Boiler Pressure - should I be worried?

Holt95

My boiler pressure is all the way to the max/top of the red.

I have turned off the boiler to be safe.

I have bled all radiators to no avail.

British Gas serviced it about a week ago saying everything was perfect - they've presumably cocked up somewhere as never had an issue before.

They won't be coming to sort it for a few days. Besides no heating in a very cold house, should I be worried about the high pressure despite boiler being off?

Thanks.

Neil_Jones

Normally bleeding a radiator and it doesn't reduce the pressure means there was no air in the system so all that's left is water. You should be able to continue to bleed the radiator until water starts coming out, obviously it should go without saying this can get messy and you shoudl really do this from cold, unless you want to visit A&E for scalding.

Failing all this you should be able to find a drain release valve, or there should be an overflow if there's too much water in the system. Rest assured your boiler's not going to explode or go shooting off into the sky like you might have seen on Mythbusters and similar, it was clear on those programmes the safety mechanisms were disabled.

Takmon

Holt95 wrote: »

My boiler pressure is all the way to the max/top of the red.

I have turned off the boiler to be safe.

I have bled all radiators to no avail.

British Gas serviced it about a week ago saying everything was perfect - they've presumably cocked up somewhere as never had an issue before.

They won't be coming to sort it for a few days. Besides no heating in a very cold house, should I be worried about the high pressure despite boiler being off?

Thanks.

Just open up one of the radiator bleed valves and let water out until the pressure reduces and then use the boiler again as normal. If the pressure increases again make sure the water inlet valve is closed.

matelodave

Have you got a combi boiler?
Check that the top up is turned off and ideally disconnected
Bleed a rad until the pressure is normal and everything should be OK

If it increases again then there might be an internal leak inside the boiler which is allowing mains water to pressurise the heating circuit

coffeehound

Holt95 wrote: »

My boiler pressure is all the way to the max/top of the red.

Is there a number next to the maximum pressure you have? Perhaps a professional can confirm, but AIUI the pressure relief valve should stop the pressure going above 3 bar. If it is going above 3 bar then the pressure relief valve could be faulty and need attention.

Mr_S_in_Easton

Bleed valves in rad.s let out a tiny amount of water (strictly speaking, it's not just water - there'll be various additives in with the water...), compared with the drain. Remember the whole central heating system is a closed circuit of pipes - look around for the drain, which will usually be at the lowest point of the whole circuit - think floor level. Prepare by checking you have: the right tool to open - and close! - the drain !!!!, containers for water and towels to mop up the spillages. Then simply use the drain to drop the pressure of the system until the dial on the boiler is back in the green zone.
Before you carry out the above, check to see the filling loop is closed.
If you don't get the above advice (no shame in that!), simply wait 'till the plumber comes, instead of risking a minor calamity. But don't be too scared - it's only water, after-all... even a big spill will dry up sooner or later!
Remember that boilers are fitted with relief valves so that if the pressure exceeds a certain value, the extra pressure will result in the water exiting the system via the relief valve, so there's need to worry about it all 'blowing up'!
CAVEAT: gas boilers are a cunning mix of water, flame and leccy, so if you don't know what you're doing, be careful! As a precaution, make sure you have the instructions for the boiler at hand and turn off the electric supply to the boiler, before doing any fiddling with the boiler itself.
BEST BET: retire to bed, wrap up in duvet, binge-watch the excellent gritty French cop drama, Spiral, on BBC4 - time will whizz by and before you know it, the gas man will be knocking on your door...