Unvented System, Caleffi Pressure Relief Valve Issue?

[tom99]

Hi,

I have an unvented system and in the cupboard where the hot water cylinder is there is a mains pressure cold water feed, this goes through a 3bar cold water control valve / 6bar PRV combo before going into the hot water cylinder (see pic 1 & 2).







The relief side of the PRV is dripping (almost a steady stream) into the tun dish at the back bottom corner.

I had this same issue in August and replaced the PRV for a new one and it solved the issue. However, it is back.

The PRV shouldn't fail in 4 months should it?

Could there be another underlying problem in that the PRV is actually working correctly and that it is relieving high pressure?

The cold water control valve is a 3 bar unit and as such should restrict the downstream pressure to 3 bar correct? Do these control valves ever have reliability issues?

Mains water pressure is approx 5 bar.

Look forward to some advice 🙂

T.

 

[chris watkins]

Hi Tom
Do you possess a Part G ticket sometimes call un-vented ticket ?

I know you don't because if you did you would not be asking, unfortunately to work on these system you must have had the training & assessment to do the work safely.

So we regret that we can not provide information that would encourage you to break the Law & put you & yours in danger.

You need to call a plumber & please ask to see their current card for the Part G.

 

[johnf]

Are you qualified to work on unvented cylinders?

 

[Best]

It is illegal to work on unvented units without qualification, so you need to get a G3 qualified person to fix the unit. It is supposed to be serviced once every year for safety and to keep the long warranty and also to keep the unit working fully

 

[ShaunCorbs]

easy fix but unless your qualified cant give advise sorry

 

[Dotty]

So I think we'll end it there....