air in central heating system

ChippyJoe · Post by **ChippyJoe** » Tue Feb 25, 2025 12:35 am

hi all, this may sound a silly question ...
I get a build up of air in my system, particularly in one radiator, which I bleed out at the top of the radiator, which is fine for a week or so before gurgling and a cooler radiator occurs.
I know air can occur for a number of reasons, one major one is a leak somewhere in the pipes or connections.
If the system has a header tank, surely any leak would be constantly topped up and replaced by the header tank, and water leave by the place of the leak, rather than air drawn in ?
Can anyone help me understand ... many thanks

wine~o · Post by **wine~o** » Thu Feb 27, 2025 5:16 pm

Sounds like it could be corrosion , can cause a gas build up. fernox F1 can help prevent corrosion.

kirkie · Post by **kirkie** » Thu Feb 27, 2025 11:03 pm

If there's a small leak, air can still get in, even with a header tank. Check the system pressure and look for any hidden leaks.

Someone-Else · Post by **Someone-Else** » Thu Feb 27, 2025 11:17 pm

kirkie wrote: ↑Thu Feb 27, 2025 11:03 pmeven with a header tank. Check the system pressure

If it has a header tank, it will not have a system pressure gauge.

I would also suggest that the OP has already looked for large vegetables where they should not be.