The Honeywell ST9400S is a 1-day, 2-channel programmer designed to control heating and hot water zones independently. It features a Service Interval Timer that can be configured to provide a message or restrict action when an annual system service is due. The programmer includes a Line of Text (LoT™) display that provides clear, plain English instructions for all operations. It allows for up to 3 events per day, automatically adjusts for summer and winter time changes, and has a single pole, double throw (SPST) relay. The power supply is 230V AC 50Hz with a power consumption of 10W. The operating temperature range is 0 to 40°C, and it conforms to EN60730-2-7. It also offers temporary or permanent override facilities and a large backlit display. This timer has holes suitable for single switch boxes and provision for surface wiring, offering flexibility in installation. It includes an advanced tenant notification period and optional configuration for behavior once the service interval has expired. The LoT display can also show a telephone number to simplify arranging gas services.