Pressure loss, drops visibly straight after topping up

Hi,

Looking for a bit of advice here. I've got a system boiler (cylinder in airing cupboard), installed 2 years ago and serviced last year. Everything was working fine, till I took a rad off for decorating and the pressure dropped quite a bit and we re-pressurised the system. Since then the boiler has been losing pressure. I've bled the rad that came off and things were normal for a while, but today the pressure has been dropping all day and I've only just topped it up again and watching the pressure gauge drop infront of my eyes.

I've done some research and wondering if the white expansion vessel is knackered or needs re-charging? I checked and it's a 25L ExtraVarem vessel made by Varem. Is this something I could do myself? I have a bike pump at home with a gauge. I did tap the vessel and it sounded hollow to me, but not sure if this is relevant.

I'm hoping this is something I can do myself, before having to call out an plumber.

I have recharged my own vessel in the past on a baxi combo boiler. I was fortunate enough to have a
Pump for bike shocks so was small enough to access the valve on the vessel. Worth trying if you are confident enough

It won't be a white one, that would be the one for the hot water cylinder, the heating one would be red. It might need topping up, but to confirm that, go outside and find the pressure relief pipe, it will be wet and have evidence of water discharge as the system heats up.

Ok, so things have moved on considerably in the last 30 mins!

I tried bleeding the rad again and isolated it with the lock shield and TRV closed. Repressurised the system upto the normal pressure 1.5-2 bar with the valve at the cylinder and a leak has appeared under the boiler itself, where the magnatec filter is. It looks like it's coming from a nut that is joining the pipes together, although I havent got a big enough wrench to try and tighten it. Now I don't know if this was due to something I did or was the reason for the pressure dropping all along, but we definitely did not see a leak earlier this evening.

I will definitely call a plumber in the morning, but I was wondering if our backup immersion heater in the cylinder would still work if there is no pressure in the system? The leak, as expected, has bled the system of pressure and I have turned the boiler off anyway but havent turned on the immersion heater in case it causes further issues, but would really like to have hot water and heating for the morning.

Any help would be greatly appreciated.

Yes the immersion heater only needs water in the cylinder and the heating side pressure is not relevant.
However the immersion will only provide hot water, it won't give you heating for the morning.
The exception would be a thermal store type system but i think you'd know if you had that.

John D v2.0 said:

Yes the immersion heater only needs water in the cylinder and the heating side pressure is not relevant.
However the immersion will only provide hot water, it won't give you heating for the morning.
The exception would be a thermal store type system but i think you'd know if you had that.

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Thank you John, I really appreciate your help at this time of night. I have some backup electrical heaters that I can put in the family rooms if for the morning. But just to double check, the leak that has opened up under the boiler, will not affect the immersion heater or our use of both hot/cold water?

Sard said:

But just to double check, the leak that has opened up under the boiler, will not affect the immersion heater or our use of both hot/cold water?

Click to expand...

Correct.
Nothing is guaranteed, but it would be very weird if it did affect it

thank you!