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https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl DIY Forum >> Plumbing Questions >> baxi boiler https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1382972913 Message started by ade911 on Oct 28^th, 2013, 3:08pm

Title: baxi boiler
Post by ade911 on Oct 28^th, 2013, 3:08pm

on an baxi 105 e boiler I need to replace the pressure relief valve, as its leaking outside. Anyone know if I have to drain the system first? and tips will be great thanks
Ade

Title: Re: baxi boiler
Post by Lectrician on Oct 28^th, 2013, 3:30pm

You would need to drain down at least the boiler - I am not familiar with the Baxi, but assume it would have an isolation valve on the flow and return pipework, and a drain-cock somewhere on the boiler. You would then be able to change the PRV valve.

BUT...

Is this PRV valve 'leaking' because it has gone duff (some crap stuck to the valves seat, causing it to let by), or is it doing it's job? Is the pressure in the system normal, or gone to high? If it's gone too high, it could be due to a failed expansion vessel, or because mains water pressure it's finding it's way into the system via a dodgy filling loop, or a failed heat exchanger (combi DHW).

Scruff will help later...

Title: Re: baxi boiler
Post by thescruff on Oct 28^th, 2013, 4:14pm

Not a lot to say that hasn't been said.

Set the pressure at 1.4bar then post how high it goes when you turn the heating on.

As Lec posted, you likely have an expansion vessel problem.

No point changing the PRV until you know why it failed as the new one will do the same.