Sangamo S255.2 24 Hour 4-Pin Zone Time Switch - 2 On/Off Cycles 20A

The Sangamo S255.2 is a 24-hour programmable zone time switch rated at 20A, designed to control heating zones, immersion heaters, lighting circuits and other timed loads through two on/off cycles per day. The unit uses a 4-pin mechanical dial with adjustable segments to set when power is supplied to the connected load, and includes a day omit dial that allows the 'ON' operation to be skipped on selected days without reprogramming the timer.

Designed for installation in consumer units or electrical enclosures with DIN rail mounting, the S255.2 suits both residential and light commercial applications where scheduled control of electrical loads is required. The mechanical dial rotates once per 24-hour period, with pins pushed in or out to determine when the circuit switches on or off. A manual override button on the front of the unit provides temporary manual control without affecting the programmed schedule.

The round dial face measures 104mm wide by 134mm high by 83mm deep overall, with clear numeric markings from 1 to 24 representing each hour of the day. The unit operates without a battery reserve, meaning it will lose its time reference if mains power is interrupted and will need the dial repositioning to the correct time after a power cut. The 20A rating handles loads up to 4,600W on 230V mains, covering most domestic heating zone valves, immersion heaters and lighting loads.

Product Specification Sheet

Product Manual

How many on/off cycles can be programmed per day?

The S255.2 provides two on/off cycles per 24-hour period. Each cycle is set by positioning the 4 pins on the dial to mark the start and end of the 'ON' period. For more complex schedules requiring more than two cycles per day, a different timer model with additional programming capability would be needed.

What happens if there's a power cut?

The timer has no battery reserve, so it will stop during a power cut and lose its time reference. When power is restored, the dial will need to be manually rotated to align with the current time of day. The pin positions remain in place, so the programmed schedule itself is not lost.

Can the timer skip certain days?

Yes. The day omit dial allows the 'ON' operation to be skipped on selected days without removing the pins or reprogramming the timer. This is useful for skipping weekends or public holidays where heating or lighting may not be needed.

What loads can it control?

The 20A rating handles loads up to 4,600W on 230V mains, including heating zone motorised valves, immersion heaters, lighting circuits and commercial equipment. The timer is not suitable for highly inductive loads or motors above 1HP without additional contactor control.