hot water

[hoot37]

hi
just looking for some advice on a problem i havent had before.
i have had a baxi backboiler for last 20 years (serviced every year)
well the problem was tonight put heating on for a few hours which worked fine,but the hot water from the cylinder was only luke warm.never had this problem before so put the controler on water only turned the boiler up to max after a hour the water is very hot so possible air lock for no unknown reason.
ther are NO diverter valves on the system just a pump,cylinder,controler and a boiler.
So was just wondering if it was anything to worry about,or just a one off air lock due to heating being used after sitting idle for the last few months
thanks

 

[spraggo]

Check the water level in the small head tank in loft, should be about one third full.

 

[hoot37]

thanks for reply
water in header is about half full
thanks