5326602-XIM-B-1019
54
Johnson Controls Ducted Systems
Charging The Unit
All ZF units use Thermal Expansion Devices. Charge the unit to
nameplate charge or 10° subcooling.
Figure 32: Unit Control Board
Table 35: 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
W1
W2
Y1
G
Y2
OCC
C
SD-24
THERMOSTAT
WIRED HERE
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R
X
