Hi Mark,
Sounds like a pretty antiquated set-up. The normal arrangement is -
Company tap - meter - consumer's tap - pressure reducer. The latter normally has a tapping to allow for a gauge (manometre) to be permanently installed on the downstream side. You might also need various adapters, hemp, plumbers paste, PTFE tape and some basic plumbing skill.
You need to get the pressure down to 3 bar.
Good luck!
I have had a look in the hole in the ground that houses the water meter and there is the on/off tap and a mechanical meter and nothing else except rusty pipe and snails.
The water leaks out when the tank is full, but not hot. I have considered an expansion vessel, but I think probably an inline pressure reducer should do the trick. I hope.
How much is it leaking? does it only pass water when it is hot? does it stop when you run the hot tap? if the answer is yes it is unlikley you have a faulty valve. I would suggest fitting an expansion vessel to the hot water pipework.
This may sound daft but we had the same problem a while back at first I thought it was the the valve then it was suggested it was the diaphragm that had been inverted. It turned out to be a problem with our electric meter in that a storm had blown the small fuse in it and blown the meter our problem resolved when edf replaced our meter
Mark you are pretty sure to have one and usually located near the meter. Sometimes these are hard plumbed and near impossible to remove without excavation. If that is true of yours, buy the same make pressure reducer and after switching off the incoming water and draining down just remove the top of the pressure reducer with the working parts and swap the parts over leaving the base attached.
It would work to a limited degree Mike, just whilst the taps are running, once switched off the pressure will build back up so not a whole lot of use. What is required is a test of the pressure with a gauge.
Thank you all for the responses. The increased water pressure suggestions appear to be the most likely problem. Two pressure release valves and three other sudden leaks is some coincidence!
So the thing for me to do is find, check and if necessary replace a faulty pressure reducer, or buy one and fit it inline somewhere. Sounds easy!
Don't think that works Peter. Pressure and flow-rate are not the same thing.
Mark - You should be able to try out the system at a lower water pressure by turning off your main supply tap & then opening it just a tiny amount - as little as you can get away with. The lower pressure can be verified by opening any tap where you should notice a reduced flow. Switch off the water heater as well, as these valves are there to relieve the extra pressure brought about when the heater comes on, so we don't want to confuse things should that happen.
If the relief valve still lets lots of water through when the incoming pressure is restricted, it could just be that the replacement valve is also defective. If it doesn't, at least you know that the problem probably lies with your water pressure. You may be able to temporarily fix the issue by keeping the main stopcock nearly shut, which at least should give you back a hot water supply. You would then need to install, or have installed, a pressure reducer (Réducteur de pression). They're about €40 at Leroy-Merlin, but most Brico shops & Plumbers Merchants should have them.
As for replacing the water heater itself, it can be done by a competent DIYer, though the unit can be difficult to handle on your own. I did mine (an upright 300 litre model) a couple of years ago when the contracted plumber didn't show up and my expertise is in software, not plumbing. The dead cumulus was over 16 years old in a very hard water area and had never been emptied of limescale, so its demise could probably have been expected. Yours might be at/near the end of its life as well, but that wouldn't normally cause the relief valve to permanently relieve. Just having a lot of limescale won't cause a pressure increase, apart from that occurring temporarily when the heater switches on & the water expands.
Good luck with it.
PS: Are you sure that the water is exiting via the relief valve itself and isn't a leak from the heater body that just appears to be coming from the relief valve?
So the pressure relief valve and other leaks, the incoming pressure is too high. The supplied pressure is usually reduced through a pressure reducer somewhere near the water meter. These do go wrong over time and so the high pressure is making it's way through the pressure reducer and not being reduced, could be a rusty spring or rotten diaphragm so needs replacing
Hi Mark
Glad I can now respond to your post! My husband has suggested that maybe your water pressure has risen, which could be causing the problem. Ours went from about 5bar to 7.5 - higher than is needed for fire protection sprinkler systems (husband's area of expertise)! So ask your water board if they have done/are doing any works that might have caused the pressure to shoot up. If it is the water pressure, then you need to put in a high-rated pressure valve. Try Screwfix!
Bonne chance
Julia
There seem to be four possibilities.
1./ You have been extremely unlucky and have had two faulty pressure release valves.
2./ You have left the valve in the open position - there is a lever that allows you to drain the tank.
3./ The thermostat has failed in the closed position. Easy to check by turning off the electricity.
4./ The input pressure is higher than the relief setting. Near where the cold water enters the house, there should be a pressure gauge and pressure reducing valve. This should be set to 3 Bar.
Does that help?