Armstrong Air 4SCU 16LS Series, Инструкция по установке и обслуживанию

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506859-01 Issue 1236 Page 20 of 32
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(See Figure 16). 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 an
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
(see 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.
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 codes are
shown in Table 9.
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 code 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
Seven-Segment Alert and
System Status Codes