Boiler Issue - Overpressuring

KeepOnRunning

Unfortunately I've got a boiler issue which needs sorting before it starts getting seriously cold.
I moved into the house back in March and I rarely needed the boiler on.

I turned the heating on the other day and the pressure shot up to 3.5 bar within 15 minutes, so I turned the heating off and decided to try again in a few days to see if it happened again.

I tried again today and within around 10 minutes the pressure was reading 3.4 bar, so I've turned it off.
Now (30 minutes after last turning off the heating) the pressure reads 1.6 bar.

I've tried releasing the pressure from the radiators, but upon turning the heating back on the pressure rises again. There appears to be no air in the system as all the radiators are all heating up quickly (within 5 minutes) and only water comes out upon releasing the pressure.
The boiler heats up water without a problem, and it has all the time I've been in the house.

This is my first house, and boiler issues are not something I've not had to deal with before! Should I call out a plumber or is there something else I can try?

It's a combi-boiler - Glowworm 30ci. A ten minute Google suggests an expansion vessel problem but as previously stated I'm no pro.

Thanks for reading.

Alex1983

It will be expansion vessel, get the boiler serviced and they will recharge the expansion vessel at the same time.

C_Mababejive

The expansion vessel could well be faulty

chappers

Alex1983 wrote: »

It will be expansion vessel, get the boiler serviced and they will recharge the expansion vessel at the same time.

Providing the diaphragm hasn't split, you can check this by pressing the car tyre type valve on the expansion vessel and if water comes out then its split.
Is water blowing off out of the pressure relief valve outside, if so that will also need replacing as I guarantee you won't be able to stop it leaking if the expansion vessel problem is fixed