Replace single channel programmer with two channel

[jdub]

Hi,

I have what looks like a conventional Y-plan system, except that the very antique mechanical timer only does on or off. I think the system is arranged so that hot water gets priority over the heating.

How difficult would it be to change the wiring to use a 2-channel programmer to get independent control of water and heating?

Is there a standard Y-plan arrangement with a single channel programmer? Is there a wiring diagram for this?

Thanks in advance for any help, apologies if this has been covered before, I did a search without finding anything.

John

 

[doitall]

Probably need to alter the pipework as well.

 

[Boilerman2]

If yours is a hot water priorty system it is the old Honeywell "W" Plan, and what actually looks like a 3 port mid pos valve is really a "Diverter" valve
you will probalby need to replace this with a Y plan Mid pos valve
obvioulsy there are some wiring mods to do as well!!

 

[jdub]

If yours is a hot water priorty system it is the old Honeywell "W" Plan, and what actually looks like a 3 port mid pos valve is really a "Diverter" valve
you will probalby need to replace this with a Y plan Mid pos valve
obvioulsy there are some wiring mods to do as well!!

I've had a look at the W plan info and judging from my valve wiring it looks like a mid pos valve. Ignoring the earth and neutral connections, it has white, orange and grey wires which are all connected (orange and grey to the cylinder stat, the orange also has a red connected which I guess goes to boiler + pump)

I've got some paperwork somewhere that I got from the previous owner that might shed some light but I don't think it had a wiring diagram