I have a Worcester Combi Boiler (can't remember exact model) and the pressure keeps falling. I have had a plumber out 3 times now and he has replaced the pump and PRV, everytime he has managed to 'fix' the problem but it gives up again after a couple of hours. He know thinks its either something to do with the compressor or a leak which means I'm going to have to rip up all my newly fitted flooring to find it - is this right?? Please help?!
Pressure Loss
- Thread starter sarajane
- Start date
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what compressor
na have another go
try expansion vessel
try expansion vessel
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are you losing water through the prv
what is the pressure on the guage (hot)
what is the pressure on the guage (hot)
if pressure is 1.2 hot it's too low cold
If a 'sealed system' is losing pressure, there are only two possibilities:
- leak outside the boiler
- leak inside the boiler
If the boiler is leaking internally, this could be:
- from the pressure relief valve, so water will be running out of the discharge pipe and down the wall outside. Engineer call needed to fix PRV AND to find out what made it run in the first place;
- leak between the two halves of the secondary heat exchanger (combi boilers only), so that water from the CH system and water heading for the hot water tap can mix (usually results in pressure RISING but leads to first symptom, above);
- leak from internal plumbing and / or components, leading to water dripping out of the bottom of the boiler. engineer job, usually.
A leak outside the boiler is often obvious! Damp carpet under a radiator valve or visible water somewhere else below pipes, rads, hot water cylinder, etc. Find and fix. If it's under a laminate floor - tough luck!
Either way, pressure on a sealed system WILL drop as the water leaks out (the difference between 1 and 0 Bar on the pressure gauge is usually only between 1 and 5 litres of water lost).
DO NOT under any circumstances leave the valve on the filling loop open to maintain pressure. The PRV WILL open, it's dangerous AND you will quickly wreck the whole system due to corrosion.
- leak outside the boiler
- leak inside the boiler
If the boiler is leaking internally, this could be:
- from the pressure relief valve, so water will be running out of the discharge pipe and down the wall outside. Engineer call needed to fix PRV AND to find out what made it run in the first place;
- leak between the two halves of the secondary heat exchanger (combi boilers only), so that water from the CH system and water heading for the hot water tap can mix (usually results in pressure RISING but leads to first symptom, above);
- leak from internal plumbing and / or components, leading to water dripping out of the bottom of the boiler. engineer job, usually.
A leak outside the boiler is often obvious! Damp carpet under a radiator valve or visible water somewhere else below pipes, rads, hot water cylinder, etc. Find and fix. If it's under a laminate floor - tough luck!
Either way, pressure on a sealed system WILL drop as the water leaks out (the difference between 1 and 0 Bar on the pressure gauge is usually only between 1 and 5 litres of water lost).
DO NOT under any circumstances leave the valve on the filling loop open to maintain pressure. The PRV WILL open, it's dangerous AND you will quickly wreck the whole system due to corrosion.
duplicate
duplicate
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