Replacing old Honeywell programmer/ timer with smart control - looks simple but is it?

27 Dec 2022
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United Kingdom
In the 1980's I installed a conventional central heating system, 3 way diverter, one room thermostat, and a cylinder thermostat. The boiler has been replaced with a Baxi designed for these older conventional systems and the programmer is the same old Honeywell - 2 timed live supplies to the junction box, for heating and/or hot water.

What I would like to do is replace this with a smart system and the Wiser Thermostat 2 comes up on searches for this type of system.

It comes with a thermostat but research suggests that instead of connecting this thermostat in, to control the supply to the heating system, I could just connect the heating supply direct to the appropriate point in the junction box - i.e "bypass" the thermostat.

My question - is it really that simple? Also is it necessary to buy the thermostat? The cost is reasonable anyway, but It's a waste of resources.

Thank you!

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Wiser kit 2 would be required, and yes the thermostat that it comes with would need to be used in order for it to be smart. You can set the existing thermostat to maximum for the wiring if it makes it simpler for you.
All of these 'smart' efforts are the same.
A box which replaces the programmer, it's just a set of switches to turn the heating / hot water on and off.
Any existing room thermostat is removed and the wiring for it bypassed.
The new thermostat communicates wirelessly with the wired in box.
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