Tracking down a central heating system leak

LRoss

Rwill wrote: »

I see this is an old thread but would appreciate advice. Have Worcester cdi boiler, installed just a year ago to previous owner.brand new house finished June 2013. I've only had the keys to the house for 4 weeks. Worcester engineer came out today under warranty as boiler totally loses all pressure everyday, goes from2 bar to zero in a matter of hours and then error code for over heating. He isolated the boiler from CH, pressure stayed constant, as soon as he reconnected went from 2.5 to 1.5 immediately. Then 1.5 to 1 in the next 30 mins. Left saying sorry love, not your boiler and good luck by the way, you've bought a poorly built house here. Helpful, not!! I asked him specifically about the expansion vessel but he said definitely not, must be a leak in the pipe work.

I have marble floors and tiled floors through the house so do not want to taking up the floor at all. My electric underfloor heating doesn't work in one bathroom either- could this be linked ie some pipe work damaged below the floor. The new house is still painted magnolia everywhere with white ceilings and there are no leaks visible anywhere, no leaks from the copper pipe outside, nothing from radiators (he bled them all). Could it be the heat exchanger on such a new boiler? Would this allow the pressure the drop so quickly?

As a woman who lives on her own it's easy to get really bamboozled by technicians and have been unimpressed with Worcester so far. Many thanks.

Hi, I just wondered how you resolved this problem as I'm having a similar issue! Any help would be great, thanks!

crazylady100

Hi
The camera the company I used actually sees through the floor without pulling it up. I know that sounds crazy but it detects tiny differences in the temperature of the floors or walls so that they can track the pipes and see if there are areas where the heat spreads out, indicating a leak. Then they have a little telescopic camera that can go through the smallest of holes to make an inspection if they need without taking up the floor.
The dropping pressure on our boiler was found to be a leaking pipe under the floor and they found it no problem. Luckily it was under a carpeted area, not under the tiles in the hall like we had thought, so they were able to just pull back a bit of carpet and lift a floorboard to get at the leak.
They were called The leak team. Search them online, I think they cover most of the UK.

LRoss

crazylady100 wrote: »

Hi
The camera the company I used actually sees through the floor without pulling it up. I know that sounds crazy but it detects tiny differences in the temperature of the floors or walls so that they can track the pipes and see if there are areas where the heat spreads out, indicating a leak. Then they have a little telescopic camera that can go through the smallest of holes to make an inspection if they need without taking up the floor.
The dropping pressure on our boiler was found to be a leaking pipe under the floor and they found it no problem. Luckily it was under a carpeted area, not under the tiles in the hall like we had thought, so they were able to just pull back a bit of carpet and lift a floorboard to get at the leak.
They were called The leak team. Search them online, I think they cover most of the UK.

Thanks! Looks like our insurance has track and trace cover should it come to that but fingers crossed it's more simple.

bigbandbossa

Hi

I also came across this old thread today and have found it very useful. Here’s where I am.. maybe try this test yourself.

I am currently topping up my approx 10 year old Worcestor Bosch 24i boiler every day to make it approx 1 bar. This is just on the low end of the green “normal” band of the indicator (there is a red “low” level and a red “high” level also on the indicator).

I then turn the room thermostat up so that the boiler fires whilst I’m watching the indicator. It rises rapidly to over 3 bar, well inside the red “high” level. At this point I look at the copper pipe on the outside wall and see water dripping out. This makes sense – the pressure relief valve is doing what you’d expect it to do, ie: letting out water to reduce the pressure.

I then turn down the thermostat so that the boiler switches off. As it cools I see the pressure dropping down. Pretty sure that in a few hours it will have dropped to way below 1 bar due to the loss of water.

So my next step is understanding what is causing this high pressure rise during firing... hoping google will help me as Homeserve who were here a few hours ago were useless. “You’ve probably got a leak under the concrete floor” without any investigation. Would love to go back to them with a proper diagnosis.

bigbandbossa

I've found an article with exactly the same symptoms but the forum won't let me post the link.

Google for "Worcestor Bosch 24i pressure problem screwfix expansion vessel" and you'll find it

HomeServe_company_representative

Good afternoon,

Thank you for the information you have provided and we would like to look at this so we can discuss the issues you are having. If you go onto our profile it will give the contact information so you can get in touch with us. Please send us your contact details and we can see what we can do to try and help.

Speak soon

Rebecca
Here To Help Team

LRoss

As it turned out, we had a faulty heat exchanger which was luckily still covered by Worcester-Bosch. Although our boiler is 8 years old, the part us guaranteed for 10 years. The burst heat exchanger had also soaked the burner so they replaced that as well.

southcoastrgi

bigbandbossa wrote: »

Hi

I also came across this old thread today and have found it very useful. Here’s where I am.. maybe try this test yourself.

I am currently topping up my approx 10 year old Worcestor Bosch 24i boiler every day to make it approx 1 bar. This is just on the low end of the green “normal” band of the indicator (there is a red “low” level and a red “high” level also on the indicator).

I then turn the room thermostat up so that the boiler fires whilst I’m watching the indicator. It rises rapidly to over 3 bar, well inside the red “high” level. At this point I look at the copper pipe on the outside wall and see water dripping out. This makes sense – the pressure relief valve is doing what you’d expect it to do, ie: letting out water to reduce the pressure.

I then turn down the thermostat so that the boiler switches off. As it cools I see the pressure dropping down. Pretty sure that in a few hours it will have dropped to way below 1 bar due to the loss of water.

So my next step is understanding what is causing this high pressure rise during firing... hoping google will help me as Homeserve who were here a few hours ago were useless. “You’ve probably got a leak under the concrete floor” without any investigation. Would love to go back to them with a proper diagnosis.

Expansion vessel is either faulty or needs re-pressurising

gotes

Useful advice in this thread! I was about to chuck some "leak sealant" stuff into my system, but after reading this I should definitely check my expansion vessel and PRV first.

crazylady100

I remember the guy we saw was dead against the leak sealant when we suggested it. He said it is usually just a temporary 'sticking plaster' which will often fail again a few months or years down the line and then in the meantime it stops people like him from being able to track down the actual leak to get it fixed properly. Just thought I would mention it...