Think we may have a jammed pump, or similar, as hot water is hot, radiators are not. Have read new foresters reply to a similar problem previously, but he suggests turning the heating off, before attempting to unjam the pump. As ours is a solid fuel system, it's not easy to do this, and with a young baby, I'm loathed to let the fire go out until I have to. Any suggestions? I'm going to call out a plumber or two for some quotes....just wanted to know if there was anything I could reasonably try first.
You will probably have an electrically operated valve which is connected to your main house thermostat where you set the heat for the house - often in hallway. If this jams off there may be a manual override on the valve itself. It may also be that the pump itself is a bit furred up in which case a sharp but not too hard tap with a hammer may loosen the impeller. This often happens after the pump has been idle through the summer months. If neither works the plumber is a very good solution!
In your case I'd say turn off just the pump, if you have one. Solid fuel systems should keep working the hot water by convection, so you shouldn't get any explosions...
If you do have a pump, my previous solution may work, or the gentle tap with a hammer.
JSB's valve idea is also worth looking at (our hybrid gas-solid system just has such a valve on the hot water). Of course it could also be a faulty controller, or a master room thermostat being set too low.
As already stated most common fault is stuck pump after long period of non use, if a sharp tap with hammer don't work. Turn off and undo large screw plug in centre of pump housing (silver with large slot) might get a very small amount ot water but no worry, insert flat bladed screwdriver in hole and turn impellor inside, refit and turn on.