ᐅ New Construction Underfloor Heating System with Heat Pump is Losing Pressure

Hello everyone,
I noticed a few weeks ago that the underfloor heating system is losing pressure. The first sign was the heat pump (HSPE Daikin) showing errors. Afterwards, I saw that the water pressure in the boiler dropped below 2 bar. After consulting with the heating technician, I topped up the water and increased the pressure to 2.7 bar. After about 6 weeks, it has dropped back to around 2 bar.
This means the underfloor heating loses about 0.1 bar each week.
Question:
Is this normal?

In summer, the underfloor heating probably isn’t running. Could this be related? Should I expect a leak?
Thank you for your answers.

The pressure has to go somewhere. Have you checked the heating circuit distributor?

Maybe there is also a wrongly adjusted or faulty safety valve releasing pressure into a drainage pipe?

But overall, that’s quite a lot of pressure, something isn’t right. Have the installer come and take a look!

I suspect a faulty (leaking) expansion tank.
However, if the homeowner isn’t even sure when the underfloor heating is running or not, I strongly recommend staying away from the system.

Additionally, since this is a new build, the installer should fix this issue free of charge.

immermehr schrieb:

Afterwards, I noticed that the water pressure in the boiler drops below 2 bar (29 psi).

Which boiler? It’s a heat pump, so why is there a boiler?

immermehr schrieb:

After consulting with the heating technician, I refilled water and increased the pressure to 2.7 bar (39 psi).

Wow! Normally, the heating system should operate around 1.5 bar (22 psi).

immermehr schrieb:

Question:
Is this normal?

No!

immermehr schrieb:

In summer, the underfloor heating probably isn’t running. Could it be related? Should I expect a leak?

But the pressure is still present in the system. And hot water is also produced with it.

immermehr schrieb:

Should I expect a leak?

Either there is a leak or water is escaping through the safety valve. It depends on what kind of safety valve is installed. After all, you are running a very high pressure of 2.7 bar (39 psi).

Sorry, I think:
- it’s just an expansion tank (instead of a boiler).
- I mixed it up. It is 1.5 bar instead of 2.5 bar.
I don’t see any dripping at the heating circuit distributor or at the tank.

I have now reported it to the builder. They should check it. Let’s see how it goes.

That’s exactly the MAG I meant. However, I would have expected a plastic container instead…