Sangamo Q557.2 24-Hour Time Switch - 2 On/Off Cycles with Day Omit

The Sangamo Q557.2 is a 24-hour programmable time switch with two independent on/off cycles, a day omit dial and a manual override button. The unit controls mains circuits up to 20A, switching loads on and off at pre-set times across a 24-hour period without requiring daily reprogramming.

Designed for commercial heating, lighting, ventilation and pump control where regular switching patterns repeat daily, the Q557.2 suits applications like shop lighting schedules, office HVAC pre-heating, swimming pool filtration and underfloor heating circuits. The day omit dial allows specific days to be excluded from the programmed schedule — useful for skipping weekends or bank holidays without manual intervention.

The round dial face shows a 24-hour clock with red segment markers indicating the two programmable on periods. A quartz movement drives the clock mechanism, backed by a 100-hour battery reserve that maintains the programmed schedule through mains power interruptions without losing the set times. The manual override button provides temporary manual control without affecting the stored programme.

The unit measures 104mm wide × 83mm deep × 134mm high and mounts into a standard consumer unit enclosure or surface box. The 20A rating handles resistive loads including lighting circuits, immersion heaters and pump motors, with appropriate derating for inductive loads as per the manufacturer's guidance in the manual.

Product Specification Sheet

Product Manual

What does the day omit dial do?

The day omit dial allows you to exclude specific days of the week from the programmed switching schedule. Set the dial to omit Saturday and Sunday, for example, and the timer will not activate on weekends, resuming the normal schedule on Monday without manual reset.

How is the timer programmed?

Two red segment markers on the 24-hour dial are positioned to mark the start and end times of each on period. The unit allows two separate on/off cycles per 24-hour rotation. See the product manual for detailed programming instructions.

What happens during a power cut?

The 100-hour battery reserve maintains the clock and stored programme through mains power interruptions. The timer resumes normal operation when mains power is restored, without needing to be reprogrammed.

What load can it switch?

The Q557.2 is rated at 20A for resistive loads such as lighting circuits and immersion heaters. Inductive loads like motors and transformers require derating — consult the datasheet for specific load types and ratings.