downstairs rads cold, replaced pump still no CH

[stuartguffy]

Hi

I have 18 year house with Netaheat boiler located downstairs, at present I my rads upstairs get hot after about 1/2 hour and downstairs get no heat at all. I have checked they are all turned on. My mate came round late last night and changed the pump but there is no change.

The system is microbore to all rads, he says it could be the cold feed blocked as is an air seperator but thought was a bit strange that upstairs still get hot eventually. The other idea is that there is a manifold somewhere that could be blocked?? but we could not see one.

What we are going to do is cut out and remake the air seperaor and take off all the rads and flush is this likely to be the problem as we both thought if the cold feed was blocked then nothing would get hot??

Any help would be apprieciated

 

[gas_man_gaz]

could be either! id guess the cold feed is blocked tho, ive had quite a few times where its circulated around the upstairs but not the downstairs.. but before ya chop it out try testing the pipework with a magnet if it sticks it shows there a build up of muck

 

[stuartguffy]

cheers mate will test and chop accordinly, I can sort if hear it struggling through the seperator.

 

[gas4you]

Check your pump first.

Upstairs could be being heated by gravity circulation if the pump is knackered and downstairs wont heat at all without the pump working.

 

[stuartguffy]

The pump was changed last night for a grunfoss and is the right way round.

cheers

 

[gas4you]

Have you an old check valve in the heating circuit that has stuck shut?

 

[stuartguffy]

not sure what would it look like? and be located is it like a gate valve or the isolation valves with the flat head screwdriver thing? Do not have a clue where it would be. Would a microbore system have one of these.

Thanks again