Hot water in the expansion tank.

[bcampestris]

Hi,

My open system central heating header tank was getting really hot. I've turned down the pump and adjusted the balance between the hot water and central heating zones. This had reduced the water to 'tepid'.

However, every time the heating thermostat cuts out I still get a splash of water into the tank. Is this normal? I suppose the splash is about 1/8 of a pint.

 

[Mike Jackson]

This is known as pumping over and is incorrect. Left uncorrected it will lead to corrosion in the system. It may be due to a partial blockage in the pipework or it may just be that the vent needs raising.

Mike