Strange Central Heating problem

[pyounger]

I have a conventional CH system - header tank in loft. The radiators are all pumped except for the one in the bathroom which is linked to the hot water cylinder and they are gravity fed.

This morning an odd thing happened. I have the timer/boiler just set for the hot water, this morning I noticed the radiator in all the upstairs bedrooms where also on, as well as the hot water (and, of course, the radiator in the bathroom). This has never happened before. The timer indicates that only the hot water is on, and all the downstairs radiators were stone cold.

If I only have the timer set to switch on the hot water, then that and the bathroom radiator, is usually all that comes on.

can anyone explain what’s going on?

 

[Nozzle]

Motorised diverter valve stuck open.

Nozzle

 

[pyounger]

I’m just about to start getting quotes for a new boiler, is there any harm in leaving it as it is until it’s changed or should I get it fixed immediately

 

[oldbutnotdead]

Not a disaster, if you're looking at a new system not worth the chew repairing. Just turn the other upstairs rads off.

 

[pyounger]

Thanks, that’s what I was thinking

 

[oilhead]

If hot water is on gravity, you wont have a diverter valve. If the pipework is not configured correctly, you will get thermal transfer into the radiators upstairs through the return pipework.

 

[transam]

Duff nrv / check valve

if it’s gravity hot water pumped heating ????