Glow Worm Micron 40FF - Downstairs Radiators not heating up?

[Ssthisto]

Gotcha, water's now maybe a little deeper than that - four or five inches - but there actually is water in there now.

Now that's done, what would the next step be? I've noticed that the Grundfos pump is making sucking-air noises and presume it'll need bleeding too (that's "use a screwdriver to turn the big chrome screw", right? Does the central heating need to be turned off when I do that?) so that it's not trying to pump air instead of water.

 

[dextrous]

Turn the screw until water trickles out. System can be on or off for this. Re-bleed your radiators. If all ok then it may be worth at least changing that ball valve.

Somehow I suspect that the system will need cleaning out, but that's a job for another day, as is changing that tank to a smaller one.

 

[picasso]

the chances are the cold feed to your central heating system is blocked, all you need to do now is find out where it is.

 

[Ssthisto]

Right, pump has been bled, radiators have been re-bled. I'll leave the radiators downstairs on overnight and see if they're warm in the morning; if that hasn't cracked it I'll have to try the balancing deal, although this could be difficult in one of the rooms because the radiator is not particularly accessible and *wants* to be left turned off completely.

 

[dextrous]

Should be warming up within an hour.

 

[Ssthisto]

It's also quite possible that the system does need to be cleaned out - as I said, this is the first time we've ever had any problems and therefore the first time we've ever really thought about the system as a whole, so it's probably got sludge I don't want to think about in there.

This is the problem with having grown up with a forced-air heating system - radiators are rather an alien concept to me!

 

[Ssthisto]

Update - things have gotten steadily worse since bleeding the radiators - so today I went out and got de-sludger (since the radiators that WERE heating up - now fewer than the radiators that don't - were warm at the top and sides, but not at the bottom or centre) and put that into the fill and expansion tank.

Now, we've noticed that the boiler's playing up; if I switch it off at the mains, turn the temperature dial on the lower left-hand corner right down, then switch it back on twenty minutes or so later, it'll fire up, showing a clear light in the "burner on" section, no light in "reset" - and then shuts itself off a few minutes later, burner light is off, reset light is off, switching the temperature dial does nothing, switching the power off only works if we leave it a while. That'd certainly explain the radiators not getting warm, if the central heating boiler's only running for a few moments at a time!

Any idea why it might be doing that?