507607-03
Issue 1827
Page 14 of 23
Seven-Segment Alert and System Status
Codes
Alert codes are displayed using the seven segment display
located on the outdoor control.
NOTE:
System fault and lockout alarm code displays takes
precedence over system status (cooling, heating stages or
defrost/dehumidification).
The seven segment will display an abnormal condition
(error code) when detected in the system. A list of the
Re-Setting Alert Codes
Alert codes can be reset manually or automatically:
Manual Reset
Manual reset can be achieved by one of the following
methods:
• Disconnecting R wire from the main control’s R
terminal.
• Turning the indoor unit off and back on again. After
power up all existing codes will display 60 seconds
and then clear.
Automatic Reset
After an alert is detected, the main control continues to
monitor the unit’s system and compressor operations.
When/if conditions return to normal, the alert code is turned
off automatically.
Operation
Outdoor unit and indoor blower cycle on demand from
the room thermostat. When the thermostat blower switch
is moved to the ON position, the indoor blower operates
continuously.
Filter Drier
The unit is equipped with a large capacity bi-flow filter
which keeps the system clean and dry. If replacement is
necessary, replace with one of similar design and capacity.
The replacement filter drier must be suitable for use with
R410A refrigerant.
Crankcase Heater
If unit is equipped with a crankcase heater, it should
be energized 24 hours before unit start-up to prevent
compressor damage as a result of slugging.
Emergency Heat Function (Room Thermostat)
An emergency heat function is designed into some room
thermostats. This feature is applicable when isolation of
outdoor unit is required or when auxiliary electric heat is
staged by outdoor thermostats. When the room thermostat
is placed in the emergency heat position, the outdoor unit
control circuit is isolated from power and the field-supplied
relays bypass the outdoor thermostats. An amber indicating
light simultaneously comes on to remind the homeowner
that the unit is operating in the emergency heat mode.
Emergency heat is usually used during an outdoor
shutdown, but it should also be used following a power
outage if power has been off for over an hour and the
outdoor temperature is below 50°F. System should be left
in the emergency heat mode at least 6 hours to allow the
crankcase heater sufficient time to prevent compressor
slugging.
Outdoor unit and indoor blower cycle on demand from
the room thermostat. When the thermostat blower switch
is moved to the ON position, the indoor blower operates
continuously.
Time Delay
The timed-off delay is 5 minutes long. The delay helps
to protect the compressor from short cycling in case the
power to the unit is interrupted or a pressure switch opens.
Pressure Switch Circuit
The control includes two pressure switch circuits. A high
pressure switch is connected to the board’s HI-PS terminals
(Figure 14). The low pressure, or loss-of-charge pressure
switch, is connected to the LO-PS terminals.
During a single demand cycle, the defrost control will lock
out the unit after the fifth time that the circuit is interrupted
by and pressure switch wired to the control board. In
addition, the diagnostic LEDs will indicate a locked-out
pressure switch after the fifth occurrence of an open
pressure switch.
The unit will remain locked out until power to the board
is interrupted, then re-established, or until the error is
cleaned.
NOTE:
The control board ignores input from the low
pressure switch terminals as follows:
• During the TEST mode
• During the 90 seconds start-up period
Fan Cycling (J3)
Fan cycling routine when activated will cycle the fan ON
(Figure 14) for five minutes if the outdoor ambient air
temperature is between 15ºF and 35ºF and the compressor
has been OFF for 25 to 30 minutes. This option is to help
reduce the potential for ice build up on the orifice ring
during system OFF cycles that are greater than 25 to 30
minutes.
