Fitting a new Grant external boiler: why the note re filling and whats the proper way of filling it

Calahonda52

Thanks

Wearb

Probably because they are often left in the circuit to conceal minor leaks or even expansion vessels that aren't working.

Calahonda52

https://www.boards.ie/discussion/comment/119803269#Comment_119803269

Okay so I can use the loop to fill but not leave it open all the time, as it was before the boiler casing cracked in the old one.

Ps hope all is well with you :)

Keep well.

Wearb

Ideally it should also be disconnected at outlet side, but give Grant a call. They might be happy to just have it turned off.

Yes. Fine thanks

John.G

A bit strange that bit about invalidating the warranty when using the auto fill, even though they are hateful items IMO in that if left open they mask any slight leagages which in turn can rot away the rads and presumably the boiler as well, a auto fill is only a drop tight PRV thats left open permanently, I think the boiler PRV (safety valve) is set to 2.5bar on these so require proper precharge and filling pressures especially if they have a internal E.vessel which tend to be smaller than external ones.

You might post the volume of the one installed and whether internal or exernal and also how many rads & single or doubles.

jimf

i would imagine grant dont want it because of the 5 year warranty on the boiler shell

boiler leaks nobody checks why

and then you see a few rads around the back of the garage and ask a few questions

John.G

Is the 2.5bar PRV setting common to more boilers now?

Tom44

A permanently connected automatic filling valve is against the water bylaws, You must use a disconnectable flexible filling hose that's left disconnected afterwards. You can still incorporate a pressure sensing filling valve, but it won't be automatic as it shouldn't have a permanent supply of water.

It's to avoid the reasons listed previously and also to avoid possibility of contaminated heating water been syphoned back into clean water mains supply if mains are shut down for repairs.