We have a 8 year old sealed CH system. Everything works fine, but occasionally it will 'spontaneously' drain itself.
It's been doing this for a while (ie a couple of years). What will happen is that it runs fine at 1-1.5 bar pressure, then the next morning it won't come on automatically. We take a look, and the pressure reading is at 0. Refill and it all works fine again. Sometimes it may work fine for ages, other times it may drain itself again just a few hours later.
It seems to be worse in cold weather. (not sure if that's relevant, but you never know - it occurred to me that there would be more expansion/contraction of the pipes in cold weather).
It only seems to happen when the heating is off. Eg, sometimes I've had to fill it when getting back from work at 6pm, I've checked at 11pm before going to bed, and everything's fine, but then in the morning it's down to 0 bar.
We've had plumbers in to look, but apart from stripping the whole pipe network out and reinstalling it they seem stumped unless we can find where the leak is. One plumber did find that the (external) PV had failed, so he put a new one in which 'seemed' to fix it for a bit, but the problem came back a few weeks later, and the PV still seems OK and there doesn't seem to be any water coming from the PRV (there was before he fixed the PV).
We've tried separating off different zones of the system for a day or two to see if we can isolate the problem, but that is inconclusive because it's so unpredictable. (If we run it with just the 'downstairs zone' and it doesn't leak, does that mean the downstairs zone is fine, or that it was just well behaved that day).
There are no obvious water stains anywhere even though loads of water must be coming out, which suggests the problem is on the ground floor (with the water leaking under the floor), but we also get lots of air in a couple of the upstairs radiators (which are on zones whose pipes don't go downstairs) suggesting the leak is near them.
I've looked under all the floorboards I can and have found nothing.
Any ideas of other things to try (other than to rip the whole thing out and start again
)
It's been doing this for a while (ie a couple of years). What will happen is that it runs fine at 1-1.5 bar pressure, then the next morning it won't come on automatically. We take a look, and the pressure reading is at 0. Refill and it all works fine again. Sometimes it may work fine for ages, other times it may drain itself again just a few hours later.
It seems to be worse in cold weather. (not sure if that's relevant, but you never know - it occurred to me that there would be more expansion/contraction of the pipes in cold weather).
It only seems to happen when the heating is off. Eg, sometimes I've had to fill it when getting back from work at 6pm, I've checked at 11pm before going to bed, and everything's fine, but then in the morning it's down to 0 bar.
We've had plumbers in to look, but apart from stripping the whole pipe network out and reinstalling it they seem stumped unless we can find where the leak is. One plumber did find that the (external) PV had failed, so he put a new one in which 'seemed' to fix it for a bit, but the problem came back a few weeks later, and the PV still seems OK and there doesn't seem to be any water coming from the PRV (there was before he fixed the PV).
We've tried separating off different zones of the system for a day or two to see if we can isolate the problem, but that is inconclusive because it's so unpredictable. (If we run it with just the 'downstairs zone' and it doesn't leak, does that mean the downstairs zone is fine, or that it was just well behaved that day).
There are no obvious water stains anywhere even though loads of water must be coming out, which suggests the problem is on the ground floor (with the water leaking under the floor), but we also get lots of air in a couple of the upstairs radiators (which are on zones whose pipes don't go downstairs) suggesting the leak is near them.
I've looked under all the floorboards I can and have found nothing.
Any ideas of other things to try (other than to rip the whole thing out and start again
)
