why do i only get hot water from my vailiant combi boiler when the central heting is switched on. otherwise only cold water

debra anne poll, December 2006

You need to tell us what Vaillant it is... Some have flow switches and some have a servo valve...

Whatever the case... It will be the servo or flow-switch that has gone wrong...

Some can be really cheap and have "temp" fixes whilst others can be very expensive and complex.... Please be more descript with your appliance.

GasAid.co.uk, December 2006

The only advice i can offer you is to cheak the the heating control switch on your boiler sorry i cannot help any more.

wayne, December 2006