Greetings from cold Finland! Has anyone figured out the defrost logic for Altherma 3 R? I have the hydrobox model, but I don’t think the indoor model matters as long as the outdoor type is the same ERGA04-08EVA. It’s my first winter with Altherma and the only thing that bothers me is that when outside temperature drops below ~-6C -7C or something like that, the system starts to defrost itself like crazy without any reason. The outdoor unit is’t frosted at all and it still defrosts itself every 30-42min. Outside humidity is 70-80% so it definitely should do that.
Last night was a good example when the temperature started to rise the behaviour totally changed. 18:00-21:00 it was a defrost loop with frequent defrosts and when the temperature started to rise it got normal, with defrost cycles ~many hours as you can hopefully see.
So has anyone figured out the defrost logic with this device? I have ESPAltherma installed so I can see a lot of sensors but I haven’t figured out what the logic is. Outdoor temperature, heat exchanger mid temperature…?
I’d love to know if someone has the same observations! And I do know that defrost cycle can be around ~1h when humidity is high etc and then it’s totally ok to defrost - when the outdoor unit is covered in frost! The problem is that defrost happens when you can clearly see that it’s not needed.
I’ve tried changing dT and a lot of other stuff but the only thing that seems to matter is the outdoor temperature - and that I can’t change