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Anyone taken a thermal image of their ASHP condenser unit?

heat-pump-newbie · 2022-09-08T09:47:03Z

I suspect a drop in the COP of my heat pump may to be due to a previous loss of refrigerant. I can't prove this but I've seen bands of frost forming on my condenser unit during cold damp weather. Without doing a time lapse video of the frost forming I can't prove that the bands are always there, or are only formed during the freezing or melting of the frost. This only becomes visible of course in cold damp winter weather, but it's just dawned on me that if I could monitor the operation right now using a thermal camera I may well see those bands all the time. Has anyone done this eg with a Flir ? @admin didn't you have one of those ?

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Air Source Heat Pumps (ASHPs)

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heat-pump-newbie

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Topic starter 09/09/2022 7:10 am

No, it's R32. A split system so it's pumped from the outdoor unit up the outside wall to the indoor unit in the loft.

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SAEnergy

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09/09/2022 5:10 pm

if you have witnessed a refrigerant leak then the system will need to be thoroughly checked. The joints are flared and should seat perfectly. If they don’t and it leaks you have a dead system.

These units a preloaded for a run of up to 15m (generally). So in a short run you might be ok in terms of refrigerant load.

however, and this is the important bit. If refrigerant got out, then it is highly likely that moisture and or air got in. These are non compressible and will cause a fault.

the best course of action is to have a proper fridge engineer come out and follow the service procedure to recover the refrigerant, fully nitrogen load and vac test the system. Then add the correct amount of refrigerant for the system. The preload amount should suffice unless it’s a long run.

the risk of not doing this are not just reduced COP but total compressor failure.

That banding is not a good thing.

Internationally recognised award winning installer of heat pumps and stuff

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heat-pump-newbie

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Topic starter 09/09/2022 6:53 pm

Ooh @seaenergy that's a bit worrying !!! I'll have another go at my installer then. Thanks very much for you advise. It's been running like that for over a year now - is it in trouble ?

I've sent an email to my installer to remind them that I asked about this at the service last April.

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SAEnergy

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09/09/2022 7:31 pm

@heat-pump-newbie I would want it properly checked out. If there is a refrigerant leak it’s rarely a good thing. You could be very lucky and it’s all good.

The banding can happen for a number of reasons, the bottom coils for example sometimes use a base heater to heat them as that’s the part of the coils that gets the least heat recovery in defrost cycle.

I expect having it properly checked is cheaper than a new unit A lot of installers are not AC guys, when I do split units I bring in a specialist company to do the refrigerant pipework. They may need to get someone in to do the job properly.

Internationally recognised award winning installer of heat pumps and stuff

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