Rad not heating up fully

masterK

I have a radiator in my attic that doesn't heat up fully, only the bottom portion of it ever gets hot. I tried releasing the screw at the top with an allen key to let the air out. I could hear air being released for about 30 seconds after which it stopped, no water ever started to come out. I left the screw open for about 5 minutes.

The pipe into the radiator does be very hot suggesting it is just a problem with the radiator itself.

Any ideas?

JamesM

masterK wrote: »

I have a radiator in my attic that doesn't heat up fully, only the bottom portion of it ever gets hot. I tried releasing the screw at the top with an allen key to let the air out. I could hear air being released for about 30 seconds after which it stopped, no water ever started to come out. I left the screw open for about 5 minutes.

The pipe into the radiator does be very hot suggesting it is just a problem with the radiator itself.

Any ideas?

It's probably a sealed system - you need to let water into the system to push out the air. Lots of recent threads on this.
Jim.

crosstownk

JamesM wrote: »

It's probably a sealed system - you need to let water into the system to push out the air. Lots of recent threads on this.
Jim.

Yep.

You need to locate the filling valve and the pressure gauge. The gauge should read around 1bar when cold. If you bled the rad and did not refill then you may have made exacerbated the problem.

As the radiator in question is in the attic and probably the highest point in the system, it will require full pressure in order for it to get sufficient supply of hot water from the boiler.

wicklowlad

What you should do first is check what type of system you have as there are two types - a closed system where there is a pressure sphere beside the boiler (usually red!) and then the open system where there is a header tank in the attic. With the open system the ballcock in the header tank can stick in a closed position and therefore no water enters the system. Just check and if there is a tank just move the ballcock up and down a few time and water should start to fill the tank. Give it about 20 min and then bleed the radiator.

A heating system loses water by evaporation and that why it need a header tank.

If its a closed systen it may be that the spere has become full of water and you would need to get someone with experience to check it out.

masterK

Thanks for the help.

The radiator was only fitted about 18 months ago as part of an attic conversion. Will the filling valve and pressure gauge be near the boiler or are they on the radiator itself?

I do have a tank in the attic, not sure if it's a header tank or not. The house is about 8 years old

burger1979

that tank could be your cold water storage tank, how big is the tank that you can see? the filling valve and reg can be near the boiler if not there then try the hot press (its where mine is). if all else fails above that i would start to think along the lines of the pump in the boiler might not be powerful enough to pump the water that high, but i would rule out all other options before going down that road.

masterK

The tank is about 5 foot in length. I'd guess it's the cold water storage tank.

burger1979

yeah thats the cwst, the tank for the heating will be alot smaller, you should be able to lift it up with 2 hands.

wicklowlad

The header tank for the Heating is only a very small one. The water supply valve is either beside the boiler - if its a closed systen . You mentioned about the pump not being able to pump the water well some can be adjusted to increase flow of water. What you could also do is turn off the rads downstairs and see if the water circulated through the rad then - but the real problem sound like there is not enough water in the system.