signorjim

Hi there - I wonder if anyone can help. New Altherma system takes hours to get up to temp after a DHW cycle or defrost. The refrigerant quickly heats up to 31 degreees c and then ticks up by a degree or so every fifteen minutes meaning that the leaving water temperature doesnt get up to temperature for a long time. Its pushing 17 litres per min, fixed, radiators as heat emitter. Cant figure it out. It feels like there is a setting somewhere making it go v slowly... We have normal radiators in the house (apart from UFH in the kitchen which has the water temp lowered by a valve)but the Altherma has three possible settings - UFH, Fancoil (restricted to max 55c but you can alter the delta T between 1-10c) and radiators (max 70degree lwt but you cant change the delta T - its stuck at 10). The DHW is set on schedule for an hour mid-afternoon and an hour at midnight and mostly works fine but occasionally have to top it up. Is it possible12kw is not powerful enough? I imagined that a defrost cycle knocks the temp back for 8-10 mins or so when the unit defrosts but then should get to temp again (we also have the additional small reservoir to minimise water temp drop during defrost). If it cant get up to temp in between defrost cycles then the whole thing is a bit useless for three months a year...