Isar pressure gauge shows 1 bar constantly (hot or cold). Heating on and as it gets warm PRV lets water out, drips at first building up to a small trickle. The gauge continues to show 1 bar. Filling link disconnected. I know what I suspect but before I put ideas in any ones head I'll let you all loose on this strange phenomenon
Hmm is the guage reading correctly. i had the same fault on a ferrolli optima took me a few goes then to find the guage was knackered .Or possibly just a faulty prv
I am pretty sure the domestic ht xch is knackered but the gauge only showing 1 !! it must also be goosed possible stuck on 1 , I did drain a bit of water out to check if it dropped a bit , which it did, but filling the system after wouldnt take it higher than 1 . I hate isars, cant even get my fingers to the PRV , god knows how you change it, as for the domestic heat exch . This'll teach them to get warmfront in.
If the vessall was flat the system would heat up , blow off through the prv ,cool down and have a shortage of water, this is litterally running water out the prv, so it has to be mains filling through the domestic ht ex as it gets warm. What i cant get is the gauge showing 1 and the prv opening , it has to be a false reading or the prv is opening at 1
that wouldnt allow the prv to open .somethings taking the pressure up in the boiler / vessel flat or cracked wtr to wtr exchanger
This customer had a perfectly good 28cdi that Id fitted and then she had warmfront fit this for her behind my back and now Ive got involved in repairing it. She going to pay . ha ha
Two things first you said in first post it gets worse when heating is on so Bill is correct your clearly got a problem due to expansion one way or another. Also PRV's a cheap i only takes them to open a few times under system pressure and the spring loses its like and the either never seat properly or pass at a lower pressure than the intended 3Bar. As for calorifier, isolate cold feed to boiler and run heating if problem still occurs you can rule out calorifier passing as theres not cold feed into it now.
Its not the exp vessel cause the damn thing runs like a tap and yes if you turn the cold off to the boiler it does stop eventually. The mystery was the 1 bar thing
Thnk your probably right then mate faulty gauge. If its any help think the PRV's on the isar are quite easy to change there push fit O ring type secured by a clip. Back right of boiler take bottom panel off should be able to get to it. Totally agree though piece of **** boiler, strange thing is sure Warmfront used to fit Vailiant not so long ago, don't know why the swapped not like ideal are cheap to buy?
you could try connecting a separate gauge on the heating side of the filling loop,just to confirm the accuracy of the internal gauge.