Specifications

164015-YIM-A-0905
60 Unitary Products Group
Charging The Unit
All ZH units use Thermal Expansion Devices. Charge the unit to
10° subcooling.
Troubleshooting
Predator
®
Flash Codes
Various flash codes are utilized by the unit control board (UCB)
to aid troubleshooting. Flash codes are distinguished by the
short on and off cycle used (approximately 200ms on and
200ms off). To show normal operation, the control board
flashes a 1 second on, 1 second off “heartbeat” during normal
operation. This is to verify that the UCB is functioning correctly.
Do not confuse this with an error flash code. To prevent
confusion, a 1-flash, flash code is not used.
Current alarms are flashed on the UCB LED. The alarm history
can be checked by pressing and releasing the ALARMS button
on the UCB. The UCB will cycle through the last five (5) alarms,
most recent to oldest, separating each alarm flash code by
approximately 2 seconds.
In some cases, it may be necessary to “zero” the ASCD for
the compressors in order to perform troubleshooting. To
reset all ASCDs for one cycle, press and release the UCB
TEST button once.
Troubleshooting of components may require opening
the electrical control box with the power connected to
the unit. Use extreme care when working with live
circuits! Check the unit nameplate for the correct line
voltage and set the voltmeter to the correct range before
making any connections with line terminals.
When not necessary, shut off all electric power to the
unit prior to any of the following maintenance
procedures so as to prevent personal injury.
Label all wires prior to disconnection when servicing
controls. Wiring errors can cause improper and
dangerous operation which could cause injury to person
and/or damage unit components. Verify proper
operation after servicing.
Table 29: Unit Control Board Flash Codes
Flash Code Description
On Steady Control Failure - Replace Control
Heart Beat Normal Operation
1 Flash Not Applicable
2 Flashes Control waiting ASCD
1
1. These flash codes do not represent alarms.
3 Flashes HPS1 - Compressor Lock out
4 Flashes HPS2 - Compressor Lock out
5 Flashes LPS1 - Compressor Lock out
6 Flashes LPS2 - Compressor Lock out
7 Flashes FS1 - Compressor Lock out
8 Flashes FS2 - Compressor Lock out
9 Flashes
Ignition Control Locked Out/
Ignition Control Failure / Limit Switch Trip / No
Jumper Plug in Heat Section
10 Flashes
Compressors Locked Out On Low
Outdoor Air Temperature
1
11 Flashes
Compressors Locked Out Because The
Economizer Is Using Free Cooling
1
12 Flashes
Fan Overload Switch Trip - Not Applicable On
This Unit
13 Flashes Compressor Held Off Due To Low Voltage
1
14 Flashes EEPROM Storage Failure (Control Failure)
OFF No Power or Control Failure
Table 30: Ignition Control Flash Codes
Flashes Fault Conditions Check
STEADY ON Control Failure Control
HEARTBEAT Normal Operation
1 Not Applicable
2
Pressure Switch
Stuck Closed
Pressure Switch
3
Pressure Switch Failed
To Close
Venter Pressure Switch
Vent Blocked
4 Limit Switch Open
Main Limit
AUX Limit
5
Flame Present With Gas
Off First Stage Gas Valve
Energized With W1 Off
Second Stage Gas Valve
Energized With First
Stage
Gas Valve Off
Gas Valve
6 Ignition Lockout
Gas Flow
Gas Pressure
Gas Valve
Flame Sensor
STEADY OFF
No Power Or Control
Failure
24VAC or Control