ᐅ How to Perform a Hydraulic Balancing of a Radiant Floor Heating System Yourself?

Joedreck schrieb:

The natural flow: each heating circuit has a maximum possible flow rate, which can be calculated based on the pump pressure, the length of the piping, and the pipe diameter. But you can also test it.

If, due to the parameters mentioned above, for example, the heating circuit can physically allow a maximum of 10 liters per minute (2.6 gallons per minute), you can set the flow meter to 20 liters per minute (5.3 gallons per minute) without it having any positive effect on the flow. You can basically "throttle" this circuit as much as you want without any result, as long as you don’t go below 10 liters per minute (2.6 gallons per minute). Only then will the delivered thermal energy to this heating circuit change.

I want to reassure you a bit: as long as you document everything reasonably well, you can’t do any damage. If something goes wrong, the heat pump will simply go into fault mode, and you can revert to the last setting.
This is learning by doing. A company often just comes, sets it so that it gets comfortably warm, but the consumption is totally irrelevant to them. Honestly, many companies don’t have the knowledge or interest in these topics.
It is really advisable to inform yourself step by step.

Thanks! Yesterday I spoke with my heating installer. He confirmed everything you said. The system regulates itself, so it constantly restores and maintains the set flow rate, even if you adjust other valves. Opening all valves wide doesn’t help, precisely because of the natural limitation. If you open everything fully, there might be too little water for a too-cold room, unfortunately.

The initial balancing was documented. I have now reset everything to that baseline and am slowly opening the valves where it’s too cool. Then I’ll adjust the heating curve downwards. By the way, only the valves are adjusted; the flow meters are only for reading.
Makes sense so far, right?

Yes, exactly. Just give it a try, it’s really not difficult.

However, watch the flow indicator while adjusting. The key is to see whether the flow actually increases when you open the valve or decreases when you close it. This will result in the desired change in the room temperature.

But it can happen that opening a valve does not increase the flow. In this case, the circuit is limited by the natural flow and not by the throttling of the valve. So, you cannot simply increase the flow by opening the valve, and the room will not get warmer. If this problem occurs, feel free to get back in touch.

Will do. I have now set the heating curve to 32°C (90°F) supply temperature at 0°C (32°F) outside temperature and increased the heating in the slightly cooler rooms. At the moment, I don’t notice it being cooler than with a higher curve. I can also see higher flow on the flow meter in the affected room. Let’s see how it develops.

What is actually an efficient supply temperature? Maybe 32°C (90°F) is already good? It’s a new build from 2023, not KfW standard, monolithically built with thermal bricks and no additional insulation.

With a heat pump, the goal is to operate at the lowest possible supply temperature while maintaining the longest possible running time. Frequent cycling should be avoided as much as possible.