IS it normal to paralell the DHW Actuator switch with CH Room Stat ?

Hi guys


I have a problem with my Central Heating. Central Heating does not fire up when Room Stat is calling for heat. I think the problem is with my Central Heating Actuator.

Sequence is -
Heating Demand
Actuator motor rotates to "B" - open.
Boiler does not fire.


Boiler fires every time there is a HW demand.

When I look at wiring joint box I notice the Hot Water Actuator wiring and and the Central Heating Actuator wiring are linked,

Grey wire from HW Actuator and Grey wire from CH actuator are both connected.
Orange wire from HW Actuator and orange wire from CH actuator are both connected.

Is this normal.

I have a Performa 28e boiler which allows setting the control knob to either HW plus CH or
just HW.

Looks like the installation engineers thought they would just put a boiler demand on the CH input and not the HW input. IS this a regular practise?

Many thanks
Cheers

The orange and grey wires are connected to a micro switch in the actuators when the valve opens it activates the switch which in turn fires the boiler up. From your description it sounds like the switch in the heating valve has failed. Depending on the type of valve you may be able to replace just the actuator but some types you will have to replace the complete valve.

Grey is permanent live into the actuator which is why they're connected together

Orange is switched live out of the actuator, IE the live that turns the boiler on, which is why they're connected together

The browns are the wires that will be connected differently to give you independent control of heating and hot water

Is this a combi boiler with a hot water cylinder as well?

Or a system boiler which still has the combi knobs?

Tony