Selecting Auto Changeover - Robertshaw 9720 User Manual

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Selecting Auto Changeover

You may wish to set your thermostat so it will automatically choose
between the HEAT or COOL programs for proper temperature control.
This program feature is referred to as the AUTO (Auto Changeover)
mode of system operation.
While in AUTO mode, the thermostat will constantly monitor the room
temperature to determine whether to run the HEAT or COOL program to
maintain comfort. To operate properly, the thermostat requires a "dead
band" setting to eliminate program conflicts. The standard "dead band"
setting is 3˚ between the highest HEAT temperature setting and the
lowest COOL temperature setting for a given setpoint period. (There is
an optional 5˚ "dead band" setting available. See "CHANGING DIP
SWITCH SETTINGS.")
For example, if the highest HEAT temperature setting for the MORN
setpoint is 72˚, then the lowest COOL temperature setting for a 3˚ "dead
band" would be 75˚. The thermostat will emit a short "beep" if the user
attempts to enter a temperature setting while in the HEAT or COOL
program which would violate the established "dead band".
If you are in PROGRAM mode (PROG/MAN) and you have selected AUTO
using the SYSTEM button, the thermostat will constantly compare the
current room temperature to the current setpoint (MORN, DAY, EVE,
NIGHT) temperature settings for the HEAT and COOL programs and
choose which program is appropriate, for example:
OPERATION
75˚
Lowest cool setting
˚
74
˚
73
˚
72
Highest heat setting
3˚ Deadband
77˚
Lowest cool setting
˚
76
˚
75
˚
74
˚
73
˚
72
Highest heat setting
5˚ Deadband
(Optional)