Unvented Electric Water Heating Servicing Intervals.

burn:

Having watched the manufacturer's services engineer press the pressure relief valve button and then charge me £50 for each of the first two years, I now do it myself.


It's not difficult, but it is important to do it.

Does the PRV now leak or dribble ?


You need to be a bit careful using that method as it's very easy to get "crud" into the valve seat and often they will fail to re seat properly  - and then tend to leak forever after as the seat face gets damaged


Less likely on domestic water to be honest as that should be "clean"  - but not unknown


The last unvented system I had control over, I put in a bursting disk and discharge to drain just as a back up (because I wasn't going to pay for an annual service that is rarely undertaken correctly)


Regards


OMS

You can identify the flats in the building where it has been tested at some point, as there is chalk staining down the outside of the building under the little turn back pipes. I presume the clean walled ones are either new or untested.

A one time firing foil disc has a lot to recommend it, but is not standard fit, we seem to prefer a rusty spring and a rubber pad.

Sure thing Mike - bursting disks (and possibly flow fuses) aren't common in the "generalist" building services sector  - but in the sectors I tend to work in, it's never a bad thing to have a back up means of safety protection if things go horribly wrong - the big advantage of a bursting disk in conjunction with a spring seated PRV is they are incredibly unlikely to suffer a common mode failure. A bit like having 1250A HRC fuses up front in a switchboard equipped with ACB's - hopefully you never need them, but if you do, they will almost certainly work reliably even if they've been ignored for decades


Regards


OMS

AND. When I first did my G3 it was a life ticket. The scammers soon clocked that and now it's every 5 years. I mean, unventeds are hardly a cradle of white hot technological development requiring constant professional development are they?

Now, that reminds me . . .