Please help. At my wit's end, and yes, I've read and re-read all previous forum questions here and elsewhere! Worcester 28cdi combi natural gas boiler, approx. 6 years old. Has been losing pressure, ERRATICALLY, since we moved into the house (a 3 storey modern terrace) in April this year. A note the previous owners left in the Worcester manual would indicate the problem goes back further ("Open small grey knob under boiler to top up pressure as required.")
On the first of now 6 visits (I haven't paid a thing yet) the c/h engineers said, "PRV". I said it wasn't, as the external overflow showed no sign of wet at all. They then changed it. Twice. Still no sign of wet, and problem remained. They then said, "Heat exchanger". I said that the pressure only goes up on the dial by half a bar from the preset 1 bar. No problems reported from their stripping and checking the H/Ex. Next is the expansion vessel. Pressure still does not go up more than half a bar. Checked, pressure OK and put back. Problem remains. Pressure guage checked against engineer's master. OK. Next stab in the dark is "a leak on the C/H system" (there are no pipes hidden in walls or underground in concrete). No leaks found, but a tube of leak sealer added to the system for good measure. Problem still exists. Now what? The engineers are scratching their heads and licking their wounds at the moment, but the blasted pressure still drops, and I must emphasise this, it does so erratically. It can stay up at one bar for a week or more sometimes, and at other times it can drop to zero overnight. It's the same with C/H on or off, ie. with just HW ready for use.
Thoughts or, much more accurately, me grasping at straws-does the fact it's a three storey tall narrow house with the boiler on the top floor mean anything? Is it correct that the HW red light also comes on when the C/H is switched on, either manually or on the timer? (not the "in use" indicator, just the "on" one.)
Our mains water (checked by the engineer) is about 2.5 bar. If you calculate how many times I've topped it up and how much water has "disappeared", it just doesn't seem feasible that there's an undiscovered leak somewhere, especially as the pipework and rads are all so inspectable. The engineer suggested at one stage that having leaked out, all this water could be sitting betweeen floors waiting to enter when the plasterboard eventually gives way, but there is absolutely no sign or smell of damp anywhere, and we have left the house for two months during the summer. PLease help. Thank you.
On the first of now 6 visits (I haven't paid a thing yet) the c/h engineers said, "PRV". I said it wasn't, as the external overflow showed no sign of wet at all. They then changed it. Twice. Still no sign of wet, and problem remained. They then said, "Heat exchanger". I said that the pressure only goes up on the dial by half a bar from the preset 1 bar. No problems reported from their stripping and checking the H/Ex. Next is the expansion vessel. Pressure still does not go up more than half a bar. Checked, pressure OK and put back. Problem remains. Pressure guage checked against engineer's master. OK. Next stab in the dark is "a leak on the C/H system" (there are no pipes hidden in walls or underground in concrete). No leaks found, but a tube of leak sealer added to the system for good measure. Problem still exists. Now what? The engineers are scratching their heads and licking their wounds at the moment, but the blasted pressure still drops, and I must emphasise this, it does so erratically. It can stay up at one bar for a week or more sometimes, and at other times it can drop to zero overnight. It's the same with C/H on or off, ie. with just HW ready for use.
Thoughts or, much more accurately, me grasping at straws-does the fact it's a three storey tall narrow house with the boiler on the top floor mean anything? Is it correct that the HW red light also comes on when the C/H is switched on, either manually or on the timer? (not the "in use" indicator, just the "on" one.)
Our mains water (checked by the engineer) is about 2.5 bar. If you calculate how many times I've topped it up and how much water has "disappeared", it just doesn't seem feasible that there's an undiscovered leak somewhere, especially as the pipework and rads are all so inspectable. The engineer suggested at one stage that having leaked out, all this water could be sitting betweeen floors waiting to enter when the plasterboard eventually gives way, but there is absolutely no sign or smell of damp anywhere, and we have left the house for two months during the summer. PLease help. Thank you.
