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

jehd schrieb:

I would strongly recommend checking the manufacturer’s manual. This is not a "standard" setup. The adjustment screws under the orange caps are flow restrictors. According to the manual, the set maximum flow remains unchanged even if you adjust other heating circuits.

You can base your settings on the current balancing, but this can cause problems if all circuits are restricted too much. My heating technician had the circuits reasonably adjusted, but so that the required flow was only reached with a 10-meter (33-foot) pump at maximum (150 W power consumption continuously). By readjusting, I was able to reduce this to a 3-meter (10-foot) pump setting, which led to significant energy savings.

Therefore, I wouldn’t just adjust the circuits relative to each other but also open them as far as possible overall to reduce the pump’s resistance.

Thanks. That’s why I shared the YouTube link here in the first place. But what does all this mean in practice?

I mentioned that I have fully opened all the valves under the orange caps. So, the maximum flow should be set. What do your comments mean for the flow meters?

The other tips are generally fine, and the minor differences are not that important. But you’re asking about the specific implementation. For that, I recommend systematically understanding what an adjustment in the settings actually does. Then it suddenly becomes simple.

For this:

• As mentioned above, only change one thing at a time and keep a logbook. It can be brief but should include the change, the reason for the change, and afterwards the outcome (worked/did not work, probably because...).
• Check external influences. Especially the heating pump. For example, it can be set to "constant pressure" or "constant volume." Throttling a heating circuit would yield different results depending on this. Because in one case, with constant pressure, higher resistance would reduce the overall flow. In the other case, the pump would work harder and the total flow would remain the same but be distributed differently between the circuits. The pump could also be dynamically regulated. None of this rules anything out, but it must be considered to understand the effects of changes.
• Check/understand the function of a controller. If everything is fully open, I assume the flows are limited by the physical resistance (pipe length, etc.). So if the controller only limits maximum flow, you should be able to throttle it without initially changing the flow. Only when the maximum set flow is below the “natural” unrestricted flow should it decrease. You can observe this on the flow meters (at first, no change when throttling, then from a certain point the flow decreases continuously), even if you can’t read exact values yet.
• If that’s the case, you can determine the natural flows this way. Set each controller to its limit and read the value on the adjustment screw. Then you can check whether the sum of these flows (-> table in the manual) matches what the heating system shows. That would mean the flows are quantitatively understood.
• If so, you can also use the values at the adjustment screw to create a scale for the flow meters (what reading corresponds to which flow). But this is actually not necessary because you can then read the flow directly from the controller (but only as long as it limits the flow, i.e., up to the natural flow).
• Watch if adjusting one circuit changes the flow in the other circuits.

If all of this is correct—I’m only guessing based on the manual—then the function would be well understood, and it would be easier to balance your system than with regular valves, because you could throttle one heating circuit without affecting the others.

I would first set all controllers to the natural flow as a starting point, meaning just before any reduction (-> logbook values).

Then fine-tune the heating curve and/or pump until you reach the limit in the coldest room.

Then throttle the circuits individually and monitor whether the flows in the others really do not change and keep an eye on the total flow shown by the heating system.

Thank you for the very detailed tips. To me, it all sounds incredibly complicated and time-consuming, and I don’t fully understand the details, but that’s on me.

Maybe it’s better to just have the company that installed the system come over and go through everything together. I’m starting to think that might be the more practical approach for me personally 🙁

It's not difficult. You just have to be systematic because after each adjustment, you have to wait a long time to see the effect since the underfloor heating system reacts very slowly. I then forget what settings I applied a few days ago and have to guess, which is inefficient. But you soon figure out how it works (what each change does), and after that, it just requires some patience.

That's why hiring a company only helps to a limited extent. They come once and set the calculated values. You don’t want to pay them to come back every few days until it's properly adjusted.

jehd schrieb:

It’s not difficult. You just have to approach it systematically because with radiant floor heating, you have to wait a long time after each adjustment to see the effect since it responds so slowly. I tend to forget what I set a few days ago and have to guess, which is inefficient. But after a while, you figure out how it works (what the changes cause), and then it just takes some patience.

That’s why hiring a company only helps to a limited extent. They come once and set calculated values. You don’t want to keep paying them to come every few days until it’s properly adjusted.

That may be true, but I have so many questions just about your text that I could then ask the professional company and have them show me exactly where and what to adjust.

I don’t know where to find the pump settings, I don’t understand the consequences of each setting or what results from them, I have no idea how to verify your assumptions about the property, I don’t know what you mean by “natural flow,” and which controllers you’re referring to at all (top meters? The ones under the orange cover?), and so on.

And I also can’t keep bothering you nice people forever.

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

If the heating circuit can physically allow a maximum of 10 liters per minute (2.6 gallons per minute) due to the parameters mentioned above, you can set the top meter to 20 liters per minute (5.3 gallons per minute) without any positive effect on the flow. You can effectively "throttle" this circuit as much as you want without seeing any result until you drop below the 10 liters per minute (2.6 gallons per minute) threshold. Only then will the amount of heat delivered to this heating circuit change.

I want to reassure you: as long as you document everything reasonably well, you can’t break anything. If something goes wrong, the heat pump will sometimes go into fault mode, and you can simply revert your last setting. This is learning by doing. A company will usually just come, set it so that it gets nice and warm, without caring much about the consumption. Many companies honestly lack the knowledge and interest in these topics.

It is highly recommended that you educate yourself step by step.