Aprilaire 8553 - Manual (Page 23)

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Day, and Evening events. During the Night event, the fan will automatically revert to cycling on
and off with the heating and cooling equipment.
No. 3 – 4 Minute / 2 Minute Minimum Equipment On/Off Times. This switch is factory preset at
2 minutes. This switch provides short cycle protection for the furnace/air conditioner. If you feel
that the furnace/air conditioner turns on and off too many times per hour, ask your contractor
about changing the switch to a 4 minute minimum on time. Keep in mind, however, that this may
increase the overall temperature variation in the house due to longer run and off times. Do not
change the position of the switch without first consulting with your contractor.
No. 4 – Keypad Lock. If tampering with the thermostat is expected and unwanted, the keypad can be
locked by moving this switch from the factory-preset OFF position to ON. This should not be done
until all programming is finalized. In the locked position only the following functions can be done:
• The outdoor temperature button will display the outdoor temperature.
• The DECREASE button or INCREASE button will temporarily change the set point
a maximum of ±6°F (±3°C) for a period of 3 hours, before the thermostat
automatically returns to the original program.
110-790B 7/11/01 3:11 PM Page 23