radiators going cold

[trekie]

a radiator in the bedroom is only heating up half way, despite frequent bleeding. i have tried turning off the rad and then turning it on full but to no avail. can anyone help

 

[NiallA]

a radiator in the bedroom is only heating up half way, despite frequent bleeding. i have tried turning off the rad and then turning it on full but to no avail. can anyone help

When you bleed the rad, do you get much air? does the rad heat up fully then for a while.
If yes, then your system is dragging in air somewhere if it is an open system or you might have a leak if it is a closed system.

An open system has a small expansion tank in the attic with a ballcock and overflow pipe in it. When the water heats up it expands up the overflow pipe and if it gets exceptionally hot, it can boil over so to speak. This type of system is required where you have a solid fuel boiler (ie back boiler in a fireplace). You can however also have this sytem in a gas or oil fired system. In this case air can be introduced in the system by water boiling over into the expansion or if your pump is configured wrong, water is pumped through the tank. This air then collects in one of the rads, (usually the last in the system).

A closed system doesn't have a storage tank and overflow, but has an expansion vessel instead. This can only be used on a oil or gas system as a thermostat can control the water temp. In this case, a gate valve controls the water feed (as opposed to a ballcock) and manually allows water in to fill the system. If this is the case try refilling the water in the system (check the pressure gauge so as not to overfill the system) and see if that cures your problem. If it then recurrs you must have a leak.

 

[Brenbo]

Is the rad installed for long?
If so it is probably clod up with dirty. Especially if cold in the center.
Try draining your system. Should that not work you will need to remove the rad and flush it out or fit a new one.

 

[car]

anything here