Wiring a "Holiday" DT-7 timer to an existing DT-7

This drawing shows how to add a Holiday timer to prevent the Main timer from operating during a holiday by setting it to pin the First Man In feature. First set the time on both timers to the same day and time. If you have (for example) a Monday holiday and the Main timer is set to open at 08:00AM and close at 17:00, set the ON Timer 1 of the Holiday Timer to come on at about 07:50 Monday and OFF Timer 1 to about 17:10 Monday. This will bracket the Main timer settings and prevent it from opening even if the Main Timer is working in conjunction with a keypad that would normally trigger the first man in feature. Don't forget to remove the Timer 1 ON & Timer 1 OFF settings after returning from the holiday.