Boiler making strange noise

[Chris The Deejay]

Hi, recently our boiler makes a really funny noise like a whale song/squeal for about 10 minutes at start up, then it goes away.
its loud enough to wake the family in the mornings

 

[hometech]

trapped air in the system

 

[Chris The Deejay]

trapped air in the system

Would draining and refilling the system help this problem

 

[cjg]

try turning the temp. down to 50, and run the boiler for a few hours, make sure your auto air vent is open.
then bleed all rads.

 

[hometech]

Would draining and refilling the system help this problem

It might but it seems a lot of effort on the off chance.
The noise is air inside the primary heat exchanger pipes so this suggests that the air is already setting at the boiler once the heating is stopped but the air is not being released by the valve at the boiler which suggests it's blocked or stuck closed.
Check the operation is as expected (a search for this will show you how) and you may have to replace it (not expensive)