MAINTENANCE WITH Q & A
74
FROZEN COIL TROUBLESHOOTING PROCEDURES (OPTIONAL EQUIPMENT)
Frozen Coil Mode not engaged
Dewpoint not low enough, let wet coil remove moisture
before unit enters frozen coil mode
Solenoid valve not working
Check liquid line solenoid (Frozen Coil)
Check EPR bypass solenoid. Do they have power?
Frozen Coil T.E.V. out of
adjustment
Adjust T.E.V. to increase superheat
Verify Frozen Coil is turned on by the event
and/or switch on the control panel
Table 5-9: Frozen Coil Troubleshooting Procedures
HIGH/LOW LIMIT CONTROL TROUBLESHOOTING ROCEDURES
No display on
control panel
AC unit is not connected, or is
connected improperly
Check AC input connections and correct if necessary. If
connections are correct and the there is still no
display,
contact CSZ's Service Department.
Display indicates "- .
. ." and yellow
Repair or replace the thermocouple
Sensor is connected improperly
Check sensor locations, connections, and sensing
element. Repair or replace sensor as required
Place jumper wire across thermocouple terminals.
Indicator is fun
ctioning properly if display indicates
Display indicates "-
000" and flashes
Jumper W8 for °F/°C selection is
not installed or is installed
Install Jumper W8 in desired location for °F or °C
Control is in a LO or
HI LIMIT condi
tion
Actual temperature is below low
limit setpoint or above high limit
setpoint
Check low limit and high limit setpoints. If actual
temperature is not between low and high limit
setpoints, it cannot be reset, though alarm can be
silen
ced
If external reset switch is used, check wiring of external
reset switch
LO or HI LIMIT
temperature does
not appear accurate
Calibration adjustments incorrect
Perform field calibration procedure.
Table 5-10: High/Low Limit Control Troubleshooting Procedures
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