Dripping pressure relief valve on a sealed system

[darkart]

I'm having problems with my heating system with the pressure relief valve constantly dripping cold water.
I have exchanged the pressure relief valve, changed the pressure reducing valve (now fitted with guage) and alos changed the expansion vessel, but still it drips.

It is also fitted wit a cylinder tank, but the pressure valve on that cant be faulty as hot water would drip out.

Any more ideas on what could be the cause?

 

[dilalio]

More details of your whole system, in intelligible text.

Unvented cylinder? G3 qualifications?

 

[darkart]

I'm having problems with my heating system with the pressure relief valve constantly dripping cold water.
I have exchanged the pressure relief valve, changed the pressure reducing valve (now fitted with guage) and alos changed the expansion vessel, but still it drips.

Any more ideas on what could be the cause?

Forgot to mention, it has a cylinder tank

 

[darkart]

got em, would rather have some advice thanks

 

[dilalio]

And a cylinder tank is?...

 

[Iamchamps]

After my new boiler was installed and the CH was turned into a sealed system over the following weeks I kept losing pressure. The plumber advised to look for leaks etc but nothing could be found. With the great advise on here a suggestion was made to put a small bag round the PRV to see if that is leaking over a few days it slowly filled up and to my joy the leak had been found. The plumber came back and advised sometimes small amounts of crap gets in where the release button is and to "Blast it" to solve it. This was him letting water out through the valve in small burst and then refilling. After about 6 or 7 times he said that should be fine now. The system has since never lost pressure again.

While the above may not help your situation this is what fixed mine. Thanks and good luck.

 

[dilalio]

He says he's already changed the PRV.

 

[Madrab]

It is also fitted wit a cylinder tank, but the pressure valve on that cant be faulty as hot water would drip out.

If it's an un-vented HW cylinder then you could have 3 pressure relief valves. If the un-vented EV or bubble is no longer absorbing the HW expansion, it can then pass cold water through the PRV on the inlet controlset/multibloc.

If it was warm then it would be the Temp&PRV passing.