Program heating settings for nighttime

Non-working heating can justify significant rent reductions. I would not take that lightly.

Repair the external sensor, shorten the night setback. That should be enough.

ice cold

Sure; not ice cold; but what does ice cold actually mean in this case? @OP?

It should be 18 by now.

Why drive away a tenant if they are not behind on their payments? I would fix the problem before a rat moves in who doesn't pay. If you are satisfied with your tenant, then don't be too stingy to fix the condition. What if it happened to you like that, would it be okay for you if you were freezing and your landlord said: I don't care?

Thank you for all the answers.

I will reply as best as I can with my current level of knowledge.

So: As far as I understood the technician, you cannot adjust anything on the boiler itself. My parents and in-laws say that it is also not possible on their boilers, so I hope this is not entirely unusual.

The technician said: He can turn this controller off completely, but that would mean that nothing would be controlled anymore and then hot water would run to the radiators 24/7, which for some reasons that I can’t fully recall right now, is at best an emergency solution and would also cause us significantly higher energy costs.

Why do we basically have to replace the heating system after 30 years? Is that legally mandatory? Definitely? Why do it if the heating system still works? But there are still 7 years left... According to the technician, a well-adjusted boiler can last forever, it didn’t sound to me like it definitely has to be replaced in 7 years.

The burner is brand new right now – but that doesn’t have to be replaced in 7 years??

And yes, I generally see this as somewhat critical when you say, tough luck, whoever gets up at half past four has to sit in a cold apartment. We care about a good rental relationship and of course want the tenant to be satisfied. Still, we also have to make sure we don’t have a money printer running here. The problem for this case is certainly, and we simply didn’t realize before: There are no two heating circuits and whatever we set for ourselves or for her applies to the entire house from top to bottom, also regarding the costs incurred.

I understood the technician like this: At the moment, since this control computer is broken, we can do nothing. Buying a new control system would initially cost around 1500 euros. (Regarding this: If we have to completely ??? replace the heating within the next 5 years at the latest, would this control system then no longer be usable??) Then we could set via time that the heating restarts at 4:15 a.m. and the tenant has 22 degrees or something. (Addition: Cold is always relative. At 10 p.m. she had 20 degrees and said that was too cold; I myself walk around here in the living room with a t-shirt at 21 degrees) Only: then everyone has that. Either we turn our own radiators completely off but then it’s very cold for us too, or the entire main house is reheated from 4:15 a.m. Everyone is still asleep then. That is economically completely nonsensical for us.

For us it would be enough if the heating turns on again in the main house at 6:15 a.m., but the tenant is long gone by then.

But if the heating kicks in every day 2 hours earlier during the heating season, what would that cost roughly per year? Are we talking about 50 euros per month, or 10, or 200?

What kind of boiler is this and the defective control system?

So: type, numbers, letters, etc.

Are these radiators or underfloor heating? If radiators, do they have their own thermostat? If a thermostat is present, then I would simply replace it with programmable ones. By the way, wasn't it said at some point that night setback can actually cause increased consumption?