ᐅ Timer for domestic hot water heat pump

Hello, I have a quick question and would appreciate any advice. We installed a ventilation heating system with a domestic hot water heat pump. Now, the hot water heating switches on in the evening after washing and in the morning after showering—basically when there is no sunlight. We also run a photovoltaic system connected to the meter. Would it make sense to operate the domestic hot water heat pump with a timer switch for just 2 hours at midday when the sun is shining, or would frequently turning the heat pump (essentially the water heater) on and off with a timer cause damage? Background: the heat pump turns on automatically as soon as the water temperature drops below a certain level and then heats the water up to the target temperature. The ventilation heat pump operates independently from the domestic hot water heat pump. Many thanks in advance for your insights.

If you need hot water outside the scheduled operating times, do you go down to the basement and turn the pump on manually?

I wouldn’t do that – simply for convenience. Of course, you can save electricity this way, but is the loss of comfort worth it?

My heat pump reports an error if the software tries to start the water heating but the pump doesn’t turn on (because there’s no power).

Hot water always has priority for me (as specified by Stiebel), so it will always try to produce hot water when the target temperature is not reached, which means it won’t heat otherwise.

Maybe you can work with day/night programs? Set the target temperature for hot water to 4°C (39°F) at night and 45°C (113°F) during the day – though it’s inconvenient if you want a shower in the morning and there’s no hot water….

A timer switch is less suitable for this purpose. A small PLC (e.g., Logo) for intelligent control achieves the desired result without loss of comfort. The prerequisite is having knowledge of the subject or consulting someone who does...