5284792-UIM-A-0317
10
Johnson Controls Unitary Products
FAULT AND STATUS CODE BEHAVIOR
Fault Code Storage
The main control stores the ten most recent fault codes for review by
the service technician. These codes are stored even when power is
removed from the control and will remain in memory until the control is
powered for 30 consecutive days or manually cleared from the control.
All codes are stored in order of occurrence and time stamped.
The control stores only one identical fault code during the same series
of events. For example, if two or more high pressure switch (HPS) faults
occur sequentially without another fault occurring in between the HPS
faults, the control only stores the HPS fault once.
In addition, the main unit control stores the following unit sensor values
when a fault and/or event occurs.
1. Suction Superheat
2. Liquid Subcooling
3. Liquid Temperature
4. Discharge Pressure
5. Suction Temperature
6. Suction Pressure
When a fault and/or event is present, the system will indicate the corre-
sponding fault and/or event text on the Outdoor Display status banner.
Fault Code Display
The system will provide fault and/or event text, using the Outdoor Dis-
play. Tables 7 & 8 describes the text behavior in further detail. The sys-
tem will display the fault and/or event text on the Outdoor Display when
CURRENT and/or STORED SYSTEM FAULT(s) are selected from the
FAULT MODE category. If multiple faults and/or events are present at
the same time, the Outdoor Display will show the most recent fault and/
or event with the highest priority. In the event that multiple faults and/or
events are populated at the same time, the Outdoor Display will indicate
the most recent system fault and/or event that is stored in memory. The
second system fault will not be displayed, but will be stored in memory.
For example see Table 4.
Status Code Display
The main control board contains 2 LED’s for status and fault display as
shown Figure 10 The control will provide a status code indicating the
state of the system using the Yellow LED as detailed in Table 5. The
Red LED indicates a system fault is present. Further details of the fault
can be found on the outdoor screen.
TABLE 3:
TEST Mode Option
TEST MODE OPTION
Menu Options
Operation
OPERATIONAL MODE (AC - HP)
Display current system configuration (AC or HP) and size stored in memory.
BYPASS ASCD TIMER
Bypass ASCD timer and initiate system operation if a call for space conditioning is present from the HX
TM
thermostat.
NOTICE
The display will continue to indicate the above fault (saved) value(s)
on the Outdoor Display with the active Fault and/or Event text, while
the fault and/or event is still present. When the fault and/or event has
cleared, the system will return to the General Display Operation.
TABLE 4:
Same Priority Fault Storage
Control
Description
Time of
Fault
Fault
Priority
Inverter Control Fault
Microelectronic Fault
10:15:00
1
Outdoor Control Fault
Inverter Control
Communications Fault
10:15:01
1
TABLE 5:
Status Code Display
Description
Required Condition
LED
Color
No power to control
No power to control
OFF
OFF
Control Failure
Control failure occurs and
can be detected.
ON
Yellow
System has 24 VAC present and the microprocessor is active.
No faults active
2s ON / 2s OFF (“Heartbeat”)
Yellow
Control normal operation – in ASCD period
No faults/events active,
compressor speed > 0, ASCD
timer not expired
0.1 sec ON / 0.1 sec OFF
Yellow
System is active and presently communicating successfully.
No faults/events active,
compressor speed > 0, ASCD
timer not expired
0.5 sec ON / 0.5 sec OFF
Yellow