Aprilaire 8535 - Manual (Page 9)

Operating The Aprilaire Thermostat
1. Select the mode of operation by repeatedly pressing the MODE button until the desired mode
appears on the display (“E ht” = Emergency Heat – Models 8536 and 8537 only). The heating and
cooling system may be turned off by selecting the “OFF” mode. Do not set to the “OFF” mode
during periods when freezing temperatures may occur.
• COOL: In the “COOL” mode a Snowflake “ “ icon appears on the display, which flashes
when the heat pump is running.
• HEAT: In the “HEAt” mode a Flame “ “ icon appears on the display, which flickers when the
heat pump is running.
• EMERGENCY HEAT (Models 8536 and 8537 only): In the Emergency Heat mode, “E ht” appears on
the display and only the back-up heat source (other than the heat pump) will be used to maintain
temperature. The center LED (located at the top of the thermostat) will light when the back-up
heat source is running.
• AUTO: In the “AUtO” mode, the heat pump will operate in either the “HEAt” or “COOL” mode
depending on which current setting the room temperature is closest to. Note that both the
Snowflake “ “ and Flame “ “ icons appear on the display.
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