AirSource Heat Pump Freezing temperatures

mmwweight

Hi, 

We have a Stiebel WPL 17 Classic Heat pump installed, when the temperature gets to freezing, we find we have a drop in pressure and the heat pump stops working. The pressure has been consistent for weeks prior to that and everything working fine. This has happened three times now. Do you think this is a leak? If so why does the pressure only drop when it is freezing or could it be something else? 
We have underfloor heating upstairs and downstairs. 

Thanks

Netexporter

Could the condensate drain be freezing?

MultiFuelBurner

mmwweight said:

Hi, 

We have a Stiebel WPL 17 Classic Heat pump installed, when the temperature gets to freezing, we find we have a drop in pressure and the heat pump stops working. The pressure has been consistent for weeks prior to that and everything working fine. This has happened three times now. Do you think this is a leak? If so why does the pressure only drop when it is freezing or could it be something else? 
We have underfloor heating upstairs and downstairs. 

Thanks

When was it installed, when was the last service and anti freeze level checked, do you know if your system has a backup electric heater that activates when conditions are freezing? Additionally do you have freeze setting so that when the outside.temp.is.5oC or lower the ASHP maintains a flow of day 20oC. This will undoubtedly be in an installer menu so time to get the manuals out and check it all.

Do you run your ASHP 24/7 or stop it all together overnight when the outside air is coldest then start it int he morning?

We recently had a smart water meter fitted I don't suppose you have one to monitor for leaks as it's easy from the phone. The alternative is to take a period where you know zero water use has occurred to no showers, washing up, toilet flushes etc but when the heating is running and take a manual reading at he start and and of the no other use of water and record the results.

Reed_Richards

This is a wild guess but some heat pump systems don't use antifreeze, they have a valve that opens when the internal water gets too cold and it lets all the water out to stop it freezing.  Normally that should only happen after your heat pump has not been used for a prolonged period.  If you have such a valve and it was a bit faulty so it gets triggered prematurely when its cold out to be slightly open that might just give you the symptom you describe.