Central heating Question

[pete]

We have a combi-boiler which loses pressure when switched off, needing re-filling every day. It has always needed to be topped up but has got worse in recent months and for the last while it has needed to be topped up daily.

We are considering a new boiler but I need to resolve this first, I think?

It is so much water that I figure the following,
It can't be upstairs or we'd see the leak from below. We've looked under most of downstairs but there is a section which is not accessible from below.

Is it too significant a leak to ignore? I'm approaching the point of ripping up floors! The plumber is talking about making it easier to fill up but we must be putting a fair amount of water under the floor?

All I could think of was introducing stop cocks into the pipes to shut off areas so I can narrow down the leak? (But that's also adding chances to leak)

Suggestions?

[tut]

Buy a new house Pete, pass your problems on like we did, but lie your head off.

tut

[robin]

Do you accumulate air in the radiators?

I assume there are no snail trails around the boiler, e.g. expansion vessel pressure relief valve (unlikely if you're losing pressure when off).

I would ask another heating engineer for their opinion on finding leaks - there must be tried and tested techniques for doing this ...

Cheers,
Robin

[thinfourth]

If you are thinking of a new boiler then it must be old

It might be the heat exchanger that is leaking

[pete]

Tried all those.

The new boiler was to increase efficiency - boiler's about 8 years old but struggles to heat teh whole house when cold.

Expansion vessel checked etc. No air in radiators.

[tut]

...........or give MI5 a call.

tut

[thinfourth]

I would look at where the pump is in the system as you might find that lets you isolate one half of the system using the pump valves

Then find a way to blank off the other leg then you could isolate your boiler from the pipework

Then see if the boiler + expansion vessel are leaking

[robin]

Tried all those.

The new boiler was to increase efficiency - boiler's about 8 years old but struggles to heat teh whole house when cold.

Expansion vessel checked etc. No air in radiators.

How fast does the pressure drop if you pressurise when cold and leave the boiler powered off?

On a quiet day you might actually hear something in the pipes, if the pressure is dropping fast enough - try a stethoscope ... or ask somebody who does it for a living?

Cheers,
Robin

[David]

It's possible there's no leak - just the accumulator has filled up with water. This causes the pressure relief to vent when the water expands. The pressure then drops rapidly to below the minimum when it cools - and it never switches back on. A foot pump on the 'car' valve on the accumulator would push the water out and may fix it.

[tenkfeet]

Tried all those.

The new boiler was to increase efficiency - boiler's about 8 years old but struggles to heat teh whole house when cold.

Expansion vessel checked etc. No air in radiators.

I used to rent a room in a big old house and the boiler had constant issues from new, struggled to heat the house and losing pressure. Turned out the boiler was not powerful enough to heat the house properly. The constant topping up was due to the expansion in the system not being compensated for so the boiler would vent water every time it got hot, pressure then dropped when it was cool.

He sold the house and that was the least of the new owners worries.

[Dominic]

He sold the house and that was the least of the new owners worries.

You stayed on as a tenant?

[tenkfeet]

He sold the house and that was the least of the new owners worries.

You stayed on as a tenant?

I will have you know I was an ideal tenant most of the time.

[pete]

Tried all those.

The new boiler was to increase efficiency - boiler's about 8 years old but struggles to heat teh whole house when cold.

Expansion vessel checked etc. No air in radiators.

How fast does the pressure drop if you pressurise when cold and leave the boiler powered off?

On a quiet day you might actually hear something in the pipes, if the pressure is dropping fast enough - try a stethoscope ... or ask somebody who does it for a living?

Cheers,
Robin

I've asked someone who does it for a living! But they aren't being very helpful so I thought I'd turn to the SE crowdthiniking solution instead.

Honestly if we start only asking people who actually get paid to do stuff the internet will die!

Bloke 1 is still working on it.
Bloke 2 wanted to condemn the whole installation (wrongly, I checked)
Bloke 3 wouldn#t help.

Stethoscope is a good idea

[tenkfeet]

As its "still working" you could always get one of these boiler cover insurances, believe they cover the whole system. Wait a few months and bobs your uncle.

[woody]

As its "still working" you could always get one of these boiler cover insurances, believe they cover the whole system. Wait a few months and bobs your uncle.

They check them first. I have a similar issue to Pete's and hatched a similar plan to yours.