S Plan Plus extra zone valve wiring.

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Wired my S plan plus but not 100% on the extra zone valve and thermotsat wiring.
Have three valves, HW, Upstairs and Downstairs CH.
Got 2 valves wired as per Honeywell diagram (all Honeywell parts).
The third valve thermostat has a three core and earth wire. Presumably one of the wires on the thermostat will connect to the brown wire on the zone valve (live) which will need to be separate from the other heating valve so it can be turned on/off independantly. what about the other two wires, will they be able to share the wires on the other heating zone valve?

I have a daigram for S plan pls for Sundial but it is for a wireless thermostat and slightly different i.e just two wires.

Thanks :confused:
 
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Here is the S Plan Plus wiring diagram:

View media item 12265
The three terminals of the thermostat will be Live, Neutral and Switched Live (and possibly earth); They should be labelled.


Brown wire of the third valve connects to the thermostat Switched Live terminal.

Blue wire of third valve connects to the neutral terminal on the junction box (usually terminal 2)

Grey wire connects to the Live terminal on the junction box (usually terminal 1)

Orange wire connects to same terminal as the orange from the other two valves.

So all valve blue wires go to one terminal
All valve grey wires go to the same terminal
All valve orange wires go to the same terminal

The brown wire from each valve must go to three separate terminals.

If your pumps has to be wired directly to the boiler, connect it to terminal nine (not 10 as shown) and connect 9 to the boiler's pump live terminal.
 
Hi

I've got the system all wired up apart from the Honeywell ST9400c programmer. Am I right in thinking that I just need to connect the L, N and Earth up to my 10 block wiring centre with some 2.5 T & E?

There are some more terminals maybe 4 or 5 from memory, does anyone have a wiring diagram for this controller or just an explanation of what to do to link it to the valves?

:confused:
 
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I don't remember the terminals being labeled e.g Hot water or CH?
Maybe I have missed something?
 
I have the S plan plus wired up all working apart from the CH off. I have not connected this on the ST9400c programmer as it was not on the diagram.

I have

Terminal 1 HW off going to 7 on junction box
Terminal 3 HW ON going to 6 on the JB
Terminal 4 CH ON going to terminal 4

Terminal 2 I think is CH OFF, I do not have this connected?
The valves will turn the water off if the thermostat is down but I can use the programmer to turn the CH off or presumably use the timer to switch the heating off??

Any ideas gratefuly appreciated.
 
Terminal 2/CH OFF is only used if you have motor on/ motor off motorized valves. You do not have this type of valve, so the terminal is not used.
 
So how does the programmer switch off the CH?
If I have it set to Auto the thermostats will turn heating on and off but what if I use a timer?

Really appreciate the help..
 
So how does the programmer switch off the CH?
The motorized valve is held in the closed position by a spring. When the heating turns on, voltage is applied to the motor, via the programmer and the room thermostat, which opens the valve. This closes a switch in the valve which applies voltage to the boiler to light it. When the voltage is removed from the motor, the spring will close the valve and the switch in the valve will open, removing the voltage from the boiler, which goes out.

If I have it set to Auto the thermostats will turn heating on and off but what if I use a timer?
When the programmer is set to Auto, a switch in the programmer turns the voltage to the room thermostat on or off at the times programmed. If no voltage is getting to the room stat, then it can't get to the valve, so the boiler stays off.

What do you mean by if I use a timer?
 
Ah Ok Cheers.
I meant just adding ON and OFF times using the programmer, I didn't explain very clearly, sorry about that.

When I switch the programmer to heating off, it does not go off so something must be wrong somewhere. I have two thermostats, only one wired in on the downstairs and this turns on and off with the thermostat so maybe there is an issue with upstairs thermostat wiring (does not have a thermostat attached at present but is made safe).

I am assuming when I set the programmer to heating off, somehow a signal is getting to the valve and thermostat to stay off ? I can see how the thermostat and valves can communicate with the programmer but not vice versa?
 
I meant just adding ON and OFF times using the programmer,
Sorry, but I'm still unclear. What do you mean by this?

When I switch the programmer to heating off, it does not go off so something must be wrong somewhere. I have two thermostats, only one wired in on the downstairs and this turns on and off with the thermostat so maybe there is an issue with upstairs thermostat wiring (does not have a thermostat attached at present but is made safe).
Presumably you have one programmer and use the CH side to control both heating circuits. If so, have you wired up as shown in the diagram I posted earlier?

What you have sounds like back feed - voltage going the wrong way round the circuit.

Disconnect the wires for the upstairs thermostat at the junction box

If the problem goes away, there is something wrong with the wiring for the upstairs circuit.

If the problem remains, disconnect the grey wire of the upstairs valve.

If the problem goes away, the upstairs valve is faulty - internal switch is permanently closed.

If the problem remains then it must be in the downstairs circuit.

Disconnect grey wire of downstairs valve.

If problem remains, the downstairs valve has a sticking internal switch.

I am assuming when I set the programmer to heating off, somehow a signal is getting to the valve and thermostat to stay off ? I can see how the thermostat and valves can communicate with the programmer but not vice versa?
It's the other way round! A voltage is applied by the programmer to thermostat, which sends it to valve. If the programmer is off, no voltage gets to the thermostat or the valve and the boiler stays off.
 
I meant just adding ON and OFF times using the programmer,

Sorry, but I'm still unclear. What do you mean by this?

7:00am CH OF
8:00am CH OFF

16:45 CH ON
18:00 CH OFF

Using the digital programmer.

Presumably you have one programmer and use the CH side to control both heating circuits. If so, have you wired up as shown in the diagram I posted earlier?

Yes and Yes.

I haven't removed the upstairs thermostat to test yet but it looked like
that number 7 on the wiring box had my upstairs thermostat switched live wired to it and also brown wire from the second valve
Terminal 1 HW off going to 7 on junction box ??

I did not think that the Hot water OFF would have anything to do with this valve?
 
I haven't removed the upstairs thermostat to test yet but it looked like that number 7 on the wiring box had my upstairs thermostat switched live wired to it and also brown wire from the second valve.
Terminal 1 HW off going to 7 on junction box ??

I did not think that the Hot water OFF would have anything to do with this valve?
HW OFF is not used with this type of valve, so there should not be a wire from HW OFF to terminal 7.

Just been looking again at the diagram I posted and realized that it could be confusing as it uses a programmable stat as well as a non-programmable one. Presumably you have two non-programmable.

In which case wire as follows:

CH ON to terminal 6.
Both thermostat Live to Terminal 6
Both thermostat Neutrals to Terminal 2 (if they have Neutral connections)
Both heating valve Grey wires to terminal 1
Both heating valve Orange wires to Terminal 10
Both heating valve Blue wires to Terminal 2
Ground Floor Thermostat Switched Live to Terminal 5
Ground Floor valve Brown to Terminal 5
First Floor Thermostat Switched Live to Terminal 7
First Floor valve Brown to Terminal 7
HW ON to terminal 6
HW stat common to Terminal 6
HW stat Call to terminal 8
HW valve Grey to terminal 1
HW valve Blue to terminal 2
HW valve Orange to terminal 10
HW valve Brown to terminal 8
 

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