air in my boiler

[Hazelb]

It's that time of year again!

I've got a central heating system with two heating zones, and a hot water circuit.

The rads rarely need bleeing and the expansion tank is full, but the boiler seems prone to getting air in it. ( thumping banging- happens mainly when the pump shuts off ).

How to I bleed air from the boiler, or should there be an automatic air vent somewhere in it?

It's a 20yr old Baxi solo

 

[D_Hailsham]

the boiler seems prone to getting air in it. ( thumping banging- happens mainly when the pump shuts off ).

It's a 20yr old Baxi solo

May not be air; could be the pump is not running on long enough after the boiler goes out, so the boiler is overheating.

Which model Baxi Solo do you have - there are a lot to choose from. The GC number would help. It starts with 41.