hot water from overflow

[scotty6]

I have an open vented hot water system heated by a heat exchanger from the boiler. The heat exchanging system is venting into it\\\'s feed + expansion tank when hot water is swiched on at the timer (which I think it is supposed to?). The water is not being drawn away quickly enough (it is being drawn away as I can feel the other pipe moving) though and because of this it is going out through the overflow pipe. Any idea what could cause this?

PS.
The bottom of my f&e tank is level with the bottom of the cold water tank - they both sit on the same piece of wood. Hot water looks clean. Ball valve is dripping but only slightly - fixing this separately
Thanks,

 

[stucky]

I have an open vented hot water system heated by a heat exchanger from the boiler. The heat exchanging system is venting into it\\\'s feed + expansion tank when hot water is swiched on at the timer (which I think it is supposed to?). The water is not being drawn away quickly enough (it is being drawn away as I can feel the other pipe moving) though and because of this it is going out through the overflow pipe. Any idea what could cause this?

PS.
The bottom of my f&e tank is level with the bottom of the cold water tank - they both sit on the same piece of wood. Hot water looks clean. Ball valve is dripping but only slightly - fixing this separately
Thanks,

raise the expansion tank above feed

 

[Kingsway]

Boiler thermostat faulty
Coil in Cylinder broken and leaking
Ballvalve in Exp tank dripping
Pump speed to high
Blockage in System
Pump installed in correctly