2 hot radiators, the rest are cold?!

[Solveig]

I have only lived in my house since April, and have now got a problem with my central heating. It was working fine when we first moved in, then we haven't used it all summer, and now that I wanted to turn the heating on the following happens: 2 of the upstairs radiators are hot, but all the rest are cold? Could it be that the cold ones just need bleeding? Or could it be due to something else?

 

[breezer]

have you not tried bleeding them? also while our "resident" heating people are not here they will want to know what type of boiler do you have, i.e combi, back or pumped or what ever.

one thing is for sure you should bleed the rads with the system off

 

[Solveig]

Thanks for your reply. I have not tried bleeding them yet, but the plan is to do that today before I phone an engineer! It is a back boiler, and so far I have not even seen it (!) as the boiler and pump are behind my chimneybreast and I would have to take off a panel on the side to get to them. It is operated from the gas fireplace, so all I have ever done is re-light the pilot light from the front a couple of times. Other than that I don't know a thing about it - there's no instructionbook to be found anywhere either...

 

[ollski]

are the two hot radiators the two nearest to your circulating pump, probably in the airing cupboard with the hot water cylinder?. If so you need a new pump.

 

[MANDATE]

If your pump is capable of pumping water upstairs then I would not suspect it as being in need of replacement, but it may need bleeding.
If you have no joy after bleeding the radiators you could try closing the hot ones down to see what effect the pump has on the others.
Remember that sometimes the bathroom radiator is on the hot water side of the system and is not related to the pump, that is I'm assuming you do not have a fully pumped system with motorised valve
Also feel at the pipes below the inlet valve, if they are hot then the radiator is starved of water circulation due to sludge or air.

 

[corgiman]

If your pump is capable of pumping water upstairs then I would not suspect it as being in need of replacement, but it may need bleeding.:

Sorry your wrong mandate as the rads near pump will heat up via gravity

if the rads were getting hot downstairs the it would be impossible for the pump to be at fault but not in this case I totally agree with ollski

PS why do you put at the end of your posts??

 

[MANDATE]

I don't disagree that radiators may heat up by gravity, but a pump does not need replacing if it is capable of pumping water upstairs in my opinion.
If it's not capable then what's the reason?
depending on the reason depends on whether or not you replace it
Oilskis solution at the end of the day might be be the correct one but a pump that has not been in use for some time may just be a sticking and needs releasing or it may need bleeding.
Of course this is 'my opinion only'
I like what in my opinion represents.
Why do you ask ?

 

[corgiman]

I don't disagree that radiators may heat up by gravity, but a pump does not need replacing if it is capable of pumping water upstairs in my opinion.
If it's not capable then what's the reason?
depending on the reason depends on whether or not you replace it
Oilskis solution at the end of the day might be be the correct one but a pump that has not been in use for some time may just be a sticking and needs releasing or it may need bleeding.
Of course this is 'my opinion only'
I like what in my opinion represents.
Why do you ask ?

that would be true mate if all the rads upstairs were heating up,
I am not saying replace the pump either just saying that it should be the first port of call,

as for the I just wondered. Each to his own i suppose

 

[ChrisR]

Two upstairs rads hot? Certainly the Pump IS suspect! Undo the big screw in the middle - may have a slot or a knob. If slot type, insert smallish flat screwdriver and turn shaft - unless it's already turning. If knob type you pull a little and do the twisting. That can often get a stuck pump turning.

Gravity circulation will go through a stationary pump.