The TotalHome TTH2CT 2 channel central heating programmer is a straight swap for the Honeywell ST9400C 7 day programmer. It is made and supported by Resideo: TotalHome is a Resideo brand, Resideo is the company behind Honeywell Home and was Honeywell's home heating business until 2018, and the programmer is labelled From Resideo on the back. It controls your central heating and stored hot water as two separate channels, each with up to three on and off periods a day.
Fitting: unclip the old ST9400C from its wall bracket and clip this programmer onto the same wired backplate, so the wiring stays exactly as it is. It can also replace older Honeywell ST699, ST799, ST7100, ST6200, ST6300 and ST6400 programmers with a simple wiring change at the backplate, carried out by a competent person.
Check your system: this is a wired 230V mains programmer for heating systems with a hot water cylinder, including Y plan, S plan, C plan and W plan layouts. It is not wireless and not an app or Wi-Fi thermostat. A combi boiler with no hot water cylinder only needs a single channel timer.
Programming: each day of the week can be set on its own, or use the copy day button to repeat a day across the week. Choose 7 day, 5/2 day or 1 day programming and 2 or 3 periods a day. It arrives with an energy saving schedule already set, plus comfort and economy presets.
Everyday use: the mode buttons switch each channel between Continuous, Once, Auto and Off. Extra Hour adds 1 to 3 hours, Override switches a channel on or off until the next programmed time, and Holiday mode turns heating and hot water off for up to 99 days. The clock changes automatically in spring and autumn and your settings are kept if the power fails.
Display: large backlit screen with text prompts, 12 or 24 hour time and a green light for each channel.
In the box: 7 day 2 channel programmer, wall bracket and user and installation guide.