Big Phil wrote:
"James Salisbury" wrote in
message ...

Do you have thermostatic valves on the radiators, these can whissle
and moan
as they close.
It may be that the pump speed is too high, sending the water round
the
radiators too fast,
try turning the speed down one notch and also balalancing the
system, see
the FAQ for this group.

I had a whistleing noise from the rads and did the above and that
sorted them fine. However, that was only once the heating had been on
for a while and the TRV's were closing, if the noise it at the start
then it's probably something else like air in the boiler.

No TRVs on the system. This morning, I jumped out of bed to investigate. The
boiler itself was making some noise, and I discovered that it stopped and
restarted 3 or 4 times in a row. After it stopped, changing the boiler's
thermostat made no difference whatsoever, so it had probably cut out. My
guess is that there is an air lock in the boiler that causes problems at the
start - after a while, the pump has managed to push enough water into the
boiler for it to work properly... I now have to work out how to get the air
out of the system. There is a valve directly above the boiler, on the "flow"
side - I twisted it this morning, but there was just water coming out. I
will have to check for any other valves...

I would love to know how the air gets to the boiler that causes these
problems - which are only when the system starts up in the morning. Perhaps
there is some problem with the boiler itself??

Alex

PS Where's the FAQ for this group located, please?