Combi boiler overflow constantly dripping - help please

[OCdude]

I arrived home tonight, to find an angry letter from the people downstairs, telling me that my boiler is constantly dripping and it's apparently gone through their roof, caused damage etc etc

Now..... a while ago (4 months or so), my boiler went through a phase where it would make loud bangs when i put the hot water on - this eventually subsided so I just thought i was lucky!

The only strange thing I can see that my boiler does lately, is that it keeps the pressure at about 3.5 bar. If i bleed a radiator to reduce the pressure, it eventually goes back up to around 3/3.5 bar and sits there.

I'm a bit hesitant to get another plumber in ASAP because I think last time I was ripped off into buying a new heat exchanger (had problems where it was shutting off after having hot water running for a few mins). So i thought i'd see what anyone here thought first!

After Googling, the most common reply seems to be:

If the boiler is 5 years old or more then most likely it needs the expansion vessel re-charging or at the worst replacing and probably a new pressure relief valve fitting. The easy way to check this is to observe the pressure gauge, from cold it will read 1 to 1.5 bar when you turn the heating on if it rises to 3 bar in a very short time sa 5mins. then its the pressure vessel at fault. If its at 3 bar cold and leaking continuously then the filling link may be passing water, remove the linking pipe to test for this. If with the link removed it still leaks water then it has to be the water to water plated heat exchanger, to test for this turn the cold water "in" valve on the boiler off and release the pressure on your hot taps this should stop the leaking and eventually the pressure will fall on the boiler, that is assuming the discharge pipe has stopped leaking.

This is only a guide as to determine what might be wrong and possibly stop you from being riped off by a cowboy. If In the UK you will need to call in a Gas Safe Registered engineer to do the repairs, but it shouldn't cost the earth.Get an estimate before any parts are fitted.

That rings a vague bell, because i know that the linking pipe (which should be disconnected) has always been connected - and i'm a bit scared to disconnect it because i just have visions of flooding my flat like a total tard!

Any thoughts/advice would be gratefully received - i'm not sure how much time i have before the people below me start kicking my door down!

Thanks!

 

[teulk]

Sounds like a leaking pressure cap, we had the same problem. The temp would rise and then the water would be dumped out of the overflow pipe resulting in "low pressure" and the boiler not working until the system pressure was re-topped up. You may get around the problem (short term) by turning down the temperature setting for your heating on the boiler ( if you can). The radiators wont get as hot but it just might stop the water overflowing out of the overflow pipe.

 

[OCdude]

Wellll, i've bled a radiator, bringing the pressure down to about 1bar. However overnight it seems to have dropped to 1/4 bar, so i've had to top it up again.

Now it doesn't seem to be able to maintain a constant flow of hot water...... i just had a shower and it pretty much went: Warm-cooler-warm-cooler-warm-cooler........

I hate boilers ffs!