Heating/Hot Water problems

[carlsbergy]

When I select 'ch only' on my control unit the lever on the three port valve moves over to 'H' and the pump switches on/off according to the thermostat telling the pump when the room has reached/not reached temperature. When I select 'hw only' on my control unit (central heating off) the lever on the valve moves to 'W' and heats the water in the tank until it reaches temperature fine.

When I select 'ch and hw' the lever on the valve moves to 'H' and central heating is on fine, when the room thermostat clicks off, the lever stays in the 'H' position and the pump on, the heating stays on and the lever does not move over to heat the water.

I then selected the 'hw' off and put 'ch' on, which by itself works fine on and off according to the thermostat, when I turned the thermostat down the pump clicked off, I then switched 'hw' on via the control unit, the lever on the valve stays on 'h' and the pump starts heating up the rads even though the thermostat is not on.

Any ideas please - I did post earlier last week but this is now a better detailed description of fault.

 

[Slugbabydotcom]

Compare your wiring to the y plan system.

I have 3 ideas and could get to the bottom of it much easier if I was looking at it.

1 The microswitch in your diverter valve is sticking.

2 Your Cylinder stat has a fault or is not wired correctly.

3 DV malfunction

Sorry I can't work out the intricacies of it now. I'm really tired, its nearly dawn and I need to get in my coffin. I just had to reply because no one else has.

Heres a little bit more to help you suss it out

Look at DV wiring, forget about neutral and earth just follow the live

White wire live = CH call
grey wire live = HW call
orange wire live = boiler and pump run
Theres some tricky wiring in the cyl stat which I have difficulty explaining right now [too tired] perhaps some one else can help out?

 

[carlsbergy]

Thanks for replying, will go through your answers over Christmas, luckily I can operate CH and HW even though not together.

 

[ChrisR]

White wire live = CH call
grey wire live = HW call
orange wire live = boiler and pump run

Neigh lad,
grey wire live, either from programmer or cyl stat, = HW OFF

 

[Slugbabydotcom]

Cheers Chris I was just too tired to make sense and get it into words properly.