Troubleshooting A Frozen Evaporator Coil - Traulsen G Series Manual

II. c - Troubleshooting a Frozen Evaporator Coil
Table 12 is intended to aid in diagnosing the root cause of a frozen evaporator coil on a
Traulsen upright reach-in refrigerator or freezer. This may not cover all situations that may arise
in the field and final diagnosis of field based equipment is the sole responsibility of the
technician contracted to perform any work required.
Potential Causes
Cabinet Sensor out of tolerance
(See TTB006 Sensors for sensor
troubleshooting)
Coil Sensor out of tolerance
(See TTB006 Sensors for sensor
troubleshooting)
Ambient Air Infiltration
Compressor relay stuck closed
Lack of Air Flow
Refrigeration System (Traulsen
recommends the refrigeration system be
tested using the methods outlined in
TTB009)
Defrost Heater
Control Settings
Table 12
Frozen Evaporator Troubleshooting Table
Details
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Color: Green
Control parameter
Reads return air
Compressor cycles off of cabinet sensor value
Color: Blue
Control parameter
Reads evaporator coil temperature
Terminates defrost @ 45⁰F (7.2⁰C)
Fan delay
Door(s) not closing properly
Gasket(s) not sealing properly
Door(s) left open for extended periods of time
Evaporator hump cover not sealed properly
Coil voltage 12VDC
Coil wires: Pink
Contacts
o Common: Black wire
o N/O: Blue wire
Evaporator fan motor not functioning
Obstruction in air duct or at evaporator coil
Low charge
Restricted metering device
Moisture/contaminates in the system
Defrost heater open
Defrost heater circuit or relay open
Set point to low (refrigerator only)
Control parameters:
o
(depending on the age of control system)
Defrost lockouts set to frequently
o Control parameters:
or &
, , ,
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