Cylinder thermostat l641 help

[ih]

Ian my bad not following instructions correctly! But am good and meter read as per your initial help!
If possible just to enlighten my knowledge on 3 port valve will appreciate your help!as mentioned earlier
I have st6400c programmer the switch on the valve stays mid position when hw or ch or both are demanded
Is this normal ? Should the switch motor to manual when only hw is demanded then return to mid position?
Thanking in advance

 

[ianmcd]

The valve should be in mid position when there is a demand for both CH and HW and both thermostats are calling for heat, , do you only have two wires in your Cyl stat, you should have three and you should have a wire in the HW off terminal on your programmer if you are using a mid position valve

 

[ih]

Thanks! I have 3 wires in cy stat! I need to learn how to check the wire in prog & report back!

 

[ianmcd]

the third wire in your Cyl stat is HW satisfied and should link to HW off in your programmer so you can have CH on its own without HW

 

[ih]

Sucess! Managed to open the programmer and yes there is the third wire in slot one which is hw off i also
Understand about having ch without hw! Final kindly confirm the 3 port valve is behaving as it should do i.e.
Staying on mid position if i have understood correctly then i think that is what you mean thanking for all your
Help kind regards
Ih