central heating-lossing pressure

4 Mar 2007
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United Kingdom
Hi, recently my boiler (18 months old condensing) stopped working. I had recently bled my rads and one rad was completely full of air. Filled up with water but boiler still did not work. Read the manual and checked the pressure on the boiler and pressure was low. Opened a valve and filled system to correct BAR pressure. Fired boiler up,bled rads,everything fine again. Spoke with someone and they said that i must have a leak in the system for the rads to fill up with air. I have checked everywhere and have noticed that a downstairs rad (also 18 months old) has a very slight leak at the bleed valve. The actual valve itself does not seem to open and close properly and there is an intermittent drop of water causing the carpet getting wet. Could this be the problem? If so, do i have to change rad? Or can i change the nut thingy that the bleed valve screws into? Pardon me for any incorrect terminology but not my trade im afraid.
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Drain down your system and remove the bleed valve, buy some PTFE tape from your local plumbers merchants. wrap it around your bleed thread roughly 5 times and tighten back up into your redaitor.

Represurise and observe.
The bleed valve can be easily replaced if you are going to drain down your system. As Red man said, one way to do it is to isolate the radiator (no need to drain the system down, just shut off both TRV and lockshield) remove the bleed valve pin and wrap some ptfe round it, screw back in and your job's done. But it is just as easy to get a replacement valve complete, and fit it. Here's one below, I can get them from my local City Plumbing merchants, you may source them from any reputable merchant yourself :)


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