Greenstar 40CDi boiler not firing up after re-pressurising

18 Dec 2012
Reaction score
United Kingdom
Right, the reason I wanted to re-pressurise the system was because the two radiators at the top of the house were not working properly (hot at the bottom but cold at the top), I was advised that this was due to low pressure and indeed the pressure gauge on the boiler was about 0.1-0.5.

So I re-repressurised the boiler which is now reading 1-1.5, but now none of the radiators heat up. I've bled all the radiators so that no air is trapped (when turning the key water spits out immediately, indicating no air is trapped). The weird thing is, the water still gets hot: when I turn on the hot tap, the boiler's indicator light turns on and the water gets hot. But, when I switch the thermostat to on (which normally fires up the boiler), the boiler does nothing, the pilot light doesn't come on and so the radiators are stone cold.

I really have no idea what to do now, if anyone can help, I'd really appreciate it.
Sponsored Links
So the boiler is working but not heating all rads...

Have you checked the pins on the TRV heads on the 'cold' radiators arent stuck down?

If these are ok turn the heating on...

Close TRVs on radiators that are getting hot, the heated water can now only go to the 'cold' radiators, unless there is a blockage.

Heat should make its way to all radiators, open TRVs to where they were originally.

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Sponsored Links