Replaced bathroom radiator towel rail - now getting low water pressure safety switch off message

mrauspicious · 2 Apr 2025

Hello

I replaced a heated towel rail/bathroom radiator today. Switched off the central heating, closed the valves, hung and fitted the new radiator. I opened the bleed valve at the top of the rad, opened the two valves and turned the heating on. I’m getting an F22 message from my Vailant combi boiler - safety switch off, low water pressure. No hot water out the taps. I have switch it off now

Any help gratefully received

mrauspicious · 2 Apr 2025

it’s a Vailant Ecotec plus 831

trojanhawrs · 2 Apr 2025

You don't turn the heating on until you've refilled the system. You'll need to fill the rad with water first, either filling with a jug from the top or using the fill loop on the boiler

mrauspicious · 2 Apr 2025

trojanhawrs said:
You don't turn the heating on until you've refilled the system. You'll need to fill the rad with water first, either filling with a jug from the top or using the fill loop on the boiler

Thanks

So I can take off the valve at the top and pour water into it until its full, replace the valve and turn the heating on?

oldbuffer · 2 Apr 2025

Just re-pressurise the system in the normal way, bleeding the new radiator in the process. How to re-pressurise will be in the boiler instructions, probably available on-line if you haven't got a copy.

Stuckinarut · 2 Apr 2025

As above, do it the normal way. You should have a braided hose to attach to x2 valves or perhaps already in situ, open one or both valves and take pressure to 1-1.5 bar and check rad is free of air, job done.

polesapart · 2 Apr 2025

The Plus has two grey valves underneath.

mrauspicious · 3 Apr 2025

Thanks for your help, I opened the two valves and repressurized the boiler until it reached 1.2 bar

Stuckinarut · 3 Apr 2025

mrauspicious said:
Thanks for your help, I opened the two valves and repressurized the boiler until it reached 1.2 bar

So does it now work?

mrauspicious · 3 Apr 2025

Stuckinarut said:
So does it now work?

It does. One of the radiator valves is leaking now but that’s a different story

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Replaced bathroom radiator towel rail - now getting low water pressure safety switch off message

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