Wiring a Honeywell ST9400c Programmer

12 Apr 2010
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United Kingdom
Hi All,

1st post here.....

I am currently putting central heating into my new house. There was only previously a coal fire that provided any form of heat!!

I have a 10 way wiring box to which the system boiler, cylinder stat, and room stat and 2x two port valves will eventually be connected when I get round to it.

My only real concern is that I have a Honeywell ST9400c programmer that has 6 terminals - Live / Neutral / CH on / CH off / HW on and HW off
and I have no idea what cable to use - Do i use two 3 core and earths or can I get a 6 core cable?
Can anyone with previous experience of installing a Honeywell ST9400c programmer provide any details please????

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If you fit spring return zone valves then you would not need to use the CH/HW OFF connections from your programmer.Use LN and two other wires to the wiring centre and therefore 4 core would suffice.Among other uses the OFF connections are used for motor open/motor close zone valves.I am assuming that this programmer requires no earth.
You should be using a Part P registered Electrician for a start my friend, DIY Electrical work has been outlawed - just like Gas! ;)
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Thanks for the info guys!!

Fitting a boiler and the final electrical work is well beyond my skills, let alone my qualifications. I just needed to know how to wire the programmer end as I have someone coming in to hang the boiler, do the gas and the electrical connections at the wiring centre.
You should be using a Part P registered Electrician for a start my friend, DIY Electrical work has been outlawed
No it hasn't. You can still DIY your electrics as long as you notify your LABC before you start, pay their fee and have them inspect it. A lot of work (generally excluding kitchens, bathrooms and outdoors) isn't notifiable anyway.

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