Glow Worm Xtrafast 120 Combi Boiler, water loss PRV

15 Dec 2008
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United Kingdom
Glow Worm Xtrafast 3 - 4yrs old.
Initially, water loss through PRV, fitted new PRV.
Still same problem, checked pressure on boiler expansion
vessel, vessel full of water! thought i'd found problem.
Fitted new exp vessel in line. Then customer told me that
pressure rises from set position of 1.2bar to 2.5 - 3.0bar but still loses water
through the new PRV.
My thought now is, there is something wrong with the
plate heat exchanger.
Would be very grateful for other thoughts and opinions
Cheers Philgreg
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check if the new expansion vessel is pressurised.sometimes the new ones also lose air pressure. :D
Hi Lunat
Checking new expansion vessel pressure was the first thing I did
after fitting, it was pressurised correctly
Thanks for the thought though, any other ideas?
So why don't you just get them to leave the heating off for a period of time, thus proving plate he ??
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Why try a new filling loop?
If it is a normal braided hose, just take it off when finished filling.
Hi Philgreg

I have exactly the same boiler with exactly the same fault symtoms you describe above. Did you ever get to the bottom of your problem? btw i have also replaced the prv....still leaking.

Dear All

I finally got to he bottom of the water venting from the PRV. The problem was a blockage in the braided hose bewteen the expansion vessel and the other end of the hose. I removed it and cleared the blockage, then refitted. The pressure was now staying at a nice steady 1.0 bar. Only problem was , the PRV was still leaking water, but this was due to it being crusted up with crud from months of venting off. Took off the PRV gave it a good soaking in limescale cleaner and refitted. All sorted ater that, it's been a month since my DIY repair and so far it's been as good as gold.

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