WB 24i Junior losing pressure...

[danmanchester]

Morning all,

I've got a WB 24I Junior that seems to be losing around 0.5bar of pressure per week. I've checked the system and can see no signs of visible leaks so I assume I need to replace perhaps a PRV in the boiler or something?

All advice welcome...

 

[vicvapour]

A more primitive (and cheaper) test if you want to try this beofre you splash out on a PRV is to tie tissue just underneath both valves on all radiators, its worth eliminating this as a problem first as the valves may be weeping.

Next if you suspect the PRV is letting by (dumping water form your system) through the blow off pipe, can you see where the pipe discharges too, keep and eye on it, to see whether the water is actaully coming from this pipe peridically, if it isn't at all, the leak could be in the pipe work (underfloorboards, etc).

If you still can't find the leak at this point I would be looking towards the boiler itself being checked.

Hope this helps.

 

[danmanchester]

A more primitive (and cheaper) test if you want to try this beofre you splash out on a PRV is to tie tissue just underneath both valves on all radiators, its worth eliminating this as a problem first as the valves may be weeping.

Next if you suspect the PRV is letting by (dumping water form your system) through the blow off pipe, can you see where the pipe discharges too, keep and eye on it, to see whether the water is actaully coming from this pipe peridically, if it isn't at all, the leak could be in the pipe work (underfloorboards, etc).

If you still can't find the leak at this point I would be looking towards the boiler itself being checked.

Hope this helps.

Thanks for your reply. I'll run round tomorrow and attach tissue paper to the rads to see if I can find it. Perhaps I'll put something under the PRV to catch the output (assuming there is any...).

If its not leaking nor outputting thru the PRV what else could it be?

 

[vicvapour]

Just as ive said mate under the floorboards, if its not the valves, rads, or PRV.

 

[Dopeydaz]

I'd check the expansion vessel, over the top of the boiler there is a round red expansion vessel. On it there is a valve that looks like a car tyre valve, take the dust cap off and try and let some air out. Just a little bit. It should be air if there is water in it you need a new expansion vessel.

If you want to check the blow off valve I sometimes tape a freezer bag over the end of it and check it after a couple of days. it lets you see if any water has gone in to the bag but obviously if the prv is "activated" it isn't strong enough to stop the water getting out.