Cold downstairs radiators !! upstairs are OK !! Furred Up ?

[gazzaman]

Hi, just moved into a new house ( not newly built) my radiators are fed by what I belive to be called Micro Borepipe ( 10mm external 8mm internal )
My upstairs radiators are fine but downstairs do not get warm at all not even at the feed pipes !
I dont expect there to be any sort of isolation valve to be between the 2 circuits anyone any ideas ??
I read on another forum that the possible cause is furred up pipe blockage ?? this seems strange to affect all rads ??
and also that only solution is total pipe replacement ?
if this is the problem is there no chemicals on the market I could drain system down and fill with that would dissolve the furring ??
thanks in advance
G

[htg engineer]

The pump will need to be changed or it might be stuck. Upstairs will heat up by gravity, but the pump has to work to pump the water to the downstairs radiators.

[gazzaman]

Thanks for the reply, I thought the pump was OK as it works for the hot water also ??
Is this not the case ??
when hot water is first turned on pump starts a bit noisey then settles after about 30 seconds or so.
If the pump was no good would the hot water cylinder still fill ?

[htg engineer]

The pump has nothing to do with the hot water cylinder filling, is it a fully pumped system, If not then the pump has nothing to do with the hot water just the heating.

[gazzaman]

Yes I think its a fully pumped system, I have a 3 port valve just infront of my pump so that makes it a fully pumped system ? right ?

[htg engineer]

yes it's a fully pumped system. put pump on highest setting and turn all radiators off upstairs, this should push the heat through to downstairs. It could just be airlocked. Double check all radiator valves are open.

You could also check that the 3 port valve is opening fully, the actuator may be slipping on the spindle. Remove the motorised valve head, and turn the spindle manually.

[htg engineer]

Could just be airlocked.

Yes its a fully pumped system then, check the pump is on the maximum setting (lll) then turn off all upstairs radiators (via radiator valves) and turn on heating only, this should push the heat through to downstairs.

If this doesn't work, or you get one or two not heating, turn off all radiators, apart from one and see if this pushes it through.

[andy.blackpool]

If there's nothing wrong with the pump,try partly closing the valves on the upstairs rads while fully opening the downstairs ones. I don't mean the thermostatic valves, I mean the ones on the other side of the rads. This'll cause more water to feed the downstairs rads

[gazzaman]

Thanks, I guess it was an air lock.
its working now !!
apart from the large radiator in the living room.
I will have to try partly closing the valves to balance the system to get this one warm !!