Description

The Intermatic 156T1978A tripper set contains one on tripper and one off tripper for T100 Series time switches and mechanisms.

What the trippers do

A mechanical time clock is just a motor turning a dial. The trippers are the small clamps you slide around that dial, and they are what physically throws the switch as the dial rotates past them. The on tripper starts the load, the off tripper stops it. Move them and you move the schedule.

Why they get replaced

Trippers live outdoors in a timer enclosure for years. They go brittle, the clamping screw strips, or a tab breaks off. When that happens the timer looks fine and the motor still turns, but the pump either never starts or never stops.

Running more than one cycle

One set gives one on and off cycle per day. If you want the pump to run in the morning and again in the evening, fit a second set of trippers for the second window.