Programmer wiring.

[D_Hailsham]

Thanks Whitespirit66, the grey wire from the motorised valve links to the "earth" wire to the tank stat. There is no other wire taken from that connection.

Am I doomed?

Hopefully not.

The earth wire from the tank stat to the valve grey is being used as a control wire, not an earth. It's the cheap and lazy way of having three connections without buying the correct cable.

All you now need is a wire from the programmer terminal 1 to the grey wire (This is in addition to the wire from the tank stat.)

You said that terminal 1 is already connected to the L terminal. It shouldn't be there It is an obvious get-around due a shortage of cores in the cable from the programmer to the junction box. It will be the cause of your problem.

The only way you will solve it is to run a new cable with the correct number of cores.

 

[Rocketmen]

Thanks guys.

It appears that I will have to live with HW and CH on at the same time. The missing cable can't be retro fitted due to the cables running along solid walls that were long since tiled over!

Cheers for all your help.

 

[D_Hailsham]

Just a thought.

Which model Landis and Gyr programmer are you replacing?

 

[simond]

If a flex has been used, with certain caveats, the green/yell can be used as a phase conductor. The most important of these is that each end is brown sleeved.

If it is a 'flat twin and earth' you can't use the CPC (bare earth).

 

[Rocketmen]

Hi, the old programmer was a Landis and Gyr type RWB2.

 

[matt1e]

Thanks guys.

It appears that I will have to live with HW and CH on at the same time. The missing cable can't be retro fitted due to the cables running along solid walls that were long since tiled over!

Cheers for all your help.

have you got a wiring centre adjacent to the valve?
If there is a permanent live in there fed from the central heating circuit then you don't need to run a core back to the programmer, you can fit a local changeover relay to give you a hotwater off signal
let me know if you need a diagram

Matt

 

[Rocketmen]

Yes Matt, I have 5 cables running into a junction box next to the valve. These are for the tank stat, valve, pump and 2 flat grey cables which disappear into the wall in the general direction of the boiler/programmer/room stat. The 2 flat cables are both 3 core, one of which has a fitted sheath which looks like it is being used as an earth. The other grey cable has 3 insulated wires, including a yellow which is connected to the blue on the tank stat. My meter failed to find a permanent live cable.

Thanks

 

[matt1e]

Yes Matt, I have 5 cables running into a junction box next to the valve. These are for the tank stat, valve, pump and 2 flat grey cables which disappear into the wall in the general direction of the boiler/programmer/room stat. The 2 flat cables are both 3 core, one of which has a fitted sheath which looks like it is being used as an earth. The other grey cable has 3 insulated wires, including a yellow which is connected to the blue on the tank stat. My meter failed to find a permanent live cable.

Thanks

then you may have enough cores
and if you haven't you may still have other options
a picture of the programmer and wiring centre showing the connections would be useful

Matt

 

[D_Hailsham]

a picture of the programmer and wiring centre showing the connections would be useful

Seconded.

The link between L and T1 is unnecessary; all it does is make T1 permanently live. But as there is nothing else connected to T1, it has absolutely no effect.