Honeywell T40 replacement stat suggestions

[CountryFan]

Want a new stat as I know it does not always switch on when it gets cold, until its really cold even if I turn it up a bit, so new one needed and I read that a digital stat is more accurate and efficient than this T40

It’s not working as per the design of the thermostat. The green/yellow which should only really be used for cpc/earth isn’t insulated all the way through the cable so could be/cause a problem.

You could go for a 2 wire mechanical thermostat, a 2 wire battery operated thermostat, both of which would be better using the brown and blue wires as live and switched live and alter the other end. Your other option is to go for a wireless thermostat, but would recommend decommissioning the existing one.

Failing that you could run a new cable with enough cores to the existing thermostat or any other suitable thermostat

 

[Rodders53]

Thanks for info, was not aware of the T3 terminal connection being switched live, will need to rewire.

Can you suggest any Honeywell stat as replacement?

Depends on how you plan to rectify the existing wiring. If you go Live, Switched Live and earth ... the a battery operated 2-wire would maybe suit?

I've replaced some old Sunvic digital stats with the Honeywell/Resideo DT4 https://www.screwfix.com/p/honeywell-home-dt4-1-channel-wired-room-thermostat/633JM but have no idea how well they work yet as it's not been that cold. Downside is room temp display needs a button press. Upside is a claimed 3 year 2xAA battery life.
You may need to tweak the Installer Menu from the defaults to suit the installation.

 

[ericmark]

Hertz (Hz) - 868.6 MHz. Receiver Included. Thermostat Voltage - 230 V AC V. Mains-Powered with Battery Backup.

Oh dear, Screwfix have got it wrong again, dad! The one shown is the DT4, the description seems to be for the DT4R, these are very different thermostats. They also have the DT4R wrong, it says Receiver Power Source Battery-Powered.

As far as I am aware, the only wireless thermostat where the receiver is battery powered is the Nest-e.

The DT4 has been made for many years, however it is not the same thermostat, it has been upgraded a few times over the years.

As far as I can make out, it is not programmable in a meaningful way? Today we tend to go for three temperatures, over-night (16°C), day time (18°C) and evening (20°C) so one on a very cold night heating comes on without need for a frost stat, and once one sits down one wants it a little warmer, however cheap as these are the instructions need to be kept near, as not very intuitive I found, even if the thermostat its self is good.

As to the best thermostat depends on what you want. My first and second house only needed a very simple device, no linked TRV heads etc, but mothers house and this house need digital TRV heads, so need some feed back.