Gas revision 3

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Gas revision 3

Which fitting should not be installed on a suspended floor where the fitting would be hidden by floorboards?

1 point

a) Push-fit

b) Solder ring

c) Capillary

d) Type a compression

Clear selection

A room sealed boiler with the fan downstream of the heat exchanger and a natural draught open flued appliance with a draught diverter, would be classified by which of the following?

1 point

a) C13 and B1

b) C12 and B 1

c) C1 and B 13

d) C12 and B2

Clear selection

When testing for spillage on an open flued appliance you realise that there is an extraction fan in the connecting room, how would you proceed with the spillage test?

1 point

a) Close all doors and test after the appliance has heated up for 5 minutes.

b) Turn off the fan and open the door then test.

c) The fan is probably intermittent and therefore would not affect the performance of any flue because of its location.

d) Open the connecting door and turn the fan on then test.

Clear selection

If you discovered an LPG gas hob connected to a natural gas installation, what would you do?

1 point

a) Disconnect and issue an ID notice.

b) RIDDOR report the installation.

c) Warn the client of the potential dangers and issue a NCS notice.

d) Consider the installation at risk.

Clear selection

An electrical thermostat on a boiler:

1 point

a) controls the supply of gas often via the operation of a solenoid valve via mechanical or electronic switching processes.

b) controls the gas rate of an appliance via a calibrated optimising device.

c) controls the room temperature via a series of electronic or mechanical switching processes.

d) controls the efficient operation of a boiler independently and without the need of an interlock.

Clear selection

An air vent in a wall has 50 openings of 10 x 20mm, how much free air can pass through this vent?

1 point

a) 10cm2

b) 100cm2

c) 1000cm2

d) 10000cm2

Clear selection

When fitting a label with information about ventilation to an appliance, which of the flowing pieces of information should be recorded on that label?

1 point

a) Address of property and type of appliance

b) Installer name and responsible person

c) Gas Safe registration number and installer name

d) Gas Safe registration number and address of property

Clear selection

A slow ignition device installed in a multipoint does which of the following?

1 point

a) Prevents explosive ignition.

b) Creates economical heating of water.

c) Assists the economical combustion process.

d) Prevents scale build-up.

Clear selection

If a flame from a burner is over-gassed and impinged the surfaces within a boiler combustion chamber, what visual effects could be expected when examining the appliance?

1 point

a) Soot and blockages of heat exchanger flueways

b) A very clean area

c) White dust on the heat exchanger

d) Melted components

Clear selection

A differential of pressure across the diaphragm on an instantaneous hot water heater is created by which device?

1 point

a) Water throttle

b) Expansion joints

c) Venturi

d) Slow ignition device

Clear selection

While carrying out an inspection of gas appliances in a dwelling, you discover an open flued space heater is fitted in a bedroom – what essential device must be fitted to that appliance?

1 point

a) An isolation valve

b) An atmospheric sensing device

c) A mercury vapour device

d) An interlocked solenoid

Clear selection

To confirm the suitability of an existing chimney class I, BS 5400 Part 1, requires the engineer to carry out which series of checks?

1 point

a) Internal examination of the flue liner, soundness test, the length of the installation, check termination and seal off closure plates

b) Note any changes of direction of the flue, openings, termination position and check for spillage

c) The flue route, are there any other connections, the location of termination, is the flue sound (ie flue flow test) and check for physical condition of the outside of the flue

d) Visual inspection of the flue on initial survey, talk with responsible person about the type of fuel used on the flue, carry out a spillage test and recommend the chimney swept by a Gas Safe chimney sweep

Clear selection

If gas pipework is installed and it travels through a cavity wall, it must comply with the which of the following?

1 point

a) It has to take the shortest route and be sleeved, ie steel pipe, and sealed with a flexible and fire resistant seal.

b) It has to take any route as long as it does not exceed 450mm and is appropriately sealed.

c) It has to take any route as long as there are no joints in the seal and it is sleeved.

d) It must have isolation points at either end of the sleeved and sealed route through the cavity.

Clear selection

When an appliance fails a spillage test you can retest by heating up the flue for a period of time then testing again. If the appliance fails the spillage test you can open a window in the same room and test again until a successful outcome is achieved. How would you then proceed?

1 point

a) Fix the window open and install a fine mesh in the gap.

b) Install a fan capable of providing the required amount of air and fix a safety interlock to the gas valve of the appliance just in case the fan fails.

c) Measure the gap created by opening a window and install a permanent vent equivalent to that size.

d) Simply ask the customer to open the window to the calculated amount when operating the appliance and issue an AR (at risk) notice proving that you have asked them to do so.

Clear selection

What is the minimum cross-sectional area of a flue block use for a gas appliance in a new building?

1 point

a) 16500mm²

b) 15500mm²

c) 14500mm2

d) 12500mm²

Clear selection

Whenever a vertical flue pipe intersects a roof, what is the minimum up-stand required to create effective weather-proofing?

1 point

a) 150mm

b) 175mm

c) 200mm

d) 250mm

Clear selection

‘The effectiveness of the performance of a flue can be affected by aerials, wind turbines, trees and large obstructions in close proximity.’ True or false?

1 point

true

false

If an open flue boiler of 28kW gross was installed in the situation below, what size should the vents be?

1 point

a) 92.28mm² for both the external and internal vents

b) 92.28mm² for the internal event and 105mm² for the external vent

c) 105mm² for the external event 210mm² for the internal bank

d) 28mm² for the external vent and 56mm² for the internal vent

Clear selection

If we use the example in question 19 and the installation was modified because there was an extra room installed between the boiler and the other internal wall, how would it affect the size of the internal vent?

1 point

a) It would increase the previously calculated dimensions by 50%.

b) It would increase the previously calculated dimensions by 75%.

c) It would increase all of the vents both internally and externally by 100%.

d) There would not be change in dimensions is required.

Clear selection

When a complete combustion occurs, what would you expect the constituents of the flue products to be?

1 point

a) Methane, carbon monoxide and aldehyde

b) Carbon dioxide, carbon monoxide and soot

c) Carbon dioxide, nitrogen and water vapour

d) Methane, ethane and propane

Clear selection

The minimum angle of the offset for a flue block is which of the following?

1 point

a) 30°

b) 45°

c) 50°

d) 75°

Clear selection

What type of gas appliance would be classified as B11?

1 point

a) Closed flued appliance without a draught diverter

b) An open flued natural draught appliance with the draught a diverter

c) A vertex flued appliance

d) An open field appliance which incorporates a fan

Clear selection

The approximate flammability limits for natural gas are:

1 point

a) 5 to 15% gas in air.

b) 2 to 90% gas in air.

c) 100% gas in air.

d) 80–90% gas in air.

Clear selection

Name a gas control assembly that is commonly fitted to a space heater, as shown in the image below.

1 point

a) Solenoid valve

b) Atmospheric sensing device

c) Multifunctional gas valve

d) All of the above

Clear selection

If a tip of a thermocouple becomes damaged or its connection with the thermoelectric device is loose, what may be the outcome?

1 point

a) The pilot light will not stay lit.

b) The appliance will override the fault.

c) The overheat device will operate.

d) Gas will escape from the pilot assembly.

Clear selection

If a bypass port on an oven thermostatic control becomes blocked with grease, which of the following outcome will occur?

1 point

a) The oven will overheat and burn the food.

b) The oven will not light.

c) Once the oven reaches temperature, it will turn off and not continue on maintenance rate

d) The oven will operate on low heat only.

Clear selection

If a regulator, shown below, with a seal intact installed on a U6 meter installation emitted the smell of gas, what could the problem be?

1 point

a) Back pressure from the meter was is the diaphragm and causing the smell to travel via the pressure relief valve.

b) This is a normal occurrence during operation of the meter when working at full capacity.

c) There is a split in the diaphragm of the regulator.

d) Outcome of the safety process to prevent the meter from being over-pressurised.

Clear selection

Condensing boilers incorporate several devices to control there safe and efficient operation including flame rectification systems to act as flame supervision devices. During there operation they also have a gas control called ‘zero governor’ which supplies different volumes of gas to the burner in direct relationship to the speed of the fan which provides air for combustion. Select another term that is used to describe such a control device from the list below.

1 point

a) Air–gas ratio valve

b) Multifunctional gas valves

c) Fan valves

d) Relay valves

Clear selection

The pilot flame, which envelops the tip of this component, will begin the process to help create a small current which will energise a magnet at the thermoelectric device where the end of the components is connected. What is the name of this component shown below?

0 points

a) Test probe

b) Thermocouple

c) Flame sensing device

d) Bimetallic strip

Clear selection

If a flue damper is discovered in the chimney and a new gas space heater was to be installed, what essential action should be carried out?

1 point

a) Remove the damper completely or fix it permanently in the fully open position.

b) Adjust the damper to allow the products of combustion to disperse efficiently.

c) Adjust the damper temporarily and use it for testing purposes at a later date.

d) As long as there has been a successful flue flow test carried out leave it in the open position, inform the customer and mark it at risk.

Clear selection

If a metric domestic gas meter passes 0.07m³ of gas in a two-minute period with a gas appliance connected, what would be its net rated heat input?

1 point

a) 70kW

b) 7kW

c) 22.6kW

d) 24.9kW

Clear selection

The typical gross calorific value of natural gas, approx. 38.5 MJ/m3 can be found printed in which document user document?

1 point

a) Any gas appliance documentation

b) LPG bottle sales receipt

c) Council Tax invoice

d) Domestic gas bill

Clear selection

Option 1

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Option 1

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