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SteveCole

Hi,

I know this question has been asked elsewhere before, but I have a boiler issue that is driving me mad!

I live in a house that was built in the mid-70s. We had a new Worcester-Bosch Combi Boiler installed in October. From Day One it's been losing pressure, usually settling on around 0.8. I kept topping it up to 1.5, usually every 7-10 days.

However, it's since got a lot worse and this seems to have happened every time a plumber has gone near the boiler.

We keep getting told that we probably have a water leak somewhere and as it's not coming from upstairs it's more-than-likely underneath the floor, which is concrete and is nothing to worry about for the time being. However, I'm finding it strange that it keeps getting worse when a plumber does anything to it. It's now at a point that it goes to 0 every 1-2 days. We had Worcester out last week, and they couldn't find anything. He did say that if it got worse he could take the whole back off, but felt it was very unlikely to be the boiler.

The towel rail keeps needing to be bled, as it loses warmth but this hasn't worsened in tune with the boiler getting worse. I need to bleed this every 2 weeks or more. It hasn't become more frequent at all.

Any ideas? Are the plumbers right?

Steve
 
only one way to find out.

Isolate / disconnect the boiler from the system piping and test the system piping, to say - minimum 3 bars, for an extended period.

If that holds for a few hours, then there's a leak at or in the boiler.
 
Thanks. Sorry, my plumbing knowledge is zero. Is this something a numpty like me could easily do?
 
8/10 times its pipe buried in the ground floor, and tbh it needs sorting as topping it up every 2-3 days is bad for your system, as every time you top the pressure up it adds more air to the system and increases corrosion in your system

My recommendation is get/ find a different decent heating engy that is willing to find the leak
 
Welcome to the forum :)

Need to tackle logically.

Isolate boiler from system and see if you still get a pressure drop.

If it's the system then first try a leak sealer.

If this fails then you have two options.
Find and fix or
Repipe ground floor from upstairs.

My preference is the second. This is purely due to not knowing condition of underground pipework. You could fix a leak and then get another one down the line.

But as said, simply topping it up all the time is a recipe for disaster. You are continually diluting the inhibitor and adding oxygenated water to the system.
 
Buy the sound of it. There will not be any inhibitor left in the system. With how often it is being topped up.:(
 
What would the cause be of the pressure loss getting worse every time an engineer does anything to the boiler?

And, to drop down pipes from upstairs (there are only three radiators downstairs that would need to be fed from upstairs and they are all directly below upstairs radiators) what sort of cost would I be looking at? Thousands?
 
If you have a corroding joint in the concrete screed then these things have a habit of getting worse whenever someone makes big changes in the water pressure. Imagine a small pinhole in a joint under there, changes in pressure will make it worse. On top of this, every time you top up the water pressure you dilute the corrosion inhibitor chemical in the heating system.

A leak in a combi boiler will either be: -

1.) Coming out of the main heat exchanger, you will possible see this coming out the plastic condensate pipe on the bottom of the boiler (if it's dropping into a gully trap outside).
2.) Venting from the pressure relief pipework (should be a 15mm copper pipe turned back to the wall directly outside the house from the boiler). This will usually only be happening when the boiler is running.
3.) Visible underneath the boiler as a leak coming from the casing.

If it's none of these then you have a leak on the central heating pipework. There are companies such as ours that have acoustic leak detection equipment to find a leak under a concrete screed. It's very good but also quite costly. Also, if you have one leaking joint under the concrete, you will be finding more in a short period of time. If that turns out to be the cause you would be better off in the long-term running new pipework to the downstairs radiators from between the floors.
 
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