I have a British Gas contract and they are being incredibly helpful, have replaced a couple of obvious parts (pressure relief valve, pressure switch (or whatever it's called)) but the boiler is still losing pressure incredibly quickly (ie drops from 1 bar to 1/2 bar after say 6 hours of central heating being on) and therefore a lot of water must be being lost very quickly somewhere. There are no obvious signs of water loss, no underground pipes, no hint of leakage on the downstairs ceilings from upstairs pipework even when the heating is only on upstairs (where the boiler is, and a diverter allowing water into the downstairs circuit is shut off) and therefore in theory the water loss must be upstairs somewhere. Could it somehow still sneak through the pressure relief valve? I know it's a ridiculous request but anyone any suggestions? B Gas are saying after 4 visits to call them in the new year as by then something must have started to show but there is very little hidden pipework...
Ideal Response 120 loses pressure, therefore water, but how?
- Thread starter simonski1
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have they checked the expansion vessel ?? Tie a bag over the relief pipe outside. If there is any leakage there it will collect in the bag. Also observe the pressure gauge from cold to hot, does it change very much?
First and foremost thanks for offering help. They've checked the expansion vessel and are happy that that's ok. I thought about the bag idea and will indeed try that, albeit I've looked out at the relief pipe many times and there's never been any sign of leakage - could it have a sudden sneaky blast, but which has happened many times? The pressure gauge certainly changes but not (in my mind) anything too radical - if it's 3/4 bar cold it'll go up to 1 1/2 bars when hot, maybe hit 2 bars if it starts at 1 bar cold.
Going from 1 bar to 2 bar is a little more than normal. That would indicate a lack of expansion, either the vessel is not charged properly, is faulty, or the pipe going to it is blocked. If it was the cause of your loss then yes it would release the pressure in a short burst. I would definately try the bag idea for starters.
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As micky correctly says its highly likely to be a prob with the pressure vessel. ive had to change numerous on the old 120 response. regarding the sudden burst from the PRV, yes that too is a possibility which would according to your description would happen if you had a faulty pressure vessel, however, you would undoubtedly be alarmed when it blew off, they can make a right racket when they go!!!
ps. dont assume that coz someone from BG said its ok thats that law!! their engineers arent all brilliant.
For me it would be simply repressurise pressure vessel and if problem persists replace pressure vessel. Its quite an easy job to replace them on the 120 response
ps. dont assume that coz someone from BG said its ok thats that law!! their engineers arent all brilliant.
For me it would be simply repressurise pressure vessel and if problem persists replace pressure vessel. Its quite an easy job to replace them on the 120 response
Again, thanks for all of these useful comments. I'll try the bag thing first - it's seems the simplest and most obvious. If there was a noise coming from the boiler from a "blow-off" it is possible we wouldn't hear it as the boiler's in the loft and we tend to be on the ground floor. Presumeably the bag idea would actually indicate either a faulty PRV or pressure vessel, and more importantly if the bag remains empty then it isn't the boiler at all and therefore something far more worrying and seemingly (currently) difficult to find...
We had a similar problem with our Response 100 and had to top up the system a couple of times a day. Our engineer replaced a couple of smaller parts first and pumped the system up three times, but all the way along had said the expansion vessel had gone and it had a minute air leak. We didn't have a blow out, but water was slowly been discharged outside when the boiler was in use. If water is collected in the bag then there's a resonable chance it could be the same problem. Our pressure gauge was reading up to 2.5 when the heating was on, but within 3 weeks it was 3.2 and the pipes were creaking in the house. If you start getting readings like 2.7 I'd insist British Gas come back immediately to review things, as it may take them a few days to get a new expansion vessel.
Madmog, the pressure never gets that high unless of course I top it up too much when the system's cold. I do know the basics about plumbing having worked as a plumber's mate for 8 months but can you confirm for me, if it IS the PRV or the expansion vessel then the plastic bag will start to fill, and if it's NOT the PRV or expansion vessel then the bag wont fill and it has to be a leak elsewhere on the system? There is no other "official" escape route from the system apart from the drain tap is there? I've put a sheet of newspaper underneath the boiler to spot any leak from within there. One of the B Gas guys put some leak sealer into the system in case there were maybe a few small leaks.
And by the way, I'm totally aware that B Gas will have both good and bad engineers but certainly the couple who've been here have talked total and utter logic, and as such so far so good, but I'm still losing pressure!
And by the way, I'm totally aware that B Gas will have both good and bad engineers but certainly the couple who've been here have talked total and utter logic, and as such so far so good, but I'm still losing pressure!
Simonski this is a very very common problem on the Resposes, particularly the 120. You may well find that if you don't use the boiler it loses a lot less pressure. This is because the water leaks through the main heat exchanger when it's in use, and evaporates and goes out of the flue.
If you leave it , it'll get worse, and one day the boiler won't light because it's full of water in the burner chamber.
If that's so, it's fairly easy to diagnose by removing the fan and an electrode, but I don't recommend you do it yourself. The water leaks and stains so it's easy to see.
The heat exchangers were always very expensive and not easy to change. Eventually Ideal ran out and the boiler was declared unrepairable, but then another company started making the hexs , with a delay of 3 weeks and a cost of a mere £180, iirc, so Responses were repairable again. The situation is "fluid" so I suggest you call Ideal.
The pressure vessels do leak too, but you usually see it, dribbling down the side of the grey aluminium gas valve, lower right.
The problem with replacing the boiler, is that there's nothing as small.
If you leave it , it'll get worse, and one day the boiler won't light because it's full of water in the burner chamber.
If that's so, it's fairly easy to diagnose by removing the fan and an electrode, but I don't recommend you do it yourself. The water leaks and stains so it's easy to see.
The heat exchangers were always very expensive and not easy to change. Eventually Ideal ran out and the boiler was declared unrepairable, but then another company started making the hexs , with a delay of 3 weeks and a cost of a mere £180, iirc, so Responses were repairable again. The situation is "fluid" so I suggest you call Ideal.
The pressure vessels do leak too, but you usually see it, dribbling down the side of the grey aluminium gas valve, lower right.
The problem with replacing the boiler, is that there's nothing as small.
ChrisR, thanks for that and it sounds a very interesting possibility if there is no water collected in my bag - there are no obvious signs of leakage on the radiators or pipework. But, could the pressure really reduce from 1 bar to 1/2 bar in, say, 6 hours through evaporation through the flue?
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