New radiators, new pump but still not warm!

Chrispie

Hi again, I have just tried the magnet test on the pipes but it did not stick to either side. Should I try the magnet in any other area?

keystone

You obviously have a circulation problem.

Is the pump the right way round? No its not as silly a question as it sounds. Even if it is the right way round you could be getting reverse circulation through your rads if you have a blockage.

Have you got an open vented system like this:


Look at the image. To the left of the pump are two vertical pipes coloured grey. The first is the vent up to the F&E tank. The second is the feedpipe. Where the feedpipe joins the primary circuit is the usual suspect for a magnetite blockage particularly if you have an air separator like this one:



because they can get full of crud on an older system.

Lets confirm that the system configuration per the image is correct first (if not please describe it) then take it from there.

Cheers

Chrispie

Thanks Keystone, your diagram is exactly how our system looks. It's definitely open-vented. Not sure yet if the air separator like the one in your picture, if we have is there a way to clear the crud from the system?
Also not sure whether it's relevant or not but I replied to a previous post that we don't have pipes dropped from the ceiling to the downstairs radiators but in fact we do.

keystone

If you have got a magnetite blockage no flush of any shape, size or description will shift it. The affected pipework has to be cut out and replaced. No I don't think its relevant tbh.

Cheers

jcb208

If the system was getting hot before replacing the rads you may have an airlock in the pipework somewhere which can be hard to get out.Putting mains presure water through a drain off c ock can sometimes work if you have an open vented system

Chrispie

Will the magnet test on that piece of pipework confirm if it is a magnetite blockage?
Thanks so much for your time and suggestions, we really appreciate it

Chrispie

Also thanks to you jcb208. My OH will try this at the weekend, is this also called a reverse flush?

keystone

Chrispie wrote: »

Will the magnet test on that piece of pipework confirm if it is a magnetite blockage?

No always unfortunately.

...is this also called a reverse flush?

No a reverse fill. Make sure that the hose is very very tightly attached to the spigot on the drain !!!! wuth a jubilee clip. The mains pressure can easily just chuck it off and then you get very wet.

Cheers

Chrispie

Hi Keystone, we do not have an air separator on the system Is there anything we can do to clear or remove the blockage?

gamston

do you have any air vents on the system, normally they are black about the size of a fist with a little plastic screw cap on top,
just slightly unscrew the cap and it releases the air that is trapped
when i refill my system it takes weeks to get all the air out, but i have a 14 rad system that has had bits added here and there