Save now as it will probably cost you when it starts needing parts
Enjoy
Actually Dream have been very helpful when I contacted them after 18 months use I had a Capacitor fail they dispatched several parts the same day (free of charge) better service than you get from most bigger companies. Especially the low purchase price of ÂŁ1500 for 15 Kw to heat my whole house. I am still impressed with it`s performance and value for money, compared to all the other horrendous quotes I had in 2012.
Stokegoldng UFH would better suit HP. Rads may need oversizing. As you are well insulated, the 22 Kw may not be needed, mine is a bit oversized at 15 Kw. A plumber with calcs & knowledge should be able to install for a fixed price whether he may have the experience to get yours right first time, remains to be seen. Indoors ducting not advised, outdoors much preferred for essential air flow. Chinese instructions need re translating I agree ! but I was very impressed with a reply from China when inquired about wiring in an external digital control, they supplied details in colour within minuets.
Bobs dream "Iced over" This can/will happen with high humidity / dew point temp being met, also at these temps the COP will not be favourable, I inhibit my use with a digital optomiser, to avoid lower COP`s (light your log burner) mine swaps to gas.
PP06 error code, that's possibly frost protection not set correctly, another of my reasons for not running at those temps.
what settings are you at ? I keep heating output below 47 degs.
"2 pumps inline" are they in parallel ? Have you fitted a strainer & magna clean in line ? Good flow, Blocked, flushed ?
Regards Buffer tank, Cylinder, calcs. stats. needed.. Worcester need your expertise sir !