Combi-boiler pressure too high - over topped up

oniongirl

Hi, I wonder if someone can help us avoid calling out an engineer.

About every 6 months, we have to top up the pressure on our combi boiler. It's a simple turn a couple of valves jobby til pressure gets between 1 - 2 bar.

Unfortunately my boyfriend didn't turn the valves off quickly enough, and the pressure went up to 3.5 bar, and lots of clanging from the boiler and our radiators ensued, so we turned it off.

After a bit of googling, I decided that bleeding the radiators to remove some water would reduce the pressure - which it did. A jug of water later, and it was back to 1.5 bar. I followed the instructions in the user guide to turn the boiler back on, but it nearly immediately started clanging. Then the pressure gauge went up past the 'max' level, I got scared and turned the thing off again.

I went to bleed the radiator again, thinking it would take a bit to get it down again, but I hardly let out a few mls before the pressure returned to 1.5 bar.

Does anyone have any suggestions on how to get it up and running again? I'll admit I'm a bit scared of it blowing up in my face. I can't seem to see a valve to drain the water on the boiler - I understand it's under the casing and am not keen on taking the damned thing apart.

Thanks!

AVERAGEJOE_2

What Make of boiler ? Usually when pressure gets to high the prv pressure relief valve will pop off and save the boiler thats whats it is there for.
So drain down part of system and fill bleeding rads ect if needed.
Unfortunatly i have found once the prv has been activated they never really same again so means getting new one fitted.
Sounds to me like you have air in your system that causing your instant high pressure though.

oniongirl

Hi, thanks for your reply. It's an Ideal Logic+ boiler.

I tried turning boiler on again (don't know why, I'm ever the optimist) and after an initial pressure surge, the pressure settled at about 1.5 bar. When turning the heating on on the boiler though, the pressure jumps again to 2 bar and the radiators don't appear to be warming up.

Will I need to bleed them all, do you think? I wonder if draining off the water from just one has made things a bit iffy.

oniongirl

I've left it a while and radiators are still not heating up. The boiler is constantly displaying "pump overrun", which is normally only displayed for a short while after we've used the hit water, although, if I'm honest, I'm not sure I've ever looked at what the boiler says when the central heating is on.

As far as the boiler is concerned, the heating is on. There are no error messages. I might have to get an engineer in after all as I have no ideas now.

cyclonebri1

It's possible that instead of bleeding water out of thge rads you have inadvertently drawn air in.

bleed them all with the system off first of all then again once there is some warm up.

SGM1

Weird, sounds like some restriction. I'd check you didn't turn off one of the isolation valves on the central heating circuit by mistake when using the filling loop. They are usually on the opposite ends of the boiler.

littlerock

sounds like a possible heat exchanger problem (e recently had one) - plumber said they don't necessarily record a fault but keep failing to moderate heat generated and racing up to maximum then stopping. Has boiler been very noisy lately? Do you use it a lot on a daily basis? Do you live in a hardwater area? All true in our case

Seronera

Well.... You have broken it once, and it's only an expensive gas appliance. What could possibly go wrong if you fiddle with it some more seeing as you seem to know what you are doing.

On the other hand perhaps you should get somebody qualified to sort it out. Gas appliances are not toys. Your lives might depend on its safe operation.

Crinkmeister

Seronera wrote: »

Well.... You have broken it once, and it's only an expensive gas appliance. What could possibly go wrong if you fiddle with it some more seeing as you seem to know what you are doing.

On the other hand perhaps you should get somebody qualified to sort it out. Gas appliances are not toys. Your lives might depend on its safe operation.

Ooh! A bit harsh I feel!

Seronera

Crinkmeister wrote: »

Ooh! A bit harsh I feel!

But true I feel.You would not believe some of the things I find on gas appliances due to dangerous DIY.I have their best interests at heart, even if the truth hurts.

Also the more they fiddle with it the more damage they will do, and the more it will cost to fix. Somebody has to have the guts to tell them to stop digging the hole deeper than it need be. I'm qualified enough to be that person

Crinkmeister

Seronera wrote: »

But true I feel.You would not believe some of the things I find on gas appliances due to dangerous DIY.I have their best interests at heart, even if the truth hurts.

Also the more they fiddle with it the more damage they will do, and the more it will cost to fix. Somebody has to have the guts to tell them to stop digging the hole deeper than it need be. I'm qualified enough to be that person

Fair enough Seronera. Time for a proper boiler service by a GSR methinks.