On 27/11/2020 18:00, Peter Burke wrote:
Caecilius wrote in
:


My plan is to put this temperature controller between the timeclock
and the heater, and set the heater thermostat to something like 25C as
a fail-safe.

Has anyone found or built something like this? I'm sure I can't be
the only person who want a constant overnight bedroom temperature
without running the main house heating.

In a similar application I found my 2kw convectors had 2 paralleled
elements and disconnected one to make them 1kW only and less agressive in
their heat output.

All the 2 and 3KW heaters that I have ever seen have a switch that
allows it to function as a 1KW , 2KW or 3KW heater. I have three
and all have this switch, including the cheapo £15 2KW job from a
supermarket.

For control, honeywell have been forcing P+I control and multiple switching
cycles per hour on us in their room stats for years (wearing out over
cycled zone controls in the process).

Their programmable stats (eliminating the time switch) are a bit overpriced
but this one has all the P+I, default 6 cycles per hour (programmable up to
12 if desired) and is 8A rated (selectable prog option) so will direct
switch. The mag assisted batt powered internal relay should be quiet
enough.

https://www.screwfix.com/p/honeywell-home-dt90e/41365

Instructions downloadable from the spec tab of that page for a preview.

Could save a bit of faff in rolling your own.