Thermo Scientific Jewett CTF306 Blood Plasma Freezers
Installation and Operation
TROUBLESHOOTING SERVICE CHART
SYMPTOM
POSSIBLE CAUSE
POSSIBLE CORRECTIVE STEP
1. Excessive load.
1. Reduce load or add additional equipment.
J
High suction
pressure.
2. Expansion valve overfeeding.
2. Check remote bulb. Adjust superheat.
1. Insufficient refrigerant in system.
1. Check for leaks. Repair and add charge.
2. Restriction in refrigeration system. Most
notably the liquid line filter drier or
capillary.
2. Determine location and remove.
K
Low suction
pressure.
3. Expansion valve malfunctioning.
3. Check and reset for proper superheat.
1. Expansion valve passing excess
refrigerant or is oversized.
1. Readjust valve or replace with smaller
valve.
2. Expansion valve stuck open.
2. Clean valve of foreign particles, and
replace if necessary.
3. Evaporator fan motors not running.
3. Determine reason and correct. Check
door switch.
L
Suction line
frosted or
sweating.
4. System overcharged with refrigerant.
4. Correct the charge.
1. Restriction in liquid line filter drier.
1. Determine location and remove.
M
Liquid line
frosted or
sweating
2. Liquid line shutoff valve partially closed. 2. Open valve.
1. Defrost duration too long.
1.Adjust defrost termination.
2. Fan delay not delaying fans after defrost
period.
2. Defective fan delay thermostat. Replace.
3. Defective timer.
3. Replace.
N
Ice
accumulating
on ceiling
around
evaporator
and/or on fan
guards or
blades.
4. Too many defrost cycles per day.
4. Adjust timer for less defrost cycles.
1. Coil temperature not getting above
freezing point during defrost.
1. Check heater operation, or hot gas
solenoid valve.
2. Not enough defrost cycles per day.
2. Adjust timer for more defrost cycles.
3. Defrost cycle too short.
3. Adjust timer for longer defrost cycle.
4. Poor door seal.
4. Adjust door latch, install new gasket.
O
Evaporator
coil not
clearing of
frost during
defrost cycle.
5. Defective timer or defrost thermostat.
5. Replace defective component.
1. Defective heater.
1. Replace heater.
2.Unit not pitched properly.
2. Check and adjust if necessary.
3. Drain line plugged.
3. Clean drain line.
4. Defective drain line heater.
4. Replace heater.
5. Poor contact between drain pan and
heater element.
5. Repair.
P
Ice
accumulating
in drain pan.
6. Defective timer or defrost thermostat.
6. Replace defective component.
NOTE:
Jewett Refrigerators and Freezers are designed to operate in areas that are heated to 60
°
F (15.6
°
C). Installation in
unheated areas may require a low temperature compressor protection kit for satisfactory operation.
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