ᐅ New bathroom radiator just won’t heat up

Created on: 6 Dec 2024 19:02
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Rol_Rom
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Rol_Rom
6 Dec 2024 19:02
Hello everyone,
I have an air-to-water heat pump from Stiebel Eltron, manufactured in 2013.
Recently, I had to replace a bathroom radiator in the attic due to corrosion at the connection fittings.
The new radiator (towel warmer) was installed, the system was refilled and vented. New water was added to the system at 2 bar (29 psi), as before.
Since the radiator didn’t warm up, I loosened the valve head and checked the pin for free movement. Everything seemed normal, but I sprayed Ballistol on it anyway.
When that didn’t help, I initially increased the flow rate at the radiator manifold (the radiator is connected—like another one on the ground floor—to the underfloor heating system), but unfortunately, that didn’t work either. (I now know this setup isn’t ideal, but it had been working fine until now).
In the meantime, I also replaced both the supply and return valves—again without success.
The other radiator on the ground floor and the underfloor heating throughout the rest of the house are working fine.
What else can I try? I’m pretty much at a loss right now.
J
Jesse Custer
7 Dec 2024 07:07
What I find missing in your list is that you also fully opened the flow valve in the radiator.

Or did you mean the "supply and return valve"?
R
Rol_Rom
7 Dec 2024 10:25
Jesse Custer schrieb:

What I find missing in your list is that you also fully opened the flow valve on the radiator.

Or did you mean that by "supply and return valve"?

Hello Jesse,
By supply and return valves, I meant the ones on the heating manifold.
On the radiator, I opened the thermostat valve! I don’t have any other valves.
J
Jesse Custer
7 Dec 2024 13:01
I thought so.

When you turn down the thermostat, the pin inside moves out – this basically controls the reaction based on the temperature setting on your thermostat.

However, beneath that is the actual radiator valve, which controls how much volume flow passes through.

Try searching for "doing hydraulic balancing yourself" in any search engine – you’ll then see the actual valve located UNDER the thermostat. It is probably fully closed at the moment... it’s often red and has numbers on it... try turning it up a bit.

But be careful: don’t adjust it too much, as this also affects the flow throughout the rest of the house!
R
Rol_Rom
7 Dec 2024 16:44
As I mentioned at the beginning:
“Since the radiator didn’t warm up, I loosened the valve head and checked the pin for movement. Everything seems normal, but I still sprayed a burst of Ballistol on it.”
And the setting: see photo
Filling also worked by opening the valve…
Close-up of a rusted brass component with an orange gasket and a central screw shaft.
R
Rol_Rom
7 Dec 2024 16:59
I could kick myself:
The return line can also be shut off opposite the inlet valve, and I had apparently closed that as well.
But I thank you for your efforts!
Rusty copper pipe connection with hex nut; floor tiles visible