Hydraulic balancing, disable single room control?

Hello everyone! Since the heating season is slowly but surely starting again, I wanted to gradually start adjusting our heating system (Viessmann Vitodens 200W 13 KW). We built a KFW 55 house with underfloor heating.

Now I keep reading about the hydraulic balancing. I would like to check and readjust it! Our heating installer was very diligent... but no more than that! That’s why I want to check everything myself.

How do I adjust the hydraulic balancing? I set all room thermostats to full power (room temperature for example 30 degrees) and then I look at the “sight glasses” on the hydraulic balancing valve and bring them all to the same flow, or have I misunderstood something?

Since we have a weather-compensated system, does that matter?

If the balancing is correctly set, how do I proceed?

I would like to deactivate the ERR. How do I do that? Can I simply unplug the motors? Are they then fully open?

If the ERR is deactivated (however that works...) how do I then control the room temperature? Solely by the heating circuit flow (or return?!) temperature of the heating system?

I would like to keep the weather-compensated control (is that possible?!). Then theoretically I would have to adjust everything else by the heating curve, right? How does that work?

It would be great if you experts could give me some guidance.

Basically write down all current values.

Then shut down all err.

Deactivate additional heaters.

Lower the heating curve on the heater until it gets cold; this will probably happen first in the bathroom.

Currently, 30/24/0 will probably be sufficient.

Then reduce the flow on the Tacos until the desired temperatures are reached in the rooms.

Be careful, multiple heating circuits can be responsible for one room.

Check this procedure daily to exclude solar heat input.

Make sure that the minimum flow rate of the heating system is not undershot; it is stated in the data sheet.

If you have enough flow, you can reduce the power on the heating circulation pump.

This is roughly how to proceed.

If that works, write down the return temperature over time; after about 2 minutes, the supply temperature must not yet be reached, etc.

You need to try to increase this supply-return spread in order to achieve high heat output.

Can I simply unplug the connectors from the motors? Will they then be fully open?

Normally it’s written on them, NC means normally closed without power, so you have to lift them. Until recently, I also just turned the controllers fully up because I wasn’t sure.

If the ERR is deactivated (however that may be...) how do I then regulate the room temperature

not at all, I haven’t touched them for months.

I would like to keep the weather-controlled regulation (is that possible?!).

What else should that be than a heating curve that says at 10 degrees the return flow should be e.g. 25 degrees? But 13 kW is quite a lot but normal for a gas heating system?

Ah another one I think we’ll have to start a support group or a FAQ here soon.

Quite a few things have already been said.

But my advice to you: Don’t do it (yet) and wait until it gets cooler. At the moment the temperatures outside are still going up and down, you’ll do more harm by fiddling with it than good.

Since we have a weather-controlled system, does that matter?

Well yes, nowadays every new build usually has that. That was basically assumed here. But just as a side note.

I would like to deactivate the ERR. How do I do that? Can I just unplug the motors? Will they then be fully open?

The best thing is to simply take them off completely.

If the ERR is deactivated (however that may be...) how do I then regulate the room temperature? Only via the flow (or return?!) temperature of the heating?

Actually not at all, the boiler does that for you. Once you have everything set correctly, you will always have stable temperatures in the rooms. Maybe a bit more or less than X degrees, just as you set it. The temperature you want to reach is set by the flow rate, but be very careful and only adjust minimally. One full turn can possibly be far too much. So leave everything as it is without the actuators for a few days and observe. But wait a week or two longer. It’s still too warm outside.

But 13 kW is quite a lot but normal for a gas heating?

Yes, it is, but it also modulates down just like a heat pump. Just not as far down... but it doesn’t have to.

Not at all, I haven’t touched them for months.

I top that, haven’t touched mine in 8 years.

I have the same condensing boiler and the heating technician left all settings at standard. Then I adjusted the heating curve myself. However, I haven't been able to test it yet due to insufficiently warm temperatures.

I also noticed that the boiler cycles too frequently. For better monitoring, I installed on-wire sensors on the supply and return lines. Here is an excerpt from March of this year. The problem is certainly also that the heating system does not know the current heat demand. Possibly I could also lock the boiler (potential contact or similar) with my own logic?

I definitely still need to perform the hydraulic balancing.

Actually not at all, because the boiler does that for you. Once you have everything set correctly, you will always have consistent temperatures in the rooms. More or less degrees X just as you set it. The temperatures to be achieved are set according to the flow rate, but proceed very carefully here and only adjust minimally. A whole turn can sometimes already be much too much. Therefore, first leave everything as it is without the actuators and observe the whole thing for a few days. But wait another week or two. It is still too warm outside.

Although it must be said that what works in cold weather does not necessarily have to work during the transition period.
By default, a slope of 0.3 was set for me.
I also started adjusting in autumn and managed it well. In winter it was then much too warm. So I set the heating curve lower until it fit again. In spring it was then too cold again. I then went down to 0.2 and shifted the height a bit and then it worked in the following year as well, so that I completely deactivated the ERR. I think in that year my wife cursed me ops:, because I forbade her to mess with the remaining ERR.

In my opinion, it is a process of approximation and no heating engineer can do that for you.