Annoying radiator problem

[Pete L]

System with ten rads. Timer turns on rads at 0600 and everything works fine. House nice and warm. System goes off at 1100 and comes back on at

1500. Then the upstairs rads are hot but downstairs stay cold. About an hour ago I turned off all of upstairs and the downstairs ones are just about beginging to warm up. I'm at a loss to understand why this should be. The only difference between early morning and afternoon is that the temperature is lower from night cooling but so what? The thermostat is normally set at about 20 degs and I've turned it up to 25 but I can't see how that can coax the system into warming up the downstairs rads. Anybody any useful suggestions or ideas please?

[Roger Mills]

Whereabouts is the thermostat?

[Pete L]

Thermostat is in the hallway. I thought perhaps this was the problem. The gasman came and put a new one in the other day. He couldn't find anything wrong with the system. This doesn't explain why the downstairs rads don't come on in the afternoon when the upstairs ones are fine. Somebody suggested that it is because during the day hot water is used whilst at night the tank is full. I don't quite understand that since I thought the rads were indeopendent of the hot water tank.

[Roger Mills]

OK, tell us a bit more about the design of your system. Are there any motorised valves? If so, how many, and what type (2-port or 3-port). Is the pipework to the upstairs and downstairs radiators separate, or a single loop? [Clue: if you have wooden floors downstairs, with the pipework *below* the floor, they will be separate. If you have solid floors downstairs, there will *probably* be only one circuit, between the floors - with pipes going up to the upstairs rads and down to the downstairs rads.] Does the pump run when you are *just* heating the HW, with the CH off?

A photo of the pipework going to the HW cylinder would help - particularly if the pump and any motorised valves were also shown on it.

If you have a single pump and separate upstairs and downstairs circuits (even though not separately switchable) it could be a balancing issue - and the relative flow through the up and down circuits could well be affected by whether or not the HW was being heated at the same time. But maybe I'm pre-empting the answers to some of the abovce questions . .

[Pete L]

No If so, how many, and what type (2-port or 3-port). Is the

Upstairs are wooden but downstairs are solid since the pipes to the rads just run along the skirting board.

Yes - but with the CH on I can hear the pump whirling and feel water running through the pipes.

I suspect it is just a balancing problem. Its near 5pm now and upstairs rads are running hot yet downstairs things are chilly - my thermometer says 19 degs. The thermostat is on 21 which is past the 'click' you feel as you turn it. The system is pretty old. I did some draining and put in some de-sludgger stuff in a couple of weeks ago and replaced it after a few days with inhibitor. Thanks for your help and interest! Pete