ᐅ Turn on the underfloor heating at the thermostat/controller.

Offtopic schrieb:

The actuators are missing here. Or the heating engineer has a plan and only performed the hydraulic balancing using the valves.

I wouldn’t use any actuators if the upper floor is going to be heated continuously; instead, I would set them manually. Of course, this only works if the heating curve is correct; otherwise, you’ll have to lower it until it fits.

The blue caps are basically temporary covers or manual controls. The further you turn them in, the less flow you get. Fully open is at the very top or the "off" position.

I would start by opening all of them fully and then observe how everything behaves. Especially check if the ground floor still gets enough flow in all heating circuits. If anything is off: reduce the flow slightly where there is too much and wait another day, etc.

If necessary, do the same for the heating circuit distributor on the ground floor if the valves there are also throttled too far.

I can report that I opened the cold and hot water pipes. Then there was a lot of water noise and gurgling, and now everything has stopped working. The error message is F 532: Flow rate too low.
It is a Vaillant heat pump. I’m not exactly sure which model.

The installer is coming Thursday or Friday. What a nuisance. I didn't realize that turning on the heating system could be so complicated.

And just refill and check if there are any leaks?

But this installation already looks quite questionable. Why is nothing insulated? Is the person who installed it back then coming?

Bertram100 schrieb:

Then there were lots of water noises and gurgling, and now everything has shut down. The error message is F 532: Flow rate too low.

I don’t know the hydraulics or the wiring diagram, but it probably just “choked.” After three years of inactivity, there was likely no pressure left in the system, but some air had entered here and there. Now the water pushed into the circuit, flushing out all the air—that’s why you heard the gurgling. This caused large pressure fluctuations or too much air at the heating pump, which triggered the fault. If there is still enough pressure in the system (usually more than 1 bar), I’d suggest clearing the fault and restarting the heating. If the flow rate is still too low, the system will shut down again because something is wrong.

The pipes I opened turned out to be the ones leading to the radiator in the bathroom. However, there isn’t a radiator installed there, so water spilled onto the floor. It’s a wooden floor as well, which makes it even worse.
Now the error message about insufficient flow rate makes sense.

I really hope the plumber can fix everything properly.

Bertram100 schrieb:

I can report that I have opened the cold and hot water pipes. Then there was a lot of water noise and gurgling, and now everything has stopped working. The error message reads F 532: Flow rate too low.
It is a Vaillant heat pump. I don’t know the exact model.

The installer is coming on Thursday or Friday. What a hassle. I didn’t know starting up the heating system would be so difficult.

I am quite familiar with this "problem" from the Panasonics. It regularly occurs during commissioning.

1. Increase the pressure in the heating circuit significantly. Preferably above 2 bar (29 psi).
2. Bleed the system wherever bleeding is possible (Panasonic systems have a bleeding program, also bleed at the heat pump).
3. Start up and enjoy when it gets warm.

Basically what @dertill also says.