MAINTENANCE WITH Q&A
Page 5-11
FROZEN COIL TROUBLESHOOTING PROCEDURES (OPTIONAL EQUIPMENT)
Table 9. Frozen Coil Troubleshooting Procedures
Table 10. High/Low Limit Control Troubleshooting Procedures
HIGH/LOW LIMIT CONTROL TROUBLESHOOTING PROCEDURES
PROBLEM PROBABLE CAUSE CORRECTIVE ACTION
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
LO LIMIT LED
is ON.
Solenoid coil burned out Repair or replace the thermocouple
Display error 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 functioning properly if display indicates
room temperature
Display
indicates "-000"
and fl ashes
Jumper W8 for ºF/ºC selection is not
installed or is installed improperly
Install Jumper W8 in desired location for ºF or ºC
Control is in a
LO or HI LIMIT
condition and
cannot be reset
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
silenced
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 fi eld calibration procedure.
PROBLEM PROBABLE CAUSE CORRECTIVE ACTION
Coil not freezing
water
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
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