rads stopped working ????????

[chiny15]

HELP

My cental heating system is heated by a back boiler behind my gas fire.
A tank in a bedroom with the pump and electic's
Header tank in the loft.

The other day the downstairs rads were cold while up stairs were ok
Bled the downstairs but still cold ( no air came out)
The following day 2 of the rads upstairs where just warm only the rad in the room where the tank and pump are was hot.
Checked the pump seamed ok but was very hot
Checked the header tank in loft, water was in but the water seamed warm.

any ideas

MOD

see 1a

 

[kevplumb]

Checked the pump seamed ok but was very hot

undo the screw in the middle and check the shaft is turning put a rag under it first

 

[Slugbabydotcom]

Another pump headed for the great pump graveyard in the sky. Could be a stuck diverter valve if you have one?

 

[chiny15]

taking the middle out of the pump do i have to drain the system first plus i have a three way port valve how do i check that this is working
thanks

 

[Slugbabydotcom]

Do it live. Cover any nearby electrics with plastic bag and a towel and have a towel or 2 handy. you will get anywhere between a tiny dribble and a 'scary piddle' while you get a screwdriver in and feel if the spindle is turning.
Personally I do that only if I'm not sure after I have used a big screwdriver as a listening stick on the pump. Just a buzz = siezed pump - Whooshy watery noise means its working.

To check Diverter valve:-

There is another way but this is the best

From cold turn on hot water only
The pipe leading from the DV [Think its port B]to the cylinder should get hot

Turn HW off [if possible] and central heating on - the pipe on the opposite side [A] should get hot.

Port marked AB on diverter is the hot water Flow from your boiler.

If you do need to replace the full diverter or just the head make sure you get more advice if you think you can do it yourself as I make loads of money out of clever @rses that have a go and get it wrong!

 

[andrew5235]

This is fortunate, I came on here this morning planning to post an almost identical problem, it sounds like my pump is seized as well then. I seem to have the same symptoms, cold radiators, buzzing pump.

However it rectifies it self when I turn the CH off for about 10-20 seconds and then back on, I suspected some kind of blockage as it is 20 years old. I put some sludge remover in at the weekend, do you think that this will sort out the pump as well or is it a gonner?

Thanks
Andrew

 

[Slugbabydotcom]

If its 20 years old its probably a goner or gonna be a goner soon. Sometimes a gentle tap with a hammer will get it working for a little longer as well but all you're doing is flogging a dead horse