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Plumberpro, Home Appliance Technician
Category: Appliance
Satisfied Customers: 634
Experience:  Heating and hot water heating appliances experienced
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I have gas central heating fired by a Glow Worm 30hx1 boiler.

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I have gas central heating fired by a Glow Worm 30hx1 boiler. There is a water leak in the radiator return system. I have a British Gas Home care central heating insurance. They have been unable to locate the leak even with using a thermal imaging camera. They will not investigate further but suggest a complete re-routing of the downstairs pipework linked to the upstairs pipework. For this they are quoting me a bill for £5689.
A plumber friend has suggested using FERNOX to seal the leak. Please advise me as to whether using fernox in the system will be detrimental to the gas boiler.
***** *****
2nd July 2014

Plumberpro : Hello . I will help . Just need to ask you a few questions

what questions do you want answering?

Plumberpro : Hi there . Are you there?
Plumberpro : .
Plumberpro : Hi . Speak to me before you do anything .

How do I speak to you?

Plumberpro : Hello
Plumberpro : Can I ask you how british gas know there is a leak on the return pipe work ?
Plumberpro : Hi . Just type into the box at the bottom
Plumberpro : .
Plumberpro : Hello . Are you there?

My house has an annexe to it. One central heating boiler serves both house and annexe. My son and I noticed that the water meter dial was going round quite fast when there was nothing being used, also the central heating tank in the roof was draining as the ball valve was operating. By switching off the central heating to the house the meter stopped turning and the ball valve in the roof closed. I called British gas under my HomeCare policy. They came with Dyno-plumbing but were not able to locate a leak but agreed there was one on the return pipes from the downstairs radiators in the house which pass into the annexe. There is no sign of a leakage to the upstairs radiators in the house as the downstairs ceilings are dry.

Plumberpro : Hello . Is it concrete floors downstairs and in the annexe?
Plumberpro : And is your boiler downstairs?
Plumberpro : Also . You say you switched off the central heating to the house . How was this done !
Plumberpro : .

The floors are concrete.


The floors are of concrete in the house and annexe.


The boiler is in the annexe.


The boiler has seperate controllers for the house and annexe which can be operated individually

Plumberpro : Can I just say I know someone who works for dyne plumbing and he went from working in a shop to going straight out with no training whatsoever. I'm not saying this person was the same but bear that in mind . Also , you said that the central heating to the house was turned off and the water stopped . How was this done?
Plumberpro : .

The Dyno-plumbing man operated the thermal imaging camera but it could not detect heat of the pipework because of the insulation under the floor. House central heating was isolated by switching off the central heating switch on the house programmer

Plumberpro : Hi . Even with the power off to the boiler, pump etc. if there is a leak the water should still leak out if there is a leak . Can you isolate the mains water going into the header tank ? Ie , is there a stopcock on the header tank. If there is and this is closed. The tank would drain if a leak is on the system.

Yes there is the ball valve on the header tank,. I slightly mislead you before because with the central heating to the house switched off there is still a very slight draining out of the header tank. But as soon as the central heating is switched on the leak becomes apparent and the meter dial rotates. Annexe heating and hot water is not affected by the leakage and can be run without any loss of water in the header tank.

Plumberpro : Ok . It seems you have a leak under the concrete . I take it the pipe work is buried in the concrete screed . Leak sealer is really just a temporary solution and it may not work if your leak is that bad .it normally works on pinhole leaks . You can try it . It won't damage the system . I would try it first .
Plumberpro : But . Really the only proper solution is to redo the downstairs pipe work . How many radiators are down stairs, in house and annexe?

Yes the pipes are buried in the screed and I know the sealer may prove inadequate but as you say it might be worthwhile.


There are 11 radiators in the house, 6 upstairs and 5 on the ground floor. and 4 radiators in the annex.


To redo the downstairs pipework in the house is what British Gas say is the only answer. It is not covered on my insurance therefore I am faced with the ghastly sum of £5689 to put things right.


I would like to finish for the night. I am 82 years old and am a little exhausted right now, can we continue in the morning

Plumberpro : Hi . I used to really like it when a customer had head a quod from british gas because they are upto 4 times more expensive than anyone else charges and I knew I would get a job. I also used to subcontract for them and many smaller companies do better work as they have their reputation to think of. I would keep the emergency cover and get someone else to do the job. That price they gave I would not even charge for a whole system including all the materials. .ask around for a good plumber recommendation , from neighbours and friends, of a plumber used more than once. Also it would really cut the price down if you offered to cut the screed yourself, or get someone in. .
Plumberpro : Sorry . It went on a bit .. We can continue in the morning
Plumberpro : Whatever you do get a few quotes. All the best , Toby

Good morning Toby, thanks for your sound advice. I have already sounded out one or two good plumbers. As I am going to gambol with a sealant, is FERNOX the one you would recommend?



Plumberpro : Good morning . yes fernox is a good one . Put upto two bottles 2 x 1 litre.. All the best with it . Toby ..if happy with your answers would mind please rating the question. Thanks
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