wrote in message
...
Hi all,

I added a radiator to my sister's central heating system and fitted a
bigger radiator in her utility room. I drained the system before
doing the work then tried filling and bleeding afterwards. Bleeding
was a bit of a drama as air was trapped and I eventually ended up
letting the pump run for a little bit to get things moving.

Now the problem....

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Are you filling the system without running the pump and re-filling the
system after you have bled each radiator?

If you can, turn on the fill loop to a quarter of its full pressure, then go
to each radiator and bleed it until you get all the air out. This may take
a couple of minutes and a few bowls full of water, with a lot of spluttering
also.

Once you are sure the that radiator is getting full water pressure, move on
to the next rad' and so on. But you have to make sure you are drawing all
the air out of the system at each radiator in turn.

Do this with just the fill valve on. No pumps running. No boiler on.
Nothing. Turn the power off to the timer as well if you are not sure of the
settings on it, just in case it demands heating while you are doing the
bleed run.

Good luck with it.