Vented heating system

[allenvb]

The Problem:
I drained down my heating system with no problem, and it was working fine, now I have refilled it and want to check it is all ok. It is now full but the downstairs rads won't heat up, I have a feeling there is air in the pump, but I have been told to bleed a pump you have to slacken the nut/screw in the centre of the pump, but there does not seem to be any air, there is an air vent cap quite close to it should i give this a go or would this be for something else?? Any suggestions would be great...oh and laymans terms would be a bonus..

Thanks

V

 

[ollski]

You need to bleed from that cap, then run for a few seconds and bleed again and again then bleed the rads, then the pump again and again until things quiten down a bit.

 

[ChrisR]

It might be an air lock in the pipes, try closing most of the upstairs rads.
Could also be that the pump is worn or going slow.

But you might well have a ton of sludge in your system. When drained down, this drops to the lower circuits and stops those rads working. No easy fix, it'll need power flushing.

 

[allenvb]

I have drained down the entire system today, made sure it was compleatly empty, turned off the pump, you name it I done it.

filled it back up, bleed the rads, bleed the pump, both by the air cap and released the the screw in the middle of the pump, I did this 2-3 times, turned the pump on.

Again the the upstairs heated up, but the downstairs stayed cold. I can't even 'pull' any hot water through the downstairs rads by bleeding.

BTW the pump now sounds like chopper trying to take off...someone please help.

PS Laymans terms again and please, please no glib, sarcastic answers I need help not the p**s ripped out of me!

Thanks

V

 

[Slugbabydotcom]

After following ChrisR's instructions above carefully try disconnecting a downstairs rad and connecting a hose to the valves. Flushing water out from each of these valves should drag out the airlock that seems to be causing your problem. Do it with all the downstairs rads if you have to. If you cannot get any water out you may have a blockage further back.
I see from your other posts that you are contemplating getting a new biasi combi fitted. This seems to me a bit like buying a new car because your caravan has a flat tyre. Biasi's are fine in my book but whatever you fit if you do go down that road, be sure to invest in a powerflush.