wierd central heating ?!!

dandowding

Having just turned on the central heating after not really using it for the summer I seem to have a bit of a problem ...... The hot water seems to be scalding hot (hotter than normal) and not all the rads are getting hot. Upstairs seem ok, but the downstairs ones are either stone cold or barely tepid !?!
The system is indirect with hot water cylinder in the airing cupboard and expansion tank in the loft.

The pump is still running, and I have tried shutting off rads to try to concentrate a flow thru the colder ones, but no joy !

Any ideas greatly appreciated...and needed !!

Thanks
DD

keith1950

Hi, could possibly be the 3 way valve ( if you have one ), if it is stuck in the hot water position the pump will keep running because the room thermostat will be asking for heat and the room will not get hot enough to turn off the heating. There is sometimes a manual overide which could prove it one way or another.

dandowding

Would this 3 way valve, if it isn't working, not just stop the flow to all c.h ?? the upstairs rads are all hot ?!!

adaze

Have you tried bleeding all the radiators?

It could depend on where the 3 way valve is stuck, and could be restricting the flow? Sounds more like air to me though.