24V Ac Circuit Power Monitor; Led Indicators - Robertshaw 9720 User Manual

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24V AC Circuit Power Monitor

If you experience a loss of power, this thermostat will indicate "-AC" in the time field of the LCD
display. This means that your system's 24 V AC circuit is not receiving power or is not functioning
correctly. The back-up batteries provided in this thermostat will maintain the programming during
the loss of power, however, the thermostat requires 24V AC power and a functioning system for
proper control.

LED Indicators

There are three LED indicators located on the front of your Robert Shaw thermostat. They are designed to
inform you of the following:
AUX (GREEN):
CHECK (RED):
EMER (RED):
This turns on when the auxiliary (also called back-up) heating is in
operation. This is the second (non-economy) stage of heat.
When this turns on, a malfunction has occurred somewhere in the heat
pump system. Please contact a qualified service technician as soon as
possible to check your system.
This light turns on whenever the emergency heat is manually selected
(system is in the EMER mode). While in the emergency heat mode, the
heat pump compressor is off, and the emergency heat (same as the
auxiliary heat) maintains the setpoint temperature.
OPERATION