Aprilaire 8556 User Manual
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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.
110-791B 7/12/01 8:58 AM Page 23