Few weeks back I awoke to no hot water, I have a baxi 24 HE on an open system, boiler had tripped so reset next day same thing few days later I had a look and realised the pump had stopped, so bought a new pump, changed it and up and running but the system sounds like it is full of air wooshing around, banging and tripping the boiler constantly, sometimes It might last for 2 days. I have checked the F&E tank and you can see the water coming in as it expands but it is just luke warm not hot, i have a drip from an overflow but both tanks levels look OK, bleeding highest rads everyday to clear air. I am now very confusedto the cause, any suggestions?