On two occasions we've left our heating + hot water system switched off whilst going on holiday (a week each time) and on both times when the heating has been switched back on, the water tank (main one) has overflowed abrubtely... spitting the water out of the external overflow.
I'm just curious why this would happen? Is it normal?
Also we keep getting a air lock in the hot water tab in the kitchen which is furthest hot water tap from the hot water tank. The other hot water taps have no problem. Could this mean a leak or just poorly routed pipework to kitchen?
Try adjusting the ball valve in the CWT so the water level is lower.
Your kitchen tap could be drawing air into the pipework from the vent pipe. If you have an IV on the kitchen tap try restricting the flow from the tap by partly closing the IV.
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