Honeywell st699 to st9400 install

[mikegc]

Hi,

I want to replace my st699 with the 9400. The install/conversion guide looks simple enough, but what do I do with the cables that are marked not connected (ie 5 and.

I also have no wire going to 4, but it wants me to put that into 2.

Thanks
Mike

 

[mikegc]

Uploaded a picture of the current wiring

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• mikegc
• 30 Nov 2013
• 1

And link to install guide:
http://www.honeywelluk.com/Documents/Installation-Guide/pdf/835.pdf

OK, ignore the 5 & 8 question, as I just realised they are only connected together rather than into the system! But what to do about connecting 4 to 2 when it doesn't exist?

 

[denso13]

2 on the 9400 if the CH off connection. These are used depending on what zone valves/stats your system has. If you don't have an existing wire then it should be fine not connecting anything to 2 on the 9400.

 

[smiker]

I am replacing Honeywell ST699 with ST9400 but have only red and black wires on existing programmer:

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• smiker
• 11 Mar 2014
• 1

Where do they go on the new one?

Untitled

• smiker
• 11 Mar 2014
• 1

First time I've attempted anything like this!

 

[D_Hailsham]

Forget about colours; just swap the wires according to the terminal numbers.

It might be a good idea to label each wire as you disconnect it, before removing the old backplate.

ST699 -- ST9400
L --------------- L
N --------------- N
3 --------------- 4
4 --------------- 2 (There is not normally a wire here)
6 --------------- 3
7 --------------- 1

The wires linking L, 5 and 8 on the ST699 should be discarded.

TURN THE POWER OFF BEFORE DOING THE JOB.

 

[smiker]

Thank you so much! When you say the wires should be disgarded do you mean just taped up and left to hang?

 

[smiker]

Ignore me - have worked it out and have success!

 

[D_Hailsham]

When you say the wires should be disgarded do you mean just taped up and left to hang?

I said discarded (thrown away)!

There are 2 wires in the L terminal on the ST699, so should I connect both those wires to the L terminal on the ST9400?

Throw away the link wire to 5/8 and connect any remaining wires to L.

There are no wires in terminals 7 and 4 on the ST699, so I'm assuming that means that nothing will be connected to terminals 2 and 4 on the ST9400?

No, there will be nothing in 1 and 2 on the ST9400. (Look at my conversion list.)

If my assumptions are correct that will leave me with
L - 2 wires provided one is not linked to 5 or 8
N - 1 wire
1 - no wire
2 - no wire
3 - 1 wire
4 - 1 wire

Correct.

3 discarded wires (as there are also 2 in terminal 5)

There should be only 2 wires to throw away:
Link from L to 5
Link from 5 to 8.