Pressure relief valve

2 Nov 2014
Reaction score
United Kingdom
Hi can anyone help please?
Last week I noticed that the pressure was low on my Worcester 28si boiler so I opened the pressure relief valve to increase the pressure. I thought I had closed it but today I noticed that there is a lot of water dripping from the outlet valve and the water pressure needle is in the red...above 3.0bars.

1. How do I know when the pressure relief valve is off? There is no visible off position. I can't remember which way I turn it for off.
2. How do I get the pressure down and stop the water dripping?
I don't want to call a plumber out if it is something that I can put right myself.
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The pressure releif valve does not increase the pressure, thats the filling loop.
You could let some water out of a radiator bleed valve, but if the filling loop is still on it wont happen.
Why would you open a Relief valve to increase the pressure?

The clue is in the name.

In view of your school boy error I suggest calling a professional before you do any more harm.
The PRV releases excess pressure. It is a safety feature. You should not use it to vent excess pressure when re-filling the system. If you overpressurise....find a drain cock and drain the system it down to nominal filling pressure cold. Make sure that all of the rads are bled lowest to highest. Top up/increase pressure at filling loop if required...AND MAKE SURE THAT WHEN YOU HAVE FINISHED TAKE THE FILLING LOOP OFF!! Put it on top of the boiler case for safe keeping.
If the PRV terminal doesnt re-seat it will continue to drip and you'll lose system pressure.
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OOOPS!!!! :eek: ditto Dan..... if you don't know what you are doing get sum1 in who does know!

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