Air in pump?

[andyste]

My parents recently had a new boiler fitted. The new one has been sited elsewhere in the house, resulting in some changes to the airing cupboard pipework. Since the work was done they've been getting air in the system - the CH comes on early evening but the pump gradually becomes more noisy, and needs bleeding after a couple of hours.

The airing cupboard pipework is at floor level so the expansion pipe is 9ft+ up to the top of the tank, so is air likely to come down this way? If not, where else could the air be coming from?

For info, this is the sequence of "fittings" in the airing cupboard pipework:-
Boiler -> bottle air valve -> 22mm expansion pipe -> 15mm feed pipe -> pump -> 3-way valve (then off to tank & rads).

There was originally an air tower in the "old" pipework but was told they're not really necessary, so it was removed as part of this recent work. Would it help to put one back in?

 

[craftor]

Not being an expert, I had the same noisy pump/system when the water got hotter after changing from gravity fed HW/ pumped CH to fully pumped

The boiler was re sited to the garage from the kitchen. The problem was the returns were teed off too far away from the boiler( just underneath the HW cylinder). They should be close to the boiler apparently

 

[45yearsagasman]

I'll leave you in the hands of the experts.