C Plan

6 Jul 2008
Reaction score
United Kingdom
Have just bought a Honeywell 2 port valve (V4043H1056) to use in a 'C' plan system - the plan shows 6 wires from valve Grey, Blue, G/Yellow, Brown, White, Orange, mine has 5 wires (no White). Can anyone let me know the correct way to wire the 'C' plan using 5 wires (Grey, Blue, G/Yellow, Brown and Orange)
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You have purchased a 22mm valve. 28 has six wires. Gravity runs are 28mm.
Thanks for the reply, there is a 22mm leaking valve already in the system, I thought straight replacement, should of known nothing is simple - I think the 22mm valve will be heading E-Bay's way!!
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Cant read the part number its covered in rust, have spoken with 2 plumbing merchants and they both confirmed that the 28mm valve (V4043H1106) does have 6 wires. I will let you know tomorrow when it arrives.
The original 22mm valve had 5 wires but was wired to a home made control unit which has to be seen to be believed it has now been consigned to the bin.
The V4043H1106 is only suitable for gravity DHW, not to be confused with the normal 28mm 2 port valve, which is the same as the 22mm. Normal 2 port valves have 4 core (+earth), normal 3 port valves have 5 core (+earth). Then you get preference valves just to confuse the issue.

Just read your original post again, if you do have a C plan system, you do need the V4043H1106, and not the one you bought
where do you keep getting the info of 3 port valves have 5 wires + earth.
5 wires in total grey, blue, orange, white, earth.
Oops, sorry. I'm thinking of the older models which did have a total of 6 wires. Will try and look up what makes, just for interest.
(must pay attention!)
Right, I'm back home and back in this century.
It was of course the original Honeywell 3 port that had 6 wires, replaced in the 70s(?).
No I'm not having drug flashbacks, I've got a better excuse.
I'm cat sitting this week, this means
A. lots of time sitting in front of a computer
B. 4 sets of needles gently working deeper towards my vital organs because she doesn't like anything less than 100% attention. This does reduce my concentration.
Sorry for misleading everyone.
CAT 999
28mm valves were often used to control gravity loops to cylinder. As such they needed six wires- brown, blue, green-yellow, orange, grey and white.

Maybe i am living in a different dimension but have yet to see a 5 wire core cable on a head that carries earth wire. You can get 6 cores on a replacement Honeywell actuator that will fit 22mm valve. Been there and done it.

OP do find out which three port valve fitted to your system. Some systems were fitted with a diverter valve (HW priority) as opposed to midposition valve.
c plan 2 port valve uses white wire to feed live via orange wire to boiler on when 2 port closed. ie earth blue grey brown orange white. 6 cores. 4043h replacement powerheads have white which is made safe on s plan

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