AAON WH Series User Manual

42
Table 8 - LED Diagnostic Codes
Number
of LED
Flashes
Fault
1
High Discharge Pressure
2
Emergency Shutdown
3
Auxiliary Alarm
4
High Condensate Level Alarm
5
Low Control Voltage Alarm
6
High Control Voltage Alarm
7
Low Suction Pressure
8
Leaving Water Temperature
Alarm
9
Air Coil Low Temperature
Alarm
10
Entering Water Temperature
Alarm
Automatic Reset Alarms
The following alarms will automatically
reset themselves once the fault condition
clears.
Low Control Voltage Alarm
The low voltage alarm will activate when
the 24VAC control voltage drops to 20VAC
+/-5%. Below this voltage the onboard
normally open relays are not guaranteed to
close. The low voltage alarm will release
when the voltage rises above 22VAC +/-5%.
Once the fault is cleared the controller will
activate a random start delay. This alarm
will disable the compressor, the supply fan,
and the reversing valve.
High Control Voltage Alarm
The high voltage alarm will activate when
the 24VAC control voltage increases to
32VAC +/-5%. Any voltage higher than
this risks damaging components on the
control board. The alarm will release when
the control voltage decreases to 30VAC +/-
5%. Once the fault is cleared the controller
will activate a random start delay. This
alarm will disable the compressor, the
supply fan, and the reversing valve.
Leaving Water Temperature Alarm
To prevent freezing of the liquid heat
exchanger, the leaving water temperature
alarm will activate and turn the compressor
off if the refrigerant saturated suction
temperature during heating drops below the
freeze protection temperature setpoints in
Table 9 - Glycol Percentage Setpoints, based
on the glycol percentage that is input into
the controller. The alarm will deactivate
(allowing the compressor to run again) after
ten minutes have expired and the refrigerant
saturated suction temperature rises 5°F
above the freeze protection temperature. If
the alarm is activated again within two
hours, the refrigerant saturated suction
temperature must rise 5°F above the freeze
protection temperature and the unit power
must be cycled off and on or the compressor
activation call from the thermostat must be
removed and then restarted.
The glycol percentage DIP switch “SW1” is
used to set the glycol percentage that is used
in the system for freeze protection. This
switch is located in the center of the control
board. The freeze protection setpoints
change based on the glycol percentage that
is input to the controller. It is critical that
this setting matches the actual glycol
percentage used in the system to prevent
damage caused from freezing. Inputting a
glycol percentage that is higher than actually
used in the system can cause extensive
damage from freezing.

AAON WH Series Specifications

General

Brand	AAON
Model	WH Series
Category	Heat Pump
Language	English