Upgrade to Honeywell T6R-HW smart thermostat

11 Dec 2010
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United Kingdom
Hi guys,

I've tried to upgrade my current CH programmer from a Randall 4033 to a Honeywell T6R-HW.

I have an Ideal Classic HE15 boiler, hot water tank upstairs in the spare bedroom and header tanks in the loft (hopefully that narrows down the type of CH system I have).

The problem i have is how i switch the wiring from the 4033 to the new T6R-HW.

Below is a picture of my current wiring setup and my interpretation of how this should be wired into the smart thermo.

Am i right that;

1 - no longer required
2 - A
3 - not used
4 - E
5 - not used
6 - the red and green now go into the first L feed
7 - N
8 - Earth again (block 1 on the smart thermo)

Appreciate any input



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I've just tried wiring it as follows and still no joy :(

1 - no longer required
2 - B
3 - not used
4 - E
5 - not used
6 - L
7 - N
8 - Earth
Do you have two two-port zone valves, or one three-port mid-position valve? Post a photo of the pipework by your hot water cylinder if you're unsure
Hi muggles,

Yes i have two two-port valves just to the left of the boiler. At the minute i've still got the original thermostat plugged in but it's cranked up to 30 (from what i've read that should stop it being a problem until i've got the T6R working, right?

It all lights up as you'd expect, connects to the receiver, the heating and water buttons on the box light up when pressed but they don't seem to send any signal to the boiler as it doesn't react to them.

EDIT* - I've also not bridged the A + D connections to the Switch Live - should I?
Last edited:
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Update - I think I've got it working (going to check again when I get home from work). I've used the Switched Live to A + D and the original CH & HW wires to B & E. L N and E are a straight swap.

Now when I turn the heating on via the Honeywell app, I see the valve next to the boiler switch between A - B so I think that's all good.

Should turning the water on also make a valve move?

I'm left with 2 problems (I had these before installing the Honeywell T6R so I know it's not related);

The boiler seems to randomly fire on/off even when the programmer is set to off. The rads don't seem to heat up during these shortish cycles.

Randomly when the boiler is on it'll start making a very loud buzzing noise, sometimes for 5 seconds, sometimes for up to 30 seconds. What could this be?

Thanks again for your time.

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