3 port valve

[rosie]

Hi ,when my central heating goes off in the evening the 3 port valve does not close off and ther is a humming and a vibration from even hours after wards.
the only way to stop it is to turn off the electric and the valve closes. i turn the electic back on and no noise, no vibration.
Its a new boiler 18 months old, had plumbers to try and fix it fittting 2 new pumps and 2 new 3 port vavles.HELP

 

[buckley plumb]

Hi ,when my central heating goes off in the evening the 3 port valve does not close off and ther is a humming and a vibration from even hours after wards.
the only way to stop it is to turn off the electric and the valve closes. i turn the electic back on and no noise, no vibration.
Its a new boiler 18 months old, had plumbers to try and fix it fittting 2 new pumps and 2 new 3 port vavles.HELP

3 port mid position valves always stop in the last mode they were in. eg if in hw then would stop there they only spring return when the power is turned off.