DIY Doctor UK DIY Forums

Hi,
I live in a newish build house, and been having an issue with some air (i presume) in the heating system. All the radiators work just fine, except for 2 tall towel rail style radiators in the up stairs bathrooms. The bottom halves are hot, but the top halves are cold. I've tried bleeding them, to not much effect. Sometimes a small ammount of air is released, but more often, nothing seems to be released at all (air or water). they did work correctly at some point last year, but since I've had the heating on this winter the problem has occurred. If you bleed tham and no air comes out - what other option is there? Would I need more pressure in the system?
Thanks,
Phil

What type of heating system have you? Is it vented or pressurised? If it has header tanks where are they?

Hi Phil,

What pressure do you have now? + boiler make/model and as mush info as you can supply.

Right, thanks for replying - I'm no expert so please bear with me.
Boiler is a Potterton Suprima HE.
I just found some intructions behind the hot water tank that refer to it as an 'unvented hot water storage cylinder'. There are two other smaller tanks above it - one red, and one white, which i was once told deal with any excess pressure/water in the system?

I found two pressure guages near the water tank. One was just underneath the red expansion tank. it had two dials on it. The black dial points to 0. The red dial points to 1.5.

The other guage is on another pipe which i traced. It does eventually join up with a pipe that goes into the red tank, and where it goes into the wall, the plumber had marked the pipe as 'RTN'. The black dial on this guage pointed to '0' and the red one pointed to '2'.

Hope that helps.

I think you will find the red pointers on the dials are moveable, so ignore those.
The black pointers give the true pressure reading - by your post =0.

So you need to get some pressure in say 1.2bar only.

Read the MI's on how to do this or the projects section.

Hth

Ah - just the job. thanks for that info. Seems obvious now, as soon as I upped the pressure in the system a load of air came out of the radiator when i bled it and water went all the way to the tops of the towel rails.

Cheers chaps.