Advice on topping up boiler

[Jay091276]

Could someone tell me step by step how to top up a boiler as I don't understand what I'm doing wrong. The filler loop is already attached to the mains cold pipe, it just needs attaching to the central heating return pipe. When I take the nut off the return pipe, lots of water starts to drip out and doesn't slow down. I have tried attaching the filler loop anyway and then turn the valve to try and fill it but cold water starts spraying out of the filler loop, like there's loads of little holes in it, although there can't be as it was fine last time. It's like the water coming out of the return pipe is stopping the other water from going through and topping up.

what am I doing wrong or is there something wrong with the boiler? I want to top it up as the pressure gauge is between 0.5 and 0 although the heating and hot water seem to be working?!

 

[Simon F]

Hello Jay, welcome to the forum.
if you could post a photo of the loop and fittings it would help.
the ch return is probably fitted with the double check valve that might have developed a fault,
but without seeing what you describe or having more details it is a bit difficult.

 

[Jay091276]

Hi thanks for quick response. It is a ProTherm 100e boiler. Have attached 3 photos, hope they're clear enough!

 

[Mike Jackson]

The double check valve has failed. This sort of loop does not comply with the water regulations anyway so you need to swap it for a compliant one. This may require a partial drain down of the heating system.