Filter
Top Products
166
JOHNSON CONTROLS
FORM 100.50-NOM6 (1207)
Service
Outdoor Humidity Sensor Alarm (29)
This alarm indicates the outdoor humidity sensor is
out of range. When this occurs the Unit Controller
will switch economizer operation to Dry Bulb. The
Outdoor Humidity analog input is at OH+ wire 333 of
the P6 connector and OH- wire 334 of the P6 connector.
To trouble shoot the sensor verify 24 VAC between
terminals EXC and COM of the sensor. Also verify
the VDC between the OUT and COM connection of the
sensor. If no voltage is present replace the sensor.
Return Humidity Sensor Alarm (30)
This alarm indicates the return humidity sensor is out
of range. When this occurs the Unit Controller will
switch economizer operation to Single Enthalpy. The
Return Humidity analog input is at RH+ wire 335 of
the P6 connector and OH- wire 336 of the P6 connector.
To trouble shoot the sensor verify 24 VAC between
terminals EXC and COM of the sensor. Also verify
the VDC between the OUT and COM connection of the
sensor. If no voltage is present replace the sensor.
IAQ (CO2) Sensor Alarm (31)
This alarm indicates the IAQ (CO2) sensor is out of
range. When this occurs the Unit Controller will switch
the ventilation mode from Demand to Fixed Minimum.
The IAQ sensor input is at terminal DV+ and DV-. This
device is fi eld supplied.
Time Clock Error Alarm (32)
This alarm indicates the Unit Controller Real Time
Clock is not functioning. The Unit Controller will shut
down all operation. Try recycling power to the control.
If the fault reappears replace the Unit Controller.
Space Temperature Offset Alarm (33)
This alarm is generated when the resistance in the Space
Temperature Offset circuit is greater then 20,000 ohms.
The Space Temperature Offset input is at terminals SSD
and GND of the P6 connector. Check the resistance
between these to points. If greater then 20,000 ohms
check the tightness of the connections and the wire
wiring between the Unit Controller and the space sensor.
If both are okay and the resistance is still greater then
20,000 ohms replace the space sensor reset.
CV/VAV Input Alarm (34)
This alarm indicates the resistance between terminals
CV/VAV and CV/VAV at the P7 connection is out of
range. The acceptable range is 0.0 to 20,000 ohms.
Check the resistance between the two CV/VAV terminals
and take appropriate action.
Low Voltage Alarm (35)
The Unit Controller monitors the 24 VAC input to the
control. The input has two thresholds. The voltage
must be above 19.2 VAC or the control will not turn on
a contactor. If the voltage is not above this value it will
not turn on the contactor and fl ashes the fault code. If
contactors are energized and the voltage drops below
16 .0 volts the Unit Controller will de-energize the
contactors and fl ash the alarm. To trouble shoot check
the voltage between the “R” and “COM” at the ¼ inch
terminals on the board.
Smoke Purge Mode Alarm (36)
This is not an alarm but rather an indication the unit
has been placed in a smoke purge mode. Verify the
presence of 24 VAC between PURGE connection at
the P3 connector and “C” on the P1 connector. If 24
VAC is present and the unit is not supposed to be in the
Purge mode trace the fi eld wiring to determine why the
voltage is present.
High Duct Static Pressure Alarm (37)
This alarm indicates the duct static pressure has exceeded
the Duct Static Shutdown Setpoint. The problem could
be caused by a faulty Duct Static Pressure Transducer
input. To check measure the VDC input between
terminal DP+ wire 337 at the P21 connector and
terminal DP- wire 338 at the P21 connector. Compare
the voltage verses the duct pressure the control indicates
to Table 8-2 in this section of the manual. Also verify
that 24 VAC is present between terminals “COM” and
“EXC” at the duct static transducer.