Having a weird problem with what I believe is an airlock in my CH
system. It's a pumped system, and the rads aren't collecting much air
(been bled daily for about 3 weeks now) and appears to be working ok,
but the flow and return pipes to the boiler appear to be making a noise
like trickling water.
With the boiler output control cranked up, it occasionally blows out
the cut-out switch, so I've backed it down to half way successfully,
but the trickling noise remains.
When the boiler stops (and the pump cuts out too), I can hear water
almost sloshing back to the boiler making me think I have an airlock.
It occasionally 'phuts' and pops when it's been running for a while
(again, making me think there's air in the heat exchanger).
I've got a drain off cock on one of the pipes to the boiler, and when I
drained and refilled the system, it did let out quite a lot of air
before running water came out at a constant rate, but there's no drain
off on the other pipe (the flow I think). Perhaps trapped air in that
part of the system?
The only bleed valves not on the rads are on the pump (no air coming
out) and a capillary valve on a high point on the system (again, with
negligable air coming out).