Vaillant Arotherm Owners Thread

[Timbones (Tim)]

This is the beginning of the hot water cycle, when the valve switches from CH circuit to DHW circuit. The water in the cylinder’s coil (or plate heat exchange) is much colder than the water in the heating circuit, so the temperature plummets. Quite normal from what I’ve seen. Some more examples / explanations in this thread:

Improve efficiency: After heating the domestic hot water pump the radiators for a bit

This tweak is going to look a bit odd. It’s benefit is more pronounced if you are turning the heat pump on and off quite often. Following a burst of heating the hot water in the cylinder the flow temperature will be high. For example, my hot water is set to 42C which gives a flow of 58C when my heat pump has finished. The trick is then to shut off the heating energy but pump the toastie water around the radiators. This doesn’t sound like it’ll do a lot, but it’s one of those “every little hel…