Heat Pump Mount

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• Hang cross bar
• Hang arms.
• Arms are adjustable in width - ________ inches to each side
• Lineset 6’ is ok
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Adding Refrigerant

Measure both lines. Add to blue line only. The lower p side, using the Blue knob.

Hi P Line

Connected to liquid line

Lo P Line connected to vapor line.

Hi P Gauge

Lo P Gauge

Connect T gauge to liquid line

Read subcooling on liquid line

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• Connect hoses, make sure valves are closed on vacuum pump
• Purge hoses - after connecting, we have air in hoses, use 3rd hose, crack it open, then turn the blue and red knobs open.
• Roughly 2-4 lb refrigerant are used per ton of AC
• Purge air from the R410A tank line
• Connect both hoses
• Service hose (yellow goes to supply tank)
• Charge into the suction line (vapor line)
• For safety, want to charge on the low pressure side (less resistance to supply gas flow)
• Add slowly, just cracking blue knob slightly and watching slight rises in low side pressure gauge. Look at scale - add 0.2 oz at a time.
• When close to finished, discharged what was remaining in the hose from bottle to low pressure side.
• Disconnected the high pressure from heat pump, and suck its fluid out into low side
• In this example, added 37 oz of refrigerant - quite a lot.
• End point was 10 deg subcooling. Adding refrigerant reduces the subcooling. Started above 32
• Then used test caps for leaks

https://hvac-blog.acca.org/its-easy-to-make-money-recycling-refrigerants/

When starting to run heat pump to begin filling, make sure R410a on low side is above 32F, or you will get icing. This is from too little refrigerant.

How to Determine the Correct Charge

Undercharged if too little subcooling - add refrigerant to low side.

Overcharged- remove refrigerant

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• Look at your pressure for cooling mode, on the low P gauge.
• Pressure corresponds to boiling point, and 102 PSI means about freezing. Thus, must have higher pressure than 102 PSI for your outdoor coil to freeze. That is a start. But how much? There is a 43 psi range, but the correct value is not just in the middle, need to determine that from Subcooling Method.
• Need to measure subcooling - how much you are cooling below boiling point
• Measure subcooling on the liquid line (thin line connected to red gauge)
• The Thermostatic Expansion Valve automatically will take care of the vapor side - read on the blue gauge
• The measurement has to be taken on the red valve
• In this example - we have 100F
• We measure the liquid line with an external probe, get 90F
• That means we have 10F subcooling - the specs for your pump state a typical 10F subcooling (+/- 3) so you are charged right.
• If you have less subcooling (say you are reading 96F on the probe

Understanding Subcooling: Is Cooling Working?

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• Understanding how it works allows you to:
• Know when it’s working properly: check subcooling. In winter, too.
• The thin line at the heat pump is the liquid line. It is always the liquid line, but could be high or low pressure. Liquid=cold in cooling, liquid = warm in heating. Condenser= outside, evaporator=inside; TXV (expansion device) is before the evaporator and before compressor - 2 in a heat pump.
• Intuitive understanding:
• Subcooling method: connect high side to the liquid line
• High side is the line of the compressor outlet. Outlet is always high pressure, but it can be switched via the Reversing Valve to the indoor or outdoor coil. Therefore, the outdoor unit can be a condenser or evaporator, and the indoor unit can be a condenser or evaporator.
• Note that home heating usually requires much more energy for a home than cooling (in temperate zones). Logic is simple: 0F to 70F is a 70F difference, while 100F to 70F is only 30F difference. But if you have 120F to 70F and 20F to 70F comparison cases (usually in different locations), then figures should be similar.
• For an electronic system (EEV) - can’t use subcooling or superheat levels to check refrigerant charge state
• BUT - doable between 37 and 70F - so in winter need to put a scumbag on it - a heat pump charging jacket. Cardboard or tarp could do it.
• Cooling mode, TXV system
• High valve is connected to the liquid line
• In this example, too much subcooling means we are overcharged. Need to remove refrigerant to reduce subcooling.
• Only check possible, outside of blocked airflow - is heating mode works fine - no funky noises
• Hot line (vapor in heating mode) should be 100-110F hotter than ambient, no P gauges involved

Concepts: How a Heat Pump Works

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• Understanding how it works allows you to:
• Know when it’s working properly: check subcooling
• Where is the compressed fluid heat-exchanged - inside or outside
• Blow heat inside house or outside house: means you are compressing indoors (heating indoors) or outdoors, or conversely, expanding indoors (cooling indoors) or outdoors
• How to understand subcooling: indoor expansion means you cool by X degrees. If you are air conditioning, then the incoming gas must be around 20C and cooling down to 5C = 41F.
• Subcooling is simply the degrees below boiling point. In the diagram for cooling mode, it is how much heat was lost in the condenser (outdoor unit), so it’s measured at the liquid line.
• Or: Compressed (and cold) line liquid cools upon expansion to vapor. Measure subcooling (how much T liquid lost after expansion) - should be difference in temp between the hot and cold line
• The thin line at the heat pump (in cooling mode) is the liquid cold high pressure line. It is always the liquid line, but could be high or low pressure. Liquid=cold in cooling, vapor = hot in heating. Condenser= outside, evaporator=inside; TXV is before the evaporator and before compressor - 2 in a heat pump.
• The thick line is the vapor line, but it could be either high pressure or low pressure depending on the mode
• High pressure vapor is higher pressure than the liquid line (heating)
• Low pressure vapor is lower pressure than the liquid line (cooling)
• Thus - there is always a vapor line and liquid line. But, in heating mode, the vapor line is higher pressure than the liquid line - so we cannot just say the ‘higher pressure line’ is always the liquid line. Both lines have to withstand the pressure. The larger diameter allows for vapor to move with less restriction.

Indoor unit in cooling mode

(compressor output goes to outdoor unit)

Indoor unit in heating mode

(compressor output goes to indoor unit)

Lines at the heat pump

Don’t overcharge, or you can have liquid going back into the compressor, which will break the compressor. Undercharged - means you can freeze the outdoor heat exchanger.

Thin line

High P and higher P

Than vapor line

Thin line

High P and lower P

Than vapor line

Concepts: Adding or Removing Coolant

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• Precharged heat pumps have refrigerant fluid inside the outdoor device, which is released later. To understand how to add or remove, first understand the pressure of the refrigerant inside the machine. Is it higher or lower than atmospheric? If higher, then opening valves would mean it escapes into the atmosphere without letting air in. If lower, then it will escape into the atmosphere and let air in.
• The answer is: typical pressure is 200-400 PSI, which makes sense, otherwise there is hardly any fluid in the system
• How do you measure this pressure? With TXV-based heatpumps, you measure at the high pressure line (red gauge).
• So for example here, we read the high T gauge - we show about 320 PSI, and the gauge and refrigerant is 100C - the 100C is the saturation temperature.
• If you had too little fluid, your saturated temp would be below the freezing temperature of water, and the exchanger coil would ice up. Here, at 100 PSI, we read that the saturated temperature of 100 PSI gas is about 30, so atmospheric moisture will freeze on your coil, preventing heat exchange.
• If you got too much fluid, you’ll have liquid returning to compressor, which can kill your compressor.
• You can tell you have too little refrigerant if your heat exchanger is icing up.
• Examine the rating plate to tell you how much subcooling you need (difference between measured temperature and pressure gauge saturation temperature).
• Ex: Saturated temp reads 100F
• You mesure temp at thin line (high pressure) and you read 90F. That is the correct level of subcooling.
• Saturation temperature is temperature at which liquid boils to gas. This depends on the pressure.
• To do this procedure, let heat pump run for 10 minutes. You are checking this while running the machine.

gauges here are F + PSI

Ther is a range but in practice this will do. If 40F, then have 6F subcooling? This is for AC, not heating.

About

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• Senville Aura has a thermostatic expansion valve
• THe small fluid line is high pressure (liquid) line and the large line is the vapor line

SEH 1 Field Notes: SEH 1 Install

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• Opening up the low pressure valve resulted in refrigerant escaping through the valve around allen key
• Felt very cold, see pictures.
• Could not shut it? I recall so. Or I would have shut it off immediately.
• This continued for about 5 minutes
• I assume leftie loosie - turning left opens the valve
• This is wrong procedure - as low side is opened only after pumpout.
• This may still work?
• Note - some of the liquid that came out was oil. Greasy residue on threads

Hi Side

Low Side

Pressurized

Atmospheric Pressure

This is a diagram of the physical reality

Post-mortem: opening the valve prior to pumping is indeed retarded. Since this is high pressure inside, it would leak out: open op a pressurized container in any way - and shit will leak out:

What happened? I opened the low pressure side (assuming presence of check valve which would make nothing happen). Let’s say when gas is just sitting there, it is not being compressed, so pressure should be lower than during operation. This vid shows pressures around 120 and 350 PS for compression vs low p side. So the charge must be quite high inside - and it could definitely blow out the low pressure side if opened to atmospheric pressure. Note This vid shows case of constant orefice (not TXV)

Derivation

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Hi Side

Low Side

Pressurized

Atmospheric Pressure

What happened 2? If the indoor unit was already evacuated, and filled - we would have sycked, then opened the high pressure side. If the low pressure side was opened, air may have gotten into the system, or refrigerant came out and started filling indoor unit. Don’t know.

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Can look at final running pressure to determine if we need more refrigerant. The vacuum pump gauge can tell us.

Installation - Indoor Unit

Manual PDF. Short PDF for Installation.

1. Install indoor unit 91” or higher from floor
2. Mounting bracket must be attached to studs or otherwise sufficient structure
3. Wall through-hole must slope down slighly to the outside to facilitate drainage
4. Go out to left, right, or side as needed.
5. Outdoor safety disconnect is required for unit

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Note that if you do this, you also need to shift drain hose to other side. Don’t do this - requires an extra bend in tubing instead of going straight out the back.

Fluid Lines

Manual PDF

1. Outdoor safety disconnect is required for unit
2. 240V 20A double breaker
3. Indoor unit electrical connects to outdoor unit as 1-2-3-ground

Electrical - Senville 24HF-Q

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• Bend lines out of indoor unit 90 degrees
• Poke through wall, use protective thimble, tape up fires so you can feed through wall.
• The black and green cap - may be nitrogen inside (for pressure testing)
1. Lubricate flare, and tighten down with wrenches
• Line hookup + pump
• Evacuate system at the single evac port
1. (low P side is the larger tube)
2. In vid- pump is different than our

Vacuum pump

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Wiring Outside on Heat Pump

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• 240 + connection to indoor unit + ground - connect the 5 bottom wires + ground the source + indoor unit
• Use Nylog sealer - connect indoor unit. Then connect pump. Thread on Leak Lock and Nylog. Nylog has mixed reviews.
• Pump it for 15 minutes to -30 mm hg.

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Note that utility power is 10/2 at 240V (3 wire), not 10/3. Note also that indoor unit is 4 wire. It appears 1 wire for signal, and 2 others for power at 240V.

Wiring - Indoor Unit

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• 1-2-3 wires by color + ground
• 1=grey
• 2=black
• 3=red
• What is

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Pumpout detail

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• Remove service caps (3 total - includes service port). Vid

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This is what you pump. Low pressure side. Evacuate this. Gas is inside the unit, precharged - and you release with hex key.

Precharged high pressure side. Refrigerant is inside unit. Let gas out from the high pressure by turning key. P. 30.

• Connect service port - it has a shrader valve. Tighten by hand only.

Vacuum Pump

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• Manual

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Lessons: in cold weather, vac pump does not work, air entraps in pump oil and top smokes (video on YT)

• But, this is actually ok. Oil gets cloudy and some smoke comes out, but Google sez that is ok

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1. Tubes kink easily. If you leave a tight space between exterior and interior unit, tube routing is difficult. See kinks in pictures.

Pumpout detail

video

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• Pump out the low pressure line to minimum (15 min)
• Observe that it doesn’t leak (15 min) - still at minimum
• Crack high pressure refrigerant release - but only so it goes slightly above atmospheric pressure - about 1 psi
• This is to lose minimum amount of refrigerant, not so much as checking for leaks. Understand this point.
• No loops where liquids can be trapped.
• To fill up with more refrigerant - see this video?
• Note - Senville Aura appears to have internal oil traps? No, it dosn’t need them due to short pipe length.
• Refrigerant refill - r410a

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Vacuum Pumpout Detail

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• From this video
• After pumpout - this order:
• Shut the blue valve
• Turn pump off
• Gauge set - the quick-coupler-looking connections are not actual connections
• You just attach blue/red coupler there for storage

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Questions

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• Huh? The low side valve was opened only _after_ pumping in this video. Isn’t that completely wrong - and the guy evacuated the refrigerant into an un-evacuated state?
• Opening valve after pumping means that the guy was pumping only up to the valve? Ie, pumped out the blue hose only - the pressure is still inside the copper tubing
• Since instructions and videos are consistent in opening high and low pressure valves only after pump-out, the conclusion we must draw is that the valve does this:

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Quality Control

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• Drain hose - from inner unit - Remove the air filter and pour a small amount of water into the drain pan to make sure that water flows from the unit smoothly.
• Electrical to Indoor Unit - Using wire crimper, crimp u-type lugs on the ends of the wires
• To feed power cable to indoor unit - ‘Facing the back of the unit, remove the plastic panel on the bottom left-hand side.’
• Bundle all tubing/wiring (4 of them) to pass through wall hole -
• Drain hose is at bottom (avoids water traps)
• You can wedge up the indoor unit to make connections behind unit
• Don’t forget drain joint on outdoor unit
• Make sure wall mount can handle 4x the weight

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Quality Control 2

• Use right cable outdoors -
• Respect bend radius of 4”
• Follow torque requirements
• Fill line with refrigerant to slightly above atmospheric
• Test run, highest and lowest temp
• If too cold, go with manual control

Is cable 10/3 or 10/2?

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About Heat Pumps

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• Compressor- condenser - thermal expansion valve -evaporator
• How a heat pump works
• Thermal expansion valve meters the amount of juice that should go into evaporator. It consists of a bulb that senses temperature, with a working gas that expands to move the control needle.
• Superheat is temperature above boiling point
• Good video of how heating and cooling mode works with Reversing Valve. Note expanders have parallel check valves.

Troubleshooting

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• If excess vibration noise -
• 1. there are special grommets that you can be installed under the compressor. This works but it is a pain to install.
• . make sure the lineset is not touching the walls (use arma-flex around the lineset in the whole)
• I find adding vibration pads under the units helps alot. Don't use cheap pads.
• If the compressor is also noisy use a soundjacket.

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