Yet another Honeywell ST9100S thread

9 Sep 2021
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United Kingdom
Hi All

I have a honeywell ST9100 and a HC60NG. which I am going to change to a Dayton wiser setup.

I popped the lid off the st9100s and understand all I need to move is the wire from the 4 to the 3 to make it work so that bit is not a problem.

I want to completely remove the HC60NG.

Understand the Live and neutral is just the case of removing. and I am guessing that just feeds back to the switched spur, (all my wiring seems to be in the wall)

And link 2 of the other wires to give it a constant link?.

I found a diagram that explains the ST9100s and the HC60NG but not working with each other.

Thank you in advance for the help.
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From what I can gather, the st9100s is a timer and the HC60NG is a receiver for a wireless handheld unit, which will be a room thermostat. You can link the 2 wires to bypass it, if you want to remove it altogether then the wiring needs to be traced so you know where it links them together.
thanks for the quick reply, Yes that's correct.

Lucky for me the units and switch are very close to each other and there is no other junction box that I can find. (might of got the model unit of the top one slightly wrong) as under the cover says R6660D

Ahh that’s a little better, thank you. So it appears the wiring (could be wrong) might just come from the programmer underneath, in which case it should be really easy to disconnect the top one altogether.
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I was going to test it but the battery is flat in the multimeter. So that's a tomorrow job

My guess is 1 of them wires goes to the boiler and the other goes to the below unit. so I can join A and B shove it in the wall and forget about it.

Or do it the right way, find out which cable is the link between the bottom and top unit and just remove it. and move the other cable to the controller.

Pull back the Neutral and live to the switch. from the WiFi receiver and remove it.

And put a earth into the controller that it seems to have never had from being installed... Even though you can see one in the wall :).
And put a earth into the controller that it seems to have never had from being installed... Even though you can see one in the wall
doesnt use an Earth, and never assume a green and yellow wire in a heating system is an earth
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Small update, Call for heat? wire was just looped to the above unit from the controller as I thought.

Neutral is just looped from the above unit as well.

Live that's another story awaiting an amazon delivery of bits just to be safe before I start digging deeper.

Drayton wiser smart unit is connected and working.

Thanks for the help all.
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