Cold downstairs rads after changing bathroom rad

[AndyKnight]

As our bathroom radiator was starting to show rust on the bottom edge I decided to to replace it with a nice towel radiator. Due to the system drain valve being in a really bad place to get access to I drained the system by just loosening the connector pipe to a radiator in the kitchen.

This did the job nicely however whilst the system was empty I took the oppertunity to change the valve on the kitchen radiator for one with a drain off on it.

Once empty I took the old bathroom radiator off and installed the new towel radiator successfully. I turned back on the water and let the system re-fill then bled each radiator starting with the bottom ones and then moving to the upstairs.

I started the central heating back up and the new towel radiator together with the two bedroom radiators all heated up with no problem.

The problems started to show as neither of the two downstairs radiators would heat up. I went round all the raditators again to bleed them however nothing happened.

I turned off all the valves to the radiators that were hot in an attempt to force the two downstairs ones into action. At thi spoint I went out for several hours and came back to find the downstairs radiators were quite warm.

I thought the problem could be sludge related so I drained the system again and added some sentinal x400 sludge remover before re-filling and re-bleeding everything.

After an hour the downstairs radiators are cold again ( I opened up the valves on all radiators after addinbg the x400). I have tried to close the upstairs valves again in an attempt to force the radiators into action again downstairs however this has not worked.

The boiler is a baxi solo 2 40 pf and the CH pump was replaced 4 months ago by British Gas.

Does anybody have any ideas?

Thanks

Andy.

 

[Agile]

This did the job nicely however whilst the system was empty I took the oppertunity to change the valve on the kitchen radiator for one with a drain off on it.

Thanks

Andy.

Some of those drain off valves only drain off that rad !

You must leave the X400 for 4-5 weeks before draining it off.

How black was the water?

It sounds as if you may have air in the pump. See the FAQ on this site for how to bleed this.

If that fails to solve it then do the "bucket test" on the downstairs rads as described in the FAQ.

To help the X400 circulate in the DS rads you should turn off the upstairs rads as much as possible.

Tony

 

[AndyKnight]

The drain off I fitted is sufficient to drain the entire system as I have used it twice to do thi snow trying to solve my problem.

The water drained off the very first time was quite clear until it got to the very end.

The second time I drained the system it was quite alot blacker with a few tiney bits in it.

 

[AndyKnight]

also if the pump needed bleeding would that not mean that none of the radiators would be warming up? Ther upstairs radiators heat up within about 3 minutes.

 

[AndyKnight]

I've bled the pump now and only water came out. Something which may or may not be related is that as I was pressing against the pump to turn the bleed valve in the middle of the pump the bottom of the pump that joins onto the CH pump started to leak. As far as I can tell it's the fixing that joins the pump to the pipe which is leaking but it only seems to do it when I push against the pump.

I guess when British Gas replaced the pump they didn't do the connection up tight enough or something?

Anyway I guess I'll have to get them back out to tighten the connection up as there is not enough room for me to get any type of grips, spanner or wrench on it to tighten it up.

Do you think this could also be causing my downstairs rads to not heat up. Maybe it is sucking in air although no radiator I open the bleed nut on lets out any air.

Thanks

Andy