Cold radiators

CFC

Could I have some help for the diy inept? My house has 5 radiators, 3 upstairs, 2 downstairs. 4 get warm. The ones downstairs are fine.

Upstairs, we have a problem. One is normal ie gets warm and can be turned up and down with the thermostat valve, and one gets red hot, cannot turn it down with the thermostat valve, and one (the one in my bedroom of course!!) does not warm up at all, it's stone cold. We've tried bleeding them, but I do not know if we're supposed to do it in any particular way or order.

Any advice would be appreciated, it's cold in the bedroom, leading me to have the heating on for longer than normal just trying to get a bit of warmth into it!

macman

So the one that can't be adjusted has probably a seized TRV, simple job to free if off or repalce it if necessary. Take the head off and see if you can move the pin underneath.
Bleed them with the system on and running, starting from downstairs work your way up.
If it's a combi system, is there adequate pressure-what does it say on the gauge?
If a conventional system, have you checked the expansion tank in the loft?-the ballcock may have stuck, preventing the system from topping up. Or of course the TRV on your bedroom may just have seized in the shut position.
Work through those to eliminate some of the options.

CFC

Aha thank you, will try taking the head off and see if anything is actually moving or whether it is just the knob moving. Also we didn't try bleeding them all in turn - will try that too.
I have a conventional type boiler. Once you start talking about checking expansion tanks though, you're getting a bit beyond my competency. I could check whether it looks low though probably - presumably it's a little tank, compared to a big water tank, yes?

macman

Yes, two tanks in your loft. big cold water tank feeding the cold taps, and little one feeding the CH. both are suppied by a ballcock. If the CH is off over the summer, that's when they seize and then the tanks runs low. Check the level, and push the ballcock down to seee if the water flows in OK. Often just a bit of waggling and a squirt of WD40 will be enough to free it off.