110-791B 7/12/01 8:58 AM Page 23

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.

If the thermostat does not respond when a button is pushed it may be because the keypad has been

locked. A Lock icon “ “ will appear when a button other than OUTDOOR is pushed if the keypad

has been locked.

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Aprilaire 8556 owner manual 110-791B 7/12/01 858 AM