Honeywell THR850SWE TM1 and TM2
The Honeywell Home THR850SWE TM1 is a 7-day capable timer that has many of the great features people now expect from a digital controller. The TM1 is a single channel. If you want two channels there is the TM2. These two models are the close to the same other than the difference in the amount of channels. The design is very basic, and the interface is very easy to program.
Main features include: 1 day, 5/2 or 7-day programming with up to 3 on/off schedules each day, holiday mode, extra hour [up to 3 hours], override, 12/24 hours clock, auto summer / winter clock adjustment, copy program option, Line of text (LoT technology – which is basically helpful hints and tips) and permanent memory saving of presets, even with a mains outage.
The back-light is adjustable to suit the users needs. The options for this are: constantly on, completely off always, and on for a few seconds when a button is pressed.
The back-plate is compatible with many older models, including the ST7100. Should be a fairly easy swap for many systems. Other older Honeywell models known to have compatibility that have wiring documentation relating to the THR850S are the ST6100A, ST9400, ST6200, ST6300, ST699, ST799, ST7100, ST6100C, ST9100A, ST9100C and ST7000B.
It’s also a good replacement for the ST9100C (TM1) and ST9400C (TM2). As a side note: wire fitting / feeding is back entry of the unit, not lower entry.
There are no major problems to report with either of these models. User reviews and reliability scores are, overall, very good.
If you’re looking for the PDF manual for both of these models, they can be downloaded from the official Honeywell Home website here for the TM1 the (also referred to as the Resido TM1), and here for the TM2. Both manuals include wiring diagrams and mounting information.
