diverter actuator not working correctly :(

[marcel808]

hi
a week ago, we started to see problems with the central heating. When the central heating switches on, nothing happens. When the hot water is switched on, both hot water and central heating start working.
I assumed it was a problem with the diverter valve (we have a Drayton MAI/679-3 mid position diverter).
I changed the front electrical part (the actuator), I havent touched the water diverter valve because it seems to turn easily.
After changing the actuator, no change, exactly the same results.
Is really confusing me 🙂 If I check the voltages, when the hot water on signal goes to 240v, that connects straight to the orange wire (boiler on I assume) and the boiler starts. But when the white (central heating on I assume) has 240v, the orange (boiler on I assume) is 0v. Does the actuator look for the white wire 240v, turn the motor then set the orange wire to 240v?
Even when I take the actuator off the valve, the motor cannot move to just central heating. See attached photo, even using the manual level on the side of the actuator, it can only move between W (water) and M (both water and heating). I cannot ever get it to turn to H (just central heating). Its a brand new actuator, doing exactly the same as the old actuator I took off. I'm really confused 🙂
many thanks for any advice

 

[lame plumber]

try looking and seeing if the room stat is working correctly first.

 

[marcel808]

hi lame plumber
I don't have a room thermostat, just a Tado (which has its own wireless thermostat).
Tado sends 240v to the orange wire for hot water and 240v to the white wire for central heating.
thanks

 

[kozak1968]

What programmer do you have?

 

[marcel808]

hi Kozak1968
no programmer, it uses Tado (like Nest and Hive), it tries to keep the temperature of the house constant
thanks

 

[stani]

Why do you have 2 mid position valves.

 

[marcel808]

do you mean the photo? 🙂
Its the same diverter, 2 photos side by side

 

[ShaunCorbs]

have you double checked your wiring ?

 

[stani]

Sorry, thought it was two valves. if you take the head off does the valve spindle turn freely? And have you put the wires back exactly as they were?

 

[marcel808]

sorted 🙂
The HW OFF wire was not connected up. I found a useful Y-Plan diagram that showed the central heating only fires up when 230v on white AND grey (white being central heating on and grey being hot water off).
many many thanks

 

[GasmanxxxR1]

A happy ending