Combi Boiler - Pressure system loss - new valve 18 mont ago!

[Pilot853]

Hi
New to this type of forum so hope this reads okay

I have a Glowworm Xtrafast 120 Combi Boiler that was fitted in Nov 03
About Jul 06 I noticed a loss of pressure and water coming from the safety valve vent pipe. Had a new safety valve fitted and it seem okay until heating put on again as winter approached this year.

Details of problem:
When I fill the central heating system the pressure rises to 1.1 or 1.2 bar, the local water pressure. When heating is on pressure rises to about 1.5 bar. I then once again see water venting from the pipe outside. Pressure when the system is cold again seems to settle at 0.7 bar. Then when it heats up again max pressure is about 1.2 bar. After a couple of days system pressure drops to 0.6 bar, system shows a fault and I have to fill it up again.

This sounds like a new pressure relief valve required but surely it should not have gone wrong after only 18 months and why is it venting at such a low pressure? Is there someway I can change the pressure setting?

Hope someone can help and save me the cost of a new valve just before Xmas!
Thanks

 

[Agile]

Although rare it almost points to a faulty low reading pressure gauge.

I would be checking the mains water pressure to see if its really only 1.1 Bar.

Tony

 

[bengasman]

Could be that your prv has engaged at some point, only needs to be a tad. If there are particles in your system, that is all it need. Simple test. Find your drain cock. Rattle the nearest rad. Draw off a bucket of water. If you can see bits at the bottom, that’s your problem. it could be of course, but I find it a bit unlikely that you would have to defective prvs in a row. Even for a gw

 

[BOB D.O.L.E]

Sounds like a bit of crap on the seating of the prv try blowing off a few times gentley and this should cure the problem , been know to do it at least 8 times and you will need to repressurise.

 

[Pilot853]

Many thanks for your replies.
I found a slight leak on a rad valve and decided to drain the whole system to see if I could clear any particles in the prv as suggested.
Fixed the rad valve so no slight leak from there which could have caused some pressure drop but even better when I filled up and fired up the central heating there was no discharge from the overflow pipe. Must have ben a particle as suggested.

Once again many thanks