British Gas CDI boiler losing pressure - Worcester

[baldie10]

Hi all, A few weeks ago I noticed that all of the upstairs radiators had stopped working...all stone cold, and that the radiator in the lounge was making strange gurgling sounds...so I thought it would be a good idea to bleed all of the radiators...did this and loads of air seemed to come out of pretty much all of the radiators, made myself a cup of tea happy with my work and then suddenly a loud screeching noise came from the boiler and it overheated as it had 0 pressure. I then topped it up and over the last couple of weeks have bled the radiators, topped it up etc etc. Anyway, now all of the radiators are completely full and work, ie if you try to bleed them only water comes out. However, the pressure on the boiler keeps decreasing at an alarming rate, i.e. about 2 bars overnight and I keep having to top it up. I've checked the valve outside and it seems dry? There are no obvious signs of a leak and if I had a leak somewhere wouldn't one or some of the radiators have drained a little?
Thanks

 

[swbjackson]

The rads don't necessarily empty themselves when you've got a leak. If the pressure is dropping that much you need to find that leak. As well as promoting corrosion to the heating system it could well be doing structural damage to your property.

Mike

 

[baldie10]

Thanks Mike, could it not just be a problem with the boiler itself rather than a leak though? Seems very coincidental that it started as soon as the rads were bled?

 

[swbjackson]

The only way it can lose pressure is if the water goes somewhere, either from a leak in the pipework or via a problem in the boiler. You say you've checked the outlet from the PRV and it's dry so I assume it's on the pipework.

It can be proved one way or the other by shutting the boiler off and closing the isolation valves to the heating system. If the pressure loss is through the boiler the gauge will drop, if it's through the pipework the pressure won't drop until you open the valves again.

Mike

 

[bengasman]

what do you mean by:

seems

dry?
it leaks, or it does not