Air entering CH via Feed and expansion tank

[DaveAngel]

Can anybody help?

I have an old baxi back boiler.

Recently air is being sucked in via the feed and expansion open outlet (tested by placing a cup of water underneeth which is sucked up)

the system spurts boiling water from this pipe every five or so minunets.

YOur thoughts are very much appreciated

 

[ChrisR]

If things have changed, it's probably due to deposits building up in the pipes - where the feed meets the main pipes.
Often only solved by cutting and replacing or poking out hte pipes in that area.

Also its likely that the original design was not what would be recommended now. Needs someone to view to see what goes where - not necessarily an easy thing to do!

 

[DaveAngel]

Many thanks,

will try a chem wash before looking for cold spots and replacing pipe.