White Rodgers 90 SERIES 1F95-391 Operating Instructions Manual page 34

FAQs
(cont.)
16. What is the thermostat
Click Test?
17. What do AUX,
EMER, and MALF
indicators mean on a
heat pump thermostat?
1F95-391
You can raise and lower the temperature a few degrees above and below the room tempera-
ture and each time expect to hear the thermostat click on and off within a few seconds. If it
clicks, it is operating properly.
Aux. = Auxiliary Heat or the second stage of heat in the Heat mode. This is energized
when the Heat Pump is not keeping up with the thermostat setting. It is normal operation
with most pumps for the thermostat to call for auxiliary heat.
Emer. = Emergency Heat. When switched to Emergency the thermostat bypasses the pump
and uses the back-up heat. This is useful if the pump is not operating correctly or if the
temperature outside is so cold that the pump is not economical to run.
Malf. = Malfunction. Malfunction indicates the heat pump system is sending a signal to the
Malfunction Light on the thermostat terminal marked "L". It does not indicate a malfunc-
tion in the thermostat. The manufacturer of the Heat Pump system can determine the likely
cause of malfunction indication on the thermostat.
In many heat pump systems Emergency and Auxiliary heat are the same source. If you
switch the thermostat to Emergency it will bypass the heat pump and bring on the back-up
heat. If you leave the thermostat in the Heat mode it will call for Auxiliary when the pump
is not keeping up with your setpoint temperature. Emergency is energized on a call for heat
in the Emergency heat mode.
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