when hot water on heating is too although not selected 2b Help and information on all topics relating to your central heating, air conditioning and ventilation issues.

[wired1]

:( Either by using the timer or manual selection, when the hot water is on the heating now comes on even though it hasn't been selected. The timer/control unit only shows the hot water as being on. Is this a faulty timer/control unit :?:

[htg engineer]

Possibly - but more likely to be a faulty motorised valve.

The motorised valve sits on top of a three port valve. You have flow from boiler AB, Central Heating port A, Hot Water port B.

When CH only is selected the motor turns to open one port A, HW only selected it will turn to open the other port B. HW and CH it will open ports A and B.

Also check 3 port valve spindle turns freely.

htg

[wired1]

Thanks for that. I have located the actuator - cleverly placed so that it is tightly fitted onto the 3 pins of the pipework and between a joist. I can't see the make, begins with Lys...... I think - unit about 16 years old!. At the side a black lever 'was' almost hanging out of the case but as I got hold of it, it pushed into the case and I can't get it free now. The radiators are very hot but I'm assuming that this is becaue there is no thermostatic control over them due to the heating not actually being selected via the timer unit. Would this be correct? If I remove the actuator - white box - do I have to close off the water supply via the various pipes to the unit or is it just a case of taking it off? I understand how the motorised bit works the valves but I'm not sure what is actually faulty and how the components of the actuator physically work the pipework connection.