Cental heating not working downstairs.

[stuff]

Hi all,

I've recently had to change the central heating pump because it was not pumping hot water to the radiators. I tried turning the pump but could not so I had to change the pump.

After changing the pump, the radiator upstairs was heating up just fine but the radiators downstairs is cold. Can somebody suggest how I can get all radiators working? Thanks in advance for any useful advice.

[OldBill]

Did you bleed all the rads starting with the downstairs ones?

[DIY]

Did you drain the system and refill with water and inhibitor, or did you just isolate the pump to replace it? If you drained and refilled then the CH may need to be switched on for an hour or two, and all rads bled of air, to remove air from the system. If you have done this and there is no improvement the next thing is to turn the upstairs rad(s) off and see if that results in the downstairs rads heating up. If the downstairs rads heat up you should then turn the upstairs rads back on. If that results in the upstairs rads getting hot but the downstairs rads get cold, that suggests that the rads need balancing by adjusting their lockshield valves.

[stuff]

I drained the system by tying the float and draining the radiators and opening the bleed tap on the upstairs radiators then installed a new pump and pump valves as the old one was leaking

I have bled the upstairs then downstairs. i'll try to bleed it again.

Thanks for your help.

[stuff]

I drained the system by tying the float and draining the radiators and opening the bleed tap on the upstairs radiators then installed a new pump and pump valves as the old one was leaking

I have bled the upstairs then downstairs. i'll try to bleed it again.

i did read up on the balancing bit. i'll do that next.

Thanks for your help.

[DIY]

You haven't mentioned draining the downstairs rads, or turning the upstairs rads off to see if that results in the downstairs rads getting hot. Is it possible that there is a sludge blockage somewhere on the downstairs circuit? Balancing seems pointless unless you are sure that three are no blockages anywhere.

[stuff]

that's what i thought, how can I check, and how do i unblock it? would the raditors need to be removed?

[stuff]

that's what i thought, how can I check, and how do i unblock it? would the raditors need to be removed?

[DIY]

If there isn't a drainage tap on any of the downstairs pipes then you will have to turn off a radiator and somehow attach a hose pipe and run that to an outside drain. If you then allow water to enter the header tank it should then flush out the system. If it doesn't then there might be a blockage due to sludge so power flushing might be needed. What effect does running the system with all the upstairs rads turned off? Do any of the downstairs rads warm up?

[stuff]

Just wanna say a big THANK YOU to DIY. My central heating is now working again.