Radiators disadvantages

Larger than usual size due to lower temp
Wall space
Corrosion

It could be possible to “swap’ radiators between rooms to get the best match without having to replace all the radiators.

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Heat emitter circuit-name some advantages & disadvantages

Underfloor

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Heat emitter circuit-name some advantages & disadvantages

Underfloor advantages

Discrete installation
Well matched to heat pumps
All round heat
Easy control
Limited corrosion
Saves wall space

Underfloor disadvantages

Tricky for retrofit
Customer education
Requires supervised construction
More expensive installation cost

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Heat emitter circuit-name some advantages & disadvantages

Forced air advantages

Semi discrete
Well matched to heat pumps
Rapid response
Easy control
Limited corrosion

Forced air disadvantages

Cost
Can have “commercial” look
Noise

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Heating water volume

The minimum water volume of the heating system must be secured at all times to prevent heat pump high pressure faults.
A high-pressure alarm is caused by a poor flow rate on the waterside of the heat exchanger in the heat pump; this then leads to the system overheating and shutting down. The most likely causes for this alarm are: A lack of system water – 1 bar of water pressure is required within the heating system.

Different volumes that are required , are dependant upon the heat pump model being installed

Ensuring minimum system volume is crucial to ensure trouble free running

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Heating water volume

Manufacturers data will provide information of minimum system volume
If the system as a whole can provide the required volume
Consider if only one zone is calling for heat!

Flow rates are crucial to the heat pumps operation

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Heating water volume

However whatever the minimum thermal output is for the heat pump

The system volume must be able to cater for this to avoid overpressure faults
Where required a buffer tank/volumiser is required to help ensure the minimum volume

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Heating water volume

Buffer tank or volumiser?

A volumiser will only have 2 tappings and sits in series with the flow and return heat pump primary pipework
A buffer tank will have 3 or more tappings (usually 4) and is designed to provide a hydraulic break between circuits with separate circulators

A buffer tank can also add volume to the system so can fulfill the role of a volumiser

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Heating water volume

Sizing of buffer tanks is based on two factors, one is the volume of the water to be heated and the other is the flow rate that needs to be maintained. In reality the deciding factor will be the volume of water to be heated. This involves a calculation to be undertaken as follows;

V= tank volume required

Q= heat load

t= minimum gap between heat pump starts (in seconds)

𝚫c= decrease in tank temperature during time

𝚫c for radiator circuits can be taken as 10℃

𝚫c for fan coil and underfloor heating can be taken as 5℃

V = Q x t

4.2 x 𝚫c

Q x t divided by 4.2 x 𝚫c

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Heating water volume

Practical application

We have a heating load of 8.4kW, the maximum number of starts in a given hour is three as given by the district network operator, and the emitter is an underfloor heating system.

So how do we begin to work this out?

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Heating water volume

Practical application

We have a heating load of 8.4kW, the maximum number of starts in a given hour is three as given by the district network operator, and the emitter is an underfloor heating system.

V = to be calculated

Q= 8.4

t= (20 x 60) = 1200 (3 starts per hour)

𝚫c= 5℃

So how do we begin to work this out?

V= 8.4 x 1200

Divided by 4.2 x 5 = ??????

Multiply 4.2 x 5 first, then multiply the 8.4 x 1200 and divide by your first answer.

Have a go what do you get?

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Heating water volume

Practical application

We have a heating load of 8.4kW, the maximum number of starts in a given hour is three as given by the district network operator, and the emitter is an underfloor heating system.

V = to be calculated

Q= 8.4

t= (20 x 60) = 1200 (3 starts per hour)

𝚫c= 5℃

So how do we begin to work this out?

V= 8.4 x 1200

Divided by 4.2 x 5 = 480 litres

Multiply 4.2 x 5 first, then multiply the 8.4 x 1200 and divide by your first answer.

Have a go what do you get?

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Heating water volume

What is a volumiser?

A thermal store with high insulation and low heat loss characteristics
Sized in accordance with the minimum heating water flow rate of the heat pump

NOTE - No internal coil/heat exchanger

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Heating water volume

What is a volumiser?

Volumiser 2 pipe arrangement

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Heating water volume

What is a volumiser?

Volumiser 3 pipe arrangement

Reduces mixing down of return water temperature

May require extra circulator to achieve it

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Heating water volume

What is a volumiser?

Volumiser 4 pipe arrangement

Ideal for larger systems in continuous operation

and fixed temperatures with one or more

secondary circuits operating at varying flow rates

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Heating water volume

What is a volumiser?

Buffer (volumiser) arrangements - Bypass

Setting bypass too high =

heat pumps minimum flow rate

cannot be achieved as circuits close down

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Heating water volume

What is a volumiser?

Buffer (volumiser) arrangements - Bypass

Setting bypass too low =

Short circuit back to the heat pumps = possible fault under a high pressure alarm

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Domestic hot water cylinder selection guide

MCS guide on cylinder selection

DHW from heat pumps will usually be stored at a lower temperature (better efficiency)
Lower temperature of DHW means larger storage volume required

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Domestic hot water cylinder selection guide

MCS guide on cylinder selection

DHW cylinder sizing is NEVER an exact science however, 45 litres per occupant can be used as a starting point
Measures to prevent scalding such as a TMV2 or TMV3 valve are still required as most stores have immersions fitted

These are TMV2 and TMV3. The main difference between the two comes down to water pressure and speed of operation. TMV2 is primarily used in domestic environments and works with water pressure from 0.1 – 5 bar. TMV3 is used in commercial settings and works with water pressure up to 10 bar

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Domestic hot water cylinder selection

An accurate assessment of the hot water requirement is vital
Adjusted for stored water temperatures (To improve energy efficiency, it is very important to keep the water temperature within the heat pump to the lowest values possible. However, most cylinders are maintained at over 50°C all the time, and often heated to 60°C weekly for legionella protection (often with assistance of a direct electric immersion element)
Allowance for cylinder recovery rate to be included (As a general rule of thumb, most cylinders can achieve a reheat time of around 20 minutes (laboratory), and adjusted recovery to accommodate the variables of ‘real life’ in a typical house, after a bath fill for example, tends to be around 25 to 30 minutes)

BS EN 806 pt 1-5 (BS8558)

Specification for design, installation, testing and maintenance of services supplying for domestic use

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Domestic hot water cylinder types

Packaged unit

Factory assembled and easy integration with corresponding

HP manufacturers

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Domestic hot water cylinder types

Tank in tank
One tank inside another
Inner tank is domestic hot water
Outer tank is primary heating water
Wall of the inner tank acts as the heat exchanger

absorbing heat from the outer tank

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Domestic hot water cylinder types

Domestic hot water fed from gas or oil system normally stored at 60-65℃.

Most heat pumps can only lift stored water to around

45-50℃ (specific to heat pumps).

If sterilisation is required usually achieved by an immersion

heater.

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Prevention of bacterial growth (legionella bacteria)

Legionnaires disease: a severe form of pneumonia caused by:

Higher than normal concentrations of legionella bacteria
Inhaling into the lung via an aerosol spray
Particular risk to those with low immunity e.g. elderly or infirm

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Pasteurisation

MIS 3005 requires a means to prevent bacterial growth (including legionella)

A risk assessment shall be conducted to determine what level (if any) of protection is required

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MCS heat pump selection

For MCS purposes all heat pumps shall be selected to provide 100% of the required design space heating power requirement at the selected ambient temperature.

Data shall be provided to give evidence that the heat pump can meet the above demand WITHOUT the inclusion of supplementary electric heating.

This does not rule out Bivalent or Bivalent Hybrid systems.

Things to consider

Determine the building heat load
Can this be met 100% by a heat pump?
Bivalent/Monovalent
Determine system configuration
Select heat pump for system requirements
Determine heat pump output of ambient design temperature
Determine supplementary heating if required
Determine heat pump systems flow temperature

Scenario for a heat pump for you to do on the next slide

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MCS heat pump selection

Things to consider

Determine the building heat load
Can this be met 100% by a heat pump?
Bivalent/Monovalent
Determine system configuration
Select heat pump for system requirements
Determine heat pump output of ambient design temperature
Determine supplementary heating if required
Determine heat pump systems flow temperature

Drawing required for your scenario

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MCS heat pump selection

What will you look at firstly when advising and designing the system for the family of 5 who live in this property?
Which documentation will you use to assist you in your survey/calculations?
How will you present your findings to the client?

Drawing required for your scenario

On a sheet of paper identify the documentation required, list the rooms and sizes, heat loss calculations and how you will present to client. Include the heat pump size, the size of the cylinder/volumiser.

Useful resource for heat loss

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MCS heat pump selection

Example of a heat loss calculation give us the following results:

	Heat loss (kW)
Ground floor	7.03 kW
First floor	5.33 kW
Total heating	12.36 kW
3 occupants DHW: 0.2 kW/person	0.6 kW
Total heat pump requirement	12.96 kW

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MCS heat pump selection

One of the most common errors made by installers and designers alike

Output reduces with outside temperature and increased flow temperature
A “13 kW” heat pump will not give the required output at the design temperature of -3℃ if you did not look at the chart to the left in MIS 3005
Adjusting for ambient air temperature and accurate room by room heat losses are critical

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Site location noise

Planning and permitted development

ASHP fans do have a residual noise
Consumer needs to be made aware
Planning may be required if certain conditions are not met (MCS 020)

GSHP can be similar with noise from the compressor, although usually mounted inside so planning not an issue.

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Site location noise

Noise from ASHP or GSHP vibration can be reduced with:

Flexible hoses (reducing stress on pipework and noise transmission)
Rubber mounts on feet
Feet bolted to large rubber blocks

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Site location noise - pipe through walls

Heat pumps differ from conventional heating systems as they will have collector loop, flow and return or refrigeration pipework that goes through the external wall.

Provision shall be made to ensure:
Movement
Protection against freezing (fluid or movement)
Water tightness of the building
Insulation incorporating rodent and UV protection

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Site location noise - pipe through walls

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Site location - refrigeration flammability

Some refrigerants (e.g R290 which is propane) can be highly flammable, so consider:

Location to:
Drains
Doors
Windows
Sources of ignition

Using R290 means heat pumps can achieve a high flow temperature of up to 75°C if required. Setting the flow to this maximum temperature for hot water means that an electric immersion heater for legionella protection isn't necessary.

R290 is flammable, so extra care must be taken when handling and using it. There is a risk of explosion if it leaks and comes into contact with an ignition source.

It has high pressure, so refrigeration systems using R290 must be designed accordingly to manage this pressure safely.

Always consult MI’s for siting of the unit for noise and refrigeration risk

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Fluids in collector and primary circuit

Antifreeze
Biocide

As with any heating system the system should be fully flushed with clean water prior to any chemicals being added. This will ensure that there are no contaminants that may affect the chemicals. Thermablend

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Antifreeze protection

Mono Ethylene glycol

Most commonly used type
Moderately toxic
Hazardous to health
Good thermal properties

Mono propylene glycol

Non toxic
Can be used in sensitive areas
Less environmental impact than Ethylene
More viscose than ethylene

All systems must be designed to minimise the risk of introducing harmful substances into the environment

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Antifreeze protection

All fluids require careful mixing to ensure

A constant solution
Correct ratio
Protection against freezing
Constant viscosity

Checked using a refractometer

Refractometer

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Antifreeze protection

All fluids require careful mixing to ensure

A constant solution
Correct ratio
Protection against freezing
Constant viscosity

Checked using a refractometer

Refractometer

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Antifreeze protection

Ethylene glycol concentration

Look at the graph on the right of the screen;

If you had a 20% ethylene mix what temperature would it protect to?
If you had a 40% ethylene mix what temperature would it protect to?
If you had 50% ethylene mix what temperature would it protect to?

Remember the unit we are looking at is deg C

If you have too much concentration this will increase viscosity, pump size and power consumption. Why is this?

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Antifreeze protection

Frost protection

All component exposed to low temperatures require protection:

Insulation

Good quality
UV resistant
Suitable for external use

But not sufficient protection on its own

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Antifreeze protection

Biocide

Low F&R temperatures in the primary circuit
Can lead to excessive biological growth
This leads to deposits (sludge) building up
Biocides can help limit this growth

Combine Biocide & Antifreeze

Some products on the market come with biocide and antifreeze pre-mixed
Simple one stop solution
Meets all requirements
No calculations required
Requires “filling station”

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Electrical

Circuit sizing and DNO approval

Installation of a suitable supply should always be carried out by a competent electrician.

Heat pumps require a device (usually CB (circuit breaker) to protect the circuit)
Sizing the CB is important to avoid nuisance tripping out
When ASHP units start they can draw 2-3 times their usual power for a very short period (if not inverter driven)
Inverter heat pumps, also known as variable-speed heat pumps, don't turn on and off but instead run at variable speeds. As the inverter heat pump analyzes the conditions inside the home it adjusts its power output from 0% to 100% as needed
Manufacturers data should be checked and used alongside the site specific data to ensure that nuisance tripping is avoided but safety is assured

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Electrical

Circuit sizing and DNO approval

Installation of a suitable supply should always be carried out by a competent electrician.

Dedicated circuit required to be designed using manufacturers data (note CB size and type recommended isn’t always applicable)
Means of isolation adjacent to the external unit required for servicing and fault finding
communications/control cabling required between indoor and outdoor unit
Comms cable may require additional protection

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Installation of a suitable supply should always be carried out by a competent electrician.

Dedicated circuit required to be designed using manufacturers data (note CB size and type recommended isn’t always applicable)
Means of isolation adjacent to the external unit required for servicing and fault finding
communications/control cabling required between indoor and outdoor unit
Comms cable may require additional protection

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Electrical

Circuit sizing and DNO approval

Installation of a suitable supply should always be carried out by a competent electrician.

Notification to the local authority building control will be required as the heat pump is a notifiable activity under the Building Regulations
Easiest completed through a competent persons scheme (CPS)
This is separate to the notification to the DNO (see next slides)

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Electrical

Circuit sizing and DNO approval

Installation of a suitable supply should always be carried out by a competent electrician.

Electricity supply companies will need to be notified
Permission to connect may be required BEFORE the installation work starts
DNO could refuse to connect or withdraw connection (s)
See next slide for example form

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Electrical

DNO notification allows operators to record installation numbers of low-carbon technologies, which is critical for maintaining safe and efficient operation of the electricity network.

The process of the DNO reviewing your application can take between 8 to 12 weeks. If you are installing Distributed Generation equipment rated at 50kW or higher, you will need to complete a Standard Application Form (SAF)

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General guidance

Most heat pumps will have a relatively complex control system including weather compensators
Control systems will be set on commissioning
Customers must be advised on the use of controls
Commissioning should be undertaken by an appropriately trained person (depending on levels of complexity)

System Checks

Most checks are similar to any conventional heating system
Joints checked for leaks
Circuit pressure tested
All emitter circuits are open
Minimum system volume is adequate
Adequate anti-freeze and Biocide in relevant circuits
The last point is critical to the operation of the heat pump

The sensitivity of the weather compensation is set by picking a curve labelled by a number from 0.1 to 4. For example, when the outside temperature is 5 °C, the curve labelled 0.6 would result in a flow temperature of about 34 °C but. the curve labelled 0.5 would result in a flow temperature of about 32 °C.

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General guidance

Setting to work

Where by-pass valve is fitted ensure heating water flow rate is maintained when all circuits are closed
Check the design 𝚫t are achieved
Set heating and hot water controls to appropriate temperatures
Ensure zone valves and other associated controls are operating correctly

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Documentation and handover

Several documents should be completed and handed over to the customer after installation, whilst not exhaustive the documents may include the following;

MCS compliance certificate
Manufacturers commissioning report
All instruction, maintenance and servicing instructions
All diagrams

MCS compliance

Manufacturers commissioning

Instructions

Drawings

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Documentation and handover

Several documents should be completed and handed over to the customer after installation, whilst not exhaustive the documents may include the following;

MCS compliance certificate
Manufacturers commissioning report
All instruction, maintenance and servicing instructions
All diagrams

The MCS compliance certificate requires the following:

Is the system designed for intermittent or continuous use
Design external ambient air temperature
Total building heat loss at design conditions
What type of heat emitters are installed
Maximum temperature of the flow for the emitters
Verify the client has a copy of room by room calculations
Maximum temperature of the flow for DHW
Verify that the DHW reheat time is agreed with the consumer

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Maintenance

Maintenance on heat pump systems is a straightforward task for the heating engineer.

Very little more than any conventional gas or oil appliance

Signs of system water leakage
Heating system water pressure
Heating system water content and makeup
Expansion vessel size and pressure
Pressure relief valve (PRV) operation
System filters
System bypass
Buffer vessel if installed
Circulation pumps
Mechanical valves
Condition and grade of pipe insulation
Removal of anything that may obstruct the evaporator on an external system (e.g. leaves)

Maintenance on heat pump systems is a straightforward task for the heating engineer.

Very little more than any conventional gas or oil appliance

Control unit and alarm logs
Heating settings
Hot water settings
Indoor and outdoor sensors or thermostats

No tests can be done on the refrigeration circuit unless carried out by an F-gas registered engineer

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Maintenance

If you are the engineer on site, what key information would you require?

Key information required

Installation documentation
Diagrams
Commissioning documentation

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Maintenance

If you are the engineer on site, what key information would you require?

Key information required

Installation documentation
Diagrams
Commissioning documentation

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Maintenance

Checks expected to be inline with any manufacturers instructions

Number of checks carried out on heat emitter circuit

Can you outline how you would go about these, think as a plumbing and heating engineer?

It is a heating system after all.

If any faults found consumer to be consulted on remedials before any work is undertaken.

If any faults found on refrigeration circuit they must be repaired by an F-gas engineer only.

Manufacturers usually have access to F-gas suitably registered engineers to repair any parts of the refrigeration circuit.

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Fault finding

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NIBE

NIBE ASHP with SMO 20-40 control panel

Alarm 220 High pressure alarm-This is due to low flow rate of system water passing through the heat pump heat exchanger causing it to overheat this is linked to:

Low water pressure in the system (1 bar of water pressure is required)
Isolation lever valves is in a closed position
The zone valve, on the cylinder coil feed pipe, being in a closed position
Check for an air lock in the system pipework
Check for a failed charge pump
Check for a blocked Strainer (this should be cleaned annually as part of a yearly service)
Check the charge pump valves have not been left in a closed position.

NIBE ASHP with SMO 20-40 control panel

Alarm 301 Com error Slave 1-8-Slave 1-8 indicates the heat pump with the error code, if more than one heat pump has been installed.

This alarm is caused by the indoor SMO display module not receiving signal data from the heat pump unit:

Check the main fuse board for the house; checking the supply to the heat pump unit has not tripped out
Check the rotary power switch outside, by the heat pump, is not turned off
Perform these steps: Power down the heat pump unit outside for a minimum of 10 minutes then restart it. This will often clear the issue. You will also need to power off and on the indoor display module when restarting
A damaged cable between heat pump and SMO display unit could be the cause.

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NIBE

NIBE ASHP with SMO S 40 control panel

Alarm 229 High pressure alarm-This is due to low flow rate of system water passing through the heat pump heat exchanger causing it to overheat this is linked to:

Low water pressure in the system (1 bar of water pressure is required)
Isolation lever valves is in a closed position
The zone valve on the cylinder coil feed pipe is in a closed position
Check for an air lock in the system pipework
Check for a failed charge pump
Check for a blocked Strainer (this should be cleaned annually as part of a yearly service)
Check the charge pump valves have not been left in a closed position.

NIBE ASHP with SMO S 40 control panel

Alarm 271 Com error Slave 1-8-This is caused by the indoor SMO display module not receiving data from the heat pump unit.

Check the main fuse board for the house, ensuring the supply to the heat pump unit has not tripped out
Check the rotary power switch outside, by the heat pump, is not turned off
Perform these steps: Power down the heat pump unit outside for a minimum of 10 minutes then restart it. This will often clear the issue. You will also need to power off and on the indoor display module when restarting
A damaged cable between heat pump and SMO display unit could be the cause.

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PANASONIC

Panasonic heat pump units-

H62 flow switch abnormality – activated after 6mins

High pressure issue – check: cylinder zone valve is open; system water pressure (should be minimum of 1 bar); filter valve for dirt; and positioning of lever valves.

H20 Water pump abnormality

Possible grit in the charge pump or a failed pump unit.

H98 High pressure overload

Progressive build-up of pressure, causing the unit to overheat. Recommended steps would be:

To check the filter for clogging
Check the lever valves have not been knocked half closed.

Panasonic heat pump units-

F12 Pressure switch activated

This alarm would indicate a complete blockage of flow in the system. Recommended steps would be:

Check the zone valve going into the hot water cylinder is open
Check the filter for clogging
Check the lever valves have not been knocked half closed.

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HITACHI

Hitachi heat pump units-

If the system develops a fault, this will be shown on the main Hitachi controller. Normally it will display ‘TEXT **°C’. If a fault is detected it will display ‘FAUL *’.

The number tells the engineer what the fault relates to. Every so often the controller will self-check and you may see it display ‘FAUL 0’. This shows there are no faults and the system is operating properly.

‘FAUL 9’ means it has detected a problem with the heat pump. This is commonly air in the system, or a blocked filter, causing a high-pressure alarm in the air source heat pump. Other fault codes between 1 and 12 refer to sensors and the wireless thermostat controller.

If a fault code appears, the first action is to switch the mains power to the Hitachi controller off and on. This will re-set the unit.

Hitachi heat pump units-

High pressure issues-

This is due to low flow rate of system water passing through the system. Check the Y strainer filter unit, fitted to the return pipe work to the heat pump, is clear of dirt and debris – this is commonly installed with lever valves fitted each side of the strainer to allow it to be isolated off to allow for cleaning. This strainer should be checked annually at servicing.

Failed zone valves-

This type of system has multiple zone valves installed one for hot water production and one for heating production the way the system is designed to operate only one zone valve should be open at a time – Check that each zone valve is opening and closing when the system switches between operation functions.

Lack of system water pressure-

Check the expansion vessel pressure gauge – the gauge will have a black needle to show the current value. This system will require a minimum of 1 bar of system pressure.

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General heat pump faults

Incorrect Cycling

If your heat pump is on an off and on cycle, it could be overheating. This would be due to a malfunctioning blower or even a clogged air filter – cleaning or changing the air filter may solve this problem.

Another cause would like be the system’s thermostat which could simply need new batteries or be out of place. Other issues with the thermostat aren’t as easy to fix and are best left to a professional.

If the heat pump is running non-stop, the thermostat may be set too high. For example – in extremely cold temperatures, your heat pump must work a lot harder in order to keep your home warm. Setting the thermostat to a lower temperature to save it some effort may be the solution.

Making Unusual Noises

Rattling – if you hear this sound coming from your heat pump, it could be an out-of-place register or loose hardware. If the cover panels are not screwed on as tight as they should be, make sure to tighten them

Grinding or Squealing – make sure to turn off your heat pump immediately and call an engineer for a service visit. This could indicate a more serious issue, such as worn-out motor bearings

Blowing Cold Air

If you feel cold air coming from your air vents whilst your heat pump’s fan is running, there may be an issue with the heat pump’s thermostat. It’s best to not assume the worst, however. It is possible that a heat pump may go into a short defrost mode to prevent icing up. This means that there could be an output of cold air, but only temporarily.

However, if your heat pump is producing cooler air than usual, try setting the thermostat to emergency heat to see if warm air flows out the vents. If you do feel warm air, then the issue is with the outdoor unit. If not, you may have an air handler or defective thermostat to blame.

When inspecting the your outdoor unit, look for any frost or ice which may be forming on the outdoor coil of the unit itself. It may indicate a defective control module, defective defroster timer, or it could be low on refrigerant. Ensure you also check that the airflow to the unit isn’t restricted by grass or weeds.

A faulty compressor valve or refrigerant flow issue could also cause problem of the heat pump blowing out cold air.

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General heat pump faults

Sudden Loss of Heat

If your heat pump suddenly stops producing heat, don’t panic. The problem could be something that’s easily solvable such as adjusting the thermostat. Before anything else, this is something to be checked first, ensuring the heat pump is turned on and set to heat. You never know, someone in your household could have intended on temporarily switching the heat pump off, forgetting to switch it back on.

If you recently replaced your thermostat, this could also be the root of the problem. In this case, the thermostat may be the wrong type, or may have been wire incorrectly. Alternatively, if it isn’t the thermostat, the issue could be the lack of power caused by a tripped circuit – so you may need to check and reset the circuit breaker.

Not enough heat

If you find that your heat pump isn’t warming your home as much as you’d like, then it could be down to a dirty air filter or faulty parts. Reduced airflow decreases system performance and can damage the compressor. It is definitely recommended inspecting your air filter once a month, especially during the months where you tend to use the heat pump more. It is advised to check your heat pump’s care guide for model-specific instructions on how to replace or clean air filters if this is the case.

Other possible causes of a heat pump’s insufficient heat production may include potentially blocked air ducts, faulty valves or poor refrigerant flow.

Low pressure trip

Possible symptom-

Frozen air heat exchanger and no heat to the property

Possible cause-

Fan stopped or slowed

Too little air-flow across collector

ASHP undersized

High pressure trip

Possible symptom-

Loss of heat through emitter circuit

Possible cause-

Poor flow rate through emitters (and condenser)

Air in the heating system

Blocked filter

Conflicting controls

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