changing heating controls

[smiffyuk]

I have just purchased the following items to change from a smartfit y plan
v4073 valve, cm927 stat, cylinder stat and sunvic wiring box.
I've been reading the various items concerning the cm 927 used on a y plan system and as I haven't got a cheap programmer would it be alright to use a standard 2 way plate switch to control the dhw as I generally put the dhw on when I want it .
Any advice will be welcomed

 

[D_Hailsham]

I have just purchased the following items to change from a smartfit y plan: v4073 valve, cm927 stat, cylinder stat and sunvic wiring box.

Are you saying that you already have a Smartfit Y Plan and have bought the components so you can change to a standard Y plan?

If so, then you could use a two way switch to turn the hot water on and off. The common terminal should be connected to the live terminal in the wiring box, the ON terminal to the cylinder stat Common and the OFF terminal to the Valve grey. The two positions of the switch then mimic the HW ON and HW OFF terminals of a time switch. The cylinder stat satisfied terminal would also connect to the grey wire, as in the wiring diagrams.

 

[smiffyuk]

Hi Thanks for the info Yes I have a smartfit y plan but it causes me problems I've had three room units in 8 years so I thought I would change to a standard y plan using the programmable thermostat instead.
One more question I purchased a sundial wiring box but it has one more connection to the mid position valve than the valve actually has It's showing a red wire 6 in total but my valve only has 5 wires . I assume that as the box is prewired I will have to get the standard ten connector box instead.
Again thanks for the assistance

 

[D_Hailsham]

I purchased a sundial wiring box but it has one more connection to the mid position valve than the valve actually has It's showing a red wire 6 in total but my valve only has 5 wires. I assume that as the box is prewired I will have to get the standard ten connector box instead.

Do you mean a Honeywell Sundial box or a Sunvic box? Honeywell only make two boxes; one contains a strip of ten connectors. The other has a series of connectors already labelled for the different devices. According to the latest info, this box does not have a connection for a red wire; so I am confused.

 

[smiffyuk]

Hi Yes I was confused as well The box is labelled sundial plan no42005748-001
I purchased it with the stat and valve from a heating controls web site but the strip to connect the mid position valve to has 6 connectors one being the red wire which doesnot appear on the valve I think I was sold old stock And I might have to purchase a new box.
Thanks anyway

 

[D_Hailsham]

Hi Yes I was confused as well The box is labelled sundial plan no42005748-001

Iinstructions for the Honeywell Sundial Wiring Centre. Does yours look anything like this? If not, it's not what it says on the box! In which case, go back to the supplier and demand a new one.

 

[smiffyuk]

Hi Sorry for the delay in replying but I have been away for a few days and have only just returned and read your post.
The box I have is identical to the one shown on the diagram from Honeywell I can only say that I must have imagined the red wire terminal but it still has one more terminal than I have wires I have green/yellow Grey blue orange and white but the box has a terminal for a brown wire also
As I don't have a programmer I may as well get a 10 strip connector box and wire it using the diagrams from Honeywell and yourgoodself many thanks for bothering with me but I now have it clear in my mind the connections for using the programmable thermostat with a 2 way plate switch controlling my heating system in a Y control mode