Newly built single-family house, first occupancy in Impflingen

Unfortunately, my wife and I are complete laymen when it comes to the topic of heat pumps.

Being a layman is not a problem. There are many experienced people here, but they all have one thing in common: they are not on site with you. And the optimal adjustment of the heating system with a heat pump cannot be done remotely. Therefore, I recommend that you contact a friendly master craftsman with knowledge of the products, make a maintenance contract, and tie the condition that the system is perfectly adjusted for the first time and that you receive an instruction. It should be possible to get a selection of such specialists through the manufacturer of the heat pump.

Isn't the developer obligated to ensure flawless operation of the heat pump at first occupancy and under the contract for work - upon handover of the property? Can I approach the seller and not demand this? If it is not possible, I would of course directly conclude a maintenance contract with a heating engineer or similar.

Isn't the developer obligated to ensure flawless operation of the heat pump upon first occupancy and under the contract for work?

Heretical question: Is the heating broken?

Can I approach the seller and not demand this?

Haven't you even spoken to him yet?

Yes, but he is currently ignoring me. The heating system - as it is currently set - is not capable of heating the building to 21 degrees, even though it is set to 21. The current room temperature is displayed as "-". All the analog room thermostats are set to 21 degrees. Only the bathroom has a temperature of 22 degrees.

Yes, but he is currently ignoring me. The heating system - as it is currently set - is not capable of heating the building to 21 degrees, although it is fixed at 21. The current room temperature is displayed as "-". All the analog room thermostats are set to 21 degrees. Only the bathroom has a temperature of 22 degrees.

Manifold distributors for the underfloor heating all open (can you take a photo)? Just to mention a possible "problem". Just keep bothering him so that the heating works correctly.

Isn't the developer obligated to ensure flawless operation of the heat pump at first occupancy and under the contract for work when handing over the property?

Usually, there is an instruction during the handover. Once you have accepted the house, the heating system is initially considered accepted as well, and from that point on you are responsible, so incorrect settings are not a warranty defect.
Keep pressing the developer and arrange an appointment for adjustment and instruction.
If you know the people who carried out the heating installation, have one of them come directly and give them a good tip so that they give you instruction and adjust the settings again.
These are the annoying little things that can be quickly resolved with some communication and willingness to cooperate. Principled people who have a claim often get their rights too—if they are in the right. However, that takes much longer, costs good time, and is annoying.