pressure relief valve

1 Mar 2010
Reaction score
United Kingdom
removed radiator then filled sytem up agin but the pressure has obviously got too high as dripping from overflow pipe, suspect pressure relief valve is faulty was wanting to know exactly how to replace it to stop the dripping from overflow when water is turned back on?
Sponsored Links
The PRV may have dirt on the valve seat which is allowing water to seep past, in which case it either needs cleaning or replacing. You have to drain off the water from boiler. I dismantled one that was dirty, but had to make a 'C' spanner to undo the spindle from the body of the valve.
If I'd had the spanner earlier I could have dismantled it without taking the valve from the boiler.
Of course there might be nothing wrong with the PRV and it's just doing what's supposed to do. Releasing the pressure when it reaches 3 bar.
Your pressure is supposed to rise by approx 1 bar, say 1.3 up to 2.3 for example. If it rises say 2 bar not only does it open the PRV, it also tells you the 'air' capacity in the expansion vessel has reduced and needs recharging.
It would also help if we knew the make/model of the boiler :?:

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Sponsored Links