TonyP

Reed, Thanks - very useful, and pretty much as I expected. It's just so hard to locate all these in the installer settings, and then the exact meaning of each parameter is pretty obscure. However, when I change the User Settings from Heat to Auto the heat pump ceases to heat the house. I have a Honeywell Evohome controller, setting the on/off times and temperatures in 3 zones. Can I use Auto mode with this, or must I use the LG controller, which currently resides in the hot water cupboard, so is always very warm and would therefore will almost never ask for heat. Or, could the cause be the outside temperature thermometer was not installed or properly connected? In response to your comment about radiators: when we moved from the gas boiler to the heat pump we replaced all the double panel rads with triples, and all single panel with doubles, ensuring an oversize factor for heat output of between 3 to 4 (compared to the standard heat output value given by the rad manufacturer) in each room, so I'm hopeful the rads aren't the problem.

Therma V - minimising the water flow temperature My energy usage is very high (measured in kWh, rather than £s as obviously energy prices are crazy) as compared with my previous gas boiler heating system. Is it possible to reduce the flow temperature, since a lower flow temperature should improve the COP? I've spent many hours searching for information on this, but without success. My best guess is to select 'Auto/AI'. (The system had been set to 'Heat'). Then Auto will presumably lower the flow temperature whilst maintaining the desired room temperature. If so, what exactly do the AI values (which range from -5 to +5) do? What should be a starting value? (It seems to default to zero). If the room temperature is lower than the desired value, do I increase or decrease this AI value?