3 port valve (DM 5651 Actuator) Sunvic. 8 years of confusion

[spiceman]

Hello, I really hope somebody can help me out.

For the past 8 years Im really sure my heating and water system hasn't been working correctly. The reason I say this is because I thought the idea of a 3 port valve was either to heat the central heating and hot water together or individually.

On my system I can only heat hot water if the timeclock calls for it or central heating if its called for, never both together. I do have a 3 port valve and attached to this is a actuator called Duoval DM 5651. It has a 5 core cable connected to the junction box but not all the cores are used. The colours are Yellow,White,Blue,Orange and Earth. The Yellow core and Earth are not connected to anything.
I've tried looking for a Sunvic wiring diagram for this type of valve but cant find anything. Also looked at the honeywell website at the y plans diagram but some core colours are different.

Maybe I can't control both heating and hot water together with my type of system, I'm just really lost and need help..

Please if anyone can help it would be most appreciated.

Thanks Tony

 

[AfterburN003]

Sounds like u may have a wiring fault somewhere because u should definately be able to have hot waterand heating at the same time. If unsure about the wiring i would advise an electrician.

 

[petit_pablo]

What time switch/clock do you have? Is there a thermostat on the hw tank?

 

[spiceman]

I have Honeywell ST 799 programmer and Honeywell cylinder stat.
How would I get a wiring diagram for the actuator?

Im confident that I could wire it all up correctley if I knew more about the unit.

Thank you.

 

[petit_pablo]

It should be:

Yellow - HW off (From timer and Cyl stat)
White - CH on (From Room thermostat or timer if no stat fitted)
Orange - To pump & boiler or just boiler if boiler controls pump)
Blue - Neutral
Yellow/Green - Earth

 

[AfterburN003]

I dont think the recent Sunvic valve wiring diagrams differ from the older ones. Ifu can find a new wiring diagram on the web it may help u.

 

[spiceman]

It should be:

Yellow - HW off (From timer and Cyl stat)
White - CH on (From Room thermostat or timer if no stat fitted)
Orange - To pump & boiler or just boiler if boiler controls pump)
Blue - Neutral
Yellow/Green - Earth

Thanks very much for your help, all of you.

Petit Pablo. Would I be correct in saying that the yellow core does the same as the grey core on the Sundial Y plan honeywell actuator.

Thanks

 

[petit_pablo]

Thanks very much for your help, all of you.

Petit Pablo. Would I be correct in saying that the yellow core does the same as the grey core on the Sundial Y plan honeywell actuator.

Thanks

Yep

 

[spiceman]

Cheers. Oh 1 more thing, Sorry for being a pain.
Why is it we need a wire coming from the cylinder stat, terminal 7 on the honeywell y plan going all the way back to the time controller labled HW Off, any reason?

Thanks

 

[petit_pablo]

You dont, you just need a wire from HW off on the timer and one from the cyl stat satisfied going to the yellow of your valve.

Its just how the diagram is drawn

 

[spiceman]

So I do need a wire from the HW off on the time controller going to the yellow of the valve and cylinder stat. What does this do? I mean by turning the Hw switch to off on the controller?

How comes the diagram doesn't show the same for heating?

Thanks

 

[petit_pablo]

So I do need a wire from the HW off on the time controller going to the yellow of the valve and cylinder stat. YES

What does this do? I mean by turning the Hw switch to off on the controller? It puts power on the yellow moving the valve for CH.

How comes the diagram doesn't show the same for heating? Heating doesnt require an off

Thanks

 

[spiceman]

Great, You have been most helpful to me. Will be doing a complete rewire of my system in a few days. Hopefully after all these years I can get it to work correctly.

Cheers

 

[petit_pablo]

Good luck! Recommend getting a new wiring centre if your current one is just a bunch of wires.

 

[MANDATE]

Afraid it gets quite complicated. When HW is called for alone the boiler is supplied with power from the cylinder stat. The valve does not play an active role.
If CH is also called for while HW is still called for, the room stat supplies power to the valves white wire. This powers the motor until microswitch is triggered at mid position. There is no power on the 'grey' or 'yellow' in your case, so the valve stays at mid position. Boiler still being supplied power from cyinder stat.
When HW is satisfied (or turned off) the cylinder stat is out of action in supplying power. Two actions are required for the sysytem to continue.
First the valve must move from mid position to CH only and power must be supplied to the boiler.
The cylinder stat is of a two mode, so power that was going to boiler is diverted to the valves 'grey' and when this is live it takes over from the white and moves the valve over the final stage. This diversion wont work if HW was never on, so alternative is introduced coming direct from the programmers HW switch (another two way). The wire coming from the OFF terminal. It does not matter if this wire is fixed direct to the valves 'grey' or the cylinder stat terminal fixed to the 'grey'.
During the valves travel over this stage a 2nd microswitch is triggered which allows power supplied from the room stat out through the valves 'orange' wire to power the boiler.

The usual problems associated with 3 ports are (a) the valve not moving beyond mid position or (b) it does move correctly but boiler fails to light