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Tuvoc

Central Heating Boiler question !

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Maybe not the best place to ask, but I have seen before there are a couple of qualified engineers on here.

 

My boiler is an old Potterton Promax condensing boiler, in the kitchen downstairs, with the hot water cylinder in the bathroom upstairs and water tank in the loft, does hot water and central heating, the old traditional style system. 

 

If I have the hot water set to 24 hours on the timer control, everything is fine. It just comes on briefly every once in a while to keep the water in the cylinder up to temperature, and everything is bone dry. It runs well with no issues. BUT if I use the timer to have it come on for a couple of hours in the mornings and evenings, and OFF during the day and night, then it leaks. Water collects at the bottom of the boiler cabinet and then overflows onto the kitchen bench and I'll have a puddle of water. So I have to run it 24hrs, and also when I go on holiday as well I have to leave it on. Really bizarre. Does anyone know why this could happen ? 

 

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Not a heating engineer but maybe download the manual and check if you have a motorised valve inside the boiler? It could be that when the valve is in hot water position, it is watertight. It can probably stay that way just waiting for the stat to kick in and the pump to run. But when it is moved to heating only, it isn't watertight.  

 

 

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I had similar and it was the diverter valve on the heating. The seals go from the crud that accumulates. 

 

Ive done mine twice most recently after a plumber made a dogs arse of a job on stuff and I expect in filling and emptying the system multiple times stirred it all up.  

 

I bought a new cartridge from here:

 

http://www.buycombi.com/valve-check.html

 

excellent service and helpful. 

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Thanks - yes I'll have to get someone to look at it, but it is helpful to give them a clue. Sometimes they are clueless !!

 

 

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It seems to be temperature related as if you run it on a timer, then the pipes will be cooler than if it is constantly on.. The drip could be evaporating before it can get to the kitchen counter.. If the drip is on the right, then it is possible that the plastic flow switch or its seals have failed, on the left, then it could be a condensate issue.. Blocked con pipe, blocked or cracked trap or buggered sump and or sump seals, could even be a failed flue seal.. Either way it needs looking at and soon

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Check your condensate trap and drain pipe for a block.

 

With the boiler being 'on' regularly it won't be working that hard so not producing a huge amount of condensate in a short space of time. When it's on a timer, it will produce condensate quicker and perhaps this can't be drained away quick enough and it leak out.

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10 hours ago, Karl said:

It seems to be temperature related as if you run it on a timer, then the pipes will be cooler than if it is constantly on.. The drip could be evaporating before it can get to the kitchen counter.. If the drip is on the right, then it is possible that the plastic flow switch or its seals have failed, on the left, then it could be a condensate issue.. Blocked con pipe, blocked or cracked trap or buggered sump and or sump seals, could even be a failed flue seal.. Either way it needs looking at and soon

 

Thanks. Well it has been like it since at least November last year. That was when I went on holiday, and when I came back found a large empty Celebrations chocolate container on the bench almost full of water. It was total coincidence that was sitting in the right place under the boiler, otherwise it would have been all over the bench and the floor. Since then I've tried the timer a couple of times and always the same, the water. So it has been on 24/7 since then. So anyway I'll get it booked next week, and make sure it is off overnight and leaking before the engineer arrives. I doubt it saves much money, but I'd like to have it working on the timer satisfactorily, and of course be able to turn it off when I go on holiday. (that is the main reason)

 

It is a 15 year old Potterton Promax HE - not the best of boilers - but has had a new heat exchanger a few years back, both main circuit boards replaced, new burner and igniters or something. Anyway as long as it lasts another year before we sell the house I'll be happy, then it is a for the next owner to replace. It does run very well.

 

Edited by Tuvoc

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1 hour ago, Tuvoc said:

It is a 15 year old Potterton Promax HE - not the best of boilers - but has had a new heat exchanger a few years back, both main circuit boards replaced, new burner and igniters or something. 

 

 

At 15 years old to be fair its done well and is probably nearing the end of its life.  Ours was more or less rebuilt by the time it got to 15 years old and it went for a new one with a 10 year guarantee. 

 

Your boiler does sound like Triggers broom though. :lol:

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I imagine it has many years life left in it with all the parts replaced. And it is under contract with British gas so they will fix free. Assuming their engineers can actually see what the problem is. I've had a couple of good ones, and a few other useless ones. Unlike many other contracts, they will fix it regardless of age as long as part are available which they are, up to a max of £1,000 per repair I think it is.

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Watch with BG, they put their home care agreement prices up if you call them out and for big repairs like the heat exchanger.  I was paying over £400 a year.  No way, when after 3 years you have a new boiler.

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Yes it is ridiculous, you have to phone them and bring the price down. I probably won't renew again next year as we won't be in the house another full year after this agreement ends.

 

 

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On 08/04/2019 at 09:08, Karl said:

If the drip is on the right, then it is possible that the plastic flow switch or its seals have failed, on the left, then it could be a condensate issue.. Blocked con pipe, blocked or cracked trap or buggered sump and or sump seals, could even be a failed flue seal.. Either way it needs looking at and soon

 

It is on the left. British Gas are coming on Monday, I'll report back.

 

Can't see it being a blocked condensate pipe, it ran the central heating through winter, that is when it is working at its hardest and I would surely have had problems then if so.

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Been lucky, our Vaillant hasn't skipped a beat since install ten years ago. Had it serviced a couple of times for original warranty continuity but otherwise just check the inhibitor and empty the magnetic trap periodically - so far, so good. 

 

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OK, well even though the water was coming out on the left, the actual leak was the "flow switch" up on the top right which needs replacing. Parts ordered and he will be back tomorrow. Could be a whole mornings work he said. In which case an expensive job, but it is free as it is covered under contract.

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13 hours ago, Tuvoc said:

OK, well even though the water was coming out on the left, the actual leak was the "flow switch" up on the top right which needs replacing. Parts ordered and he will be back tomorrow. Could be a whole mornings work he said. In which case an expensive job, but it is free as it is covered under contract.

It can be a pain as the pipework would need draining down or freezing to allow the switch to be removed.. Last one I did, the water had found its way into the PCB and fried that too..

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Ouch - yes he said he will have to drain it down and need access to the loft as well. It still runs perfectly so the PCBs should be OK. Both of those have been replaced over the years.

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There shouldn't be any issues draining down the system to work on it.  I drained down mine at the weekend to remove a radiator.  Refilled and is running fine.  You just need to make sure you are methodical in bleeding out the air.

 

And unlike me, make sure you put some inhibitor in it.  I'll need to drain down again to refit said radiator so I'll put some cleaner in the system meantime.

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Well, he came today with the flow switch, which he thought would contain the circlip which holds it on, but it didn't. The old one was rusted and couldn't be re-used. So he needs to come back tomorrow to finish it off. He was here about 2 hours and there was occasional grunting and complaining so clearly it wasn't easy. When stuff has been there for 15 years I can understand it sometimes doesn't want to come off. 

 

I'm going to get a powerflush after this. Never been done in the 10 years we have been here, and unlikely to have been done at all since it was fitted. The system must be filthy inside. I want to give that boiler the best chance of surviving another 18 mths before we move. After that, the new owner is likely to rip out the existing kitchen and replace it anyway. Expensive job those powerflushes, cheapest I've found from a qualified person is 8 x radiators at £40 = £320 incl VAT. British gas of course want more than double that, rip-off merchants.

 

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