Downstairs radiators not getting hot

[NickCurtis62]

My setup.
1. Radiators downstairs & upstairs
2. Hot water tank, header tank etc in loft
3. Gas boiler - old type, not an 'on-demand' type

My problem.
Upstairs getting hot but downstairs not except one that only get's slightly warm at the top, and i think this is only happening due to hot water being pulled by gravity from the radiator directly above it upstairs.

What have i tried?
1. Powered up the boiler and turned up the temp for both heating and water.
2. Bled all radiators - trying with and without the boiler on. Not much air escaping when i tried this. Pretty much water coming out from the get go.
3. Water pump up in the loft appears to be running but does feel very hot. This is the pump for the radiators is it?
4. All radiator valves are open.

Can't think of anything else obvious to check.
Any idea's would be appreciated.

 

[Jadele]

shut off the upstairs rads and see if the downstairs get hot

 

[NickCurtis62]

Thanks for the tip - tried it but no change

 

[75pete]

Try this; remove bleed screw of the pump. Now with the pump running, check that the pumps impeller is spinning.
Expect some water once you remove this large bleed screw, so have a cup etc to collect the small amount of water.
Also see FAQs 14 & 20 before starting the above.

 

[gigz]

Try this; remove bleed screw of the pump. Now with the pump running, check that the pumps impeller is spinning.
Expect some water once you remove this large bleed screw, so have a cup etc to collect the small amount of water.
Also see FAQs 14 & 20 before starting the above.

What he said. Or is your heating on two different zones ? Pics would be helpful.

 

[NickCurtis62]

Thanks for your replies people.
Going home now to check out this pump. Have a replacement one just in-case!

Do i need the pump under power when i remove the bleed screw? I'm assuming under power
but thought it best to check. If the pump is spinning/pumping what next?

Any pointers on changing the pump? What should be turned off other than power to the pump?

FAQ's 14 & 20? Tried looking at the top of this Forum but the FAQ's there don't have 14 & 20.
What are they in brief?

 

[Stadan20]

My money is the pump

 

[NickCurtis62]

Well, tried an identical pump and the fault is the same as at the start.
Set the pump to No.3 and shut down all upstairs rads but no difference,
even after 30 mins running on No.3
Open up upstairs rads and warm within minutes.
Anymore idea's out there?

 

[Davidl66]

Isolate one of the radiators downstairs that don't work. On both sides remove the radiators and slightly open the valve to see water flow
Ifrom water is blackish or brown I'd advise you to get a good power flush.