Hydraulic balancing of underfloor heating

Hello forum,

I am about to have the handover inspection of my house (new KFW70 build) and still have a few problems with my underfloor heating and hope you can shed some light on the matter.

For testing the underfloor heating (district heating), I set all room thermostats (manufacturer Berker) to maximum (scale from 1-6). It is not cold in the house now, but not as warm as I expected at full power. The temperature in the rooms also seems to vary. I have ordered a laser thermometer to measure the floor temperature, the delivery is still pending.

I opened the distribution boxes on the floors for inspection (see photo). The control valves all hang on the return side. The flow rate is adjusted by valves on the supply side. Here, however, all valves are set to 0-0.5L/min. I suspect that no hydraulic balancing has been carried out.

How can I, as the buyer, test the heating? What documents and certificates can I request at handover?
How is the balancing carried out for underfloor heating?

Thank you in advance!

I have to ask counter questions. Is the photo current? I'm not a heating specialist, but in my case, the actuator motors that are not electrically connected would block the heating circuit. So there would be no heating output at all. Can you remove the actuator motors? Then at least full flow should be present.

I have to ask a counter question. Is the photo current? I'm not a heating specialist, but in my case, the actuators that are not electrically connected would block the heating circuit. So there would be no heating output at all. Can you remove the actuators? Then at least full flow should be present.

No, the photo is not current. Sorry for the confusion! All the actuators are electrically connected. The picture was only meant to give an overview.

but for me, the electrically not connected actuators would block the heating circuit.

Then they are switched "closed" without power! Usually, "open" without power is also possible!

v.g.

Hello,

... I ordered a laser thermometer to measure the floor temperature, the delivery is still pending.

The FB surface temperature is completely irrelevant, as the RT is the target and control variable.
Which OFT or supply temperature achieves this depends on the dimensioning of the heating surfaces!

... I suspect that no hydraulic balancing has been carried out.

The suspicion is fully justified!

... What documents and evidence can I request upon handover?

Heat load calculation including room heat loads according to DIN 12831, if controlled residential ventilation: air volume plan according to DIN 1946-6 and measurement protocol, heating surface dimensioning according to DIN 1264 (underfloor heating) and hydraulics!

... How is balancing carried out in underfloor heating?

By adjusting the volume flows based on the calculation (heating surface design). Whether suitable flow meters were used should be answered by the TGA planner.
In district heating, there is a transfer station. The energy delivered is measured on the primary side so that the transmission loss remains on the user side.

Regards

Hello, The FB surface temperature is completely irrelevant, as the RT target and control variable is. With which OFT or flow temperature this is achieved depends on the dimensioning of the heating surfaces!

OK thanks. What options do I have as a layperson to check the proper functioning of the heating system? My Berker room thermostats have a setting range from 1-6, which is supposed to correspond to 5-30° degrees. Currently, I have just under 20° throughout the house when all controllers are set to 6. Is there a maximum room temperature that the heating system must reach? The developer presented me the heating protocol of the screed, as I had doubted it. According to my understanding, the hydraulic balancing should have already taken place before the functional heating of the screed. The now confirmed flow temperatures probably only existed in my basement, the heating circuits were hardly warmed because of the turned-down flow restrictors. Many thanks for the expert information!