-4-
Prep Models: UPT276 & UPT279
Refrigerant
R-134a
R-134a
Ambient Temperature
70
°
F
100
°
F
Suction Presure
Start of Cycle
41 lb.
43 lb.
End of Cycle
21 lb.
20 lb.
Discharge Pressure
Start of Cycle
61 lb.
90 lb.
End of Cycle
118 lb.
174 lb.
Prep Models: UPT488, UPT4812 & UPT4818
Refrigerant
R-134a
R-134a
Ambient Temperature
70
°
F
100
°
F
Suction Presure
Start of Cycle
30 psig
32 psig
End of Cycle
12 psig
21 psig
Discharge Pressure
Start of Cycle
89 psig
148 psig
End of Cycle
105 psig
171 psig
Prep Models: UPT6012, UPT6018 & UPT6024
Refrigerant
R-134a
R-134a
Ambient Temperature
70
°
F
100
°
F
Suction Presure
Start of Cycle
29 psig
34 psig
End of Cycle
12 psig
20 psig
Discharge Pressure
Start of Cycle
81 psig
128 psig
End of Cycle
99 psig
169 psig
Refrigerator Model: UHT48
Refrigerant
R-134a
R-134a
Ambient Temperature
70
°
F
100
°
F
Suction Presure
Start of Cycle
37 psig
36 psig
End of Cycle
12 psig
15 psig
Discharge Pressure
Start of Cycle
58 psig
130 psig
End of Cycle
102 psig
171 psig
Freezer Model: ULT48
Refrigerant
R-404A
R-404A
Ambient Temperature
70
°
F
100
°
F
Suction Presure
Start of Cycle
37 psig
41 psig
End of Cycle
14 psig
20 psig
Discharge Pressure
Start of Cycle
164 psig
250 psig
End of Cycle
210 psig
310 psig
Refrigerator Model: UHT60
Refrigerant
R-134a
R-134a
Ambient Temperature
70
°
F
100
°
F
Suction Presure
Start of Cycle
37 psig
38 psig
End of Cycle
11 psig
21 psig
Discharge Pressure
Start of Cycle
57 psig
109 psig
End of Cycle
99 psig
168 psig
Freezer Model: ULT60
Refrigerant
R-404A
R-404A
Ambient Temperature
70
°
F
100
°
F
Suction Presure
Start of Cycle
39 psig
40 psig
End of Cycle
11 psig
17 psig
Discharge Pressure
Start of Cycle
96 psig
126 psig
End of Cycle
214 psig
308 psig
IV. OPERATING DATA
VI. SERVICE PROCEDURES & ADJUSTMENTS (cont
’
d)
WARNING: CERTAIN PROCEDURES IN THIS SECTION REQUIRE ELECTRICAL TEST OR MEASUREMENTS WHILE
POWER IS APPLIED TO THE MACHINE. EXERCISE EXTREME CAUTION AT ALL TIMES. IF TEST POINTS ARE
NOT EASILY ACCESSIBLE, DISCONNECT POWER, ATTACH TEST EQUIPMENT AND REAPPLY POWER TO TEST.
-19-
VI. i - REHINGING DOOR (cont’d):
13) Install the top hinge plate to the cabinet.
14) Install the plug button and hinge plate pin in the
top of the door.
15) Install the door as outlined in “Section V. e”.
16) Adjust the door as outlined under “DOOR ADJUST-
MENT”.
VI. j - DEFROST TIMER SETTING:
WARNING: UNPLUG UNIT BEFORE SERVICING
The timer is preset with four, 23 to 25 minute defrost
cycles per day. You can only set when the defrost cycle
will start.
1) Use a screwdriver to turn cam clockwise until you
hear the contacts close. This position is when the
defrost cycle begins.
NOTE: The screwdriver slot is designed to be turned
clockwise only.
2) Continue to turn the cam until you hear the con-
tacts open. The defrost cycle has ended and it will be
six hours until the next occurrence.
3) You can continue turning the cam and position it
approximately within the six hour period.
VI. k - DOOR PERIMETER HEATER TEST:
WARNING: UNPLUG UNIT BEFORE SERVICING
1) Access the heater wire around the door frame.
2) Plug the unit in and verify 120 volt supply to the
heater.
3) The reading should be .25 amp.
VI. l - DEFROST HEATER TEST:
WARNING: UNPLUG UNIT BEFORE SERVICING
1) Access the heater lead wire to the defrost heater.
2) Plug the unit in, turn the defrost timer to start a de-
frost cycle.
3) Verify 120 volt supply to the heater.
4) The reading should be 3.7 amp (27” models) or 2.8
amp (48” & 60” models).
5) If you want to perform a continuity check:
a.
Unplug the unit.
b.
Disconnect the lead wires to the heater.
c.
Use an ohmmeter to check for 32.4 ohms (27”
models) or 41 ohms (48” & 60” models).
VI. m - DRAIN PAN HEATER TEST (n/a on 27” models):
WARNING: UNPLUG UNIT BEFORE SERVICING
1) Access the heater lead wire to the drain pan heater.
2) Plug the unit in, turn the defrost timer to start a de-
frost cycle.
3) Verify 120 volt supply to the heater.
4) The reading should be 1.04 amp.
5) If you want to perform a continuity check:
a.
Unplug the unit.
b.
Disconnect the lead wires to the heater.
c.
Use an ohmmeter to check for 110.0 ohms.
VII. ELECTRICAL OPERATION
VII. a- COMPONENT FUNCTION:
Compressor:
Pumps refrigerant through refrigeration lines and components.
Condenser Fan:
Draws air across condenser coil to aid in removing heat from the refrigerant and moves air across
compressor to aid in cooling the compressor.
Start Capacitor:
Wired in series with the start windings to help start compressor motor.
Thermal Overload:
Removes power from the compressor if the internal temperature of the compressor becomes too high (auto
reset).
Relay:
Senses current of run winding of compressor motor. Normally open contacts close when the run winding
draws a high amperage at start and brings the start capacitor and start windings into the circuit. As the motor
reaches operating speed (less amperage through run winding), the normally open contacts open and
removes the start capacitor and start windings from the circuit.
Evaporator Fan:
Draws air from the cabinet and moves the air through the evaporator coil.
Defrost Heater:
Defrosts evaporator coil and prevents water droplets from evaporator coil from freezing before they can drain
into the condensate pan. Operates only during defrost cycle.
High Limit Thermostat:
Monitors temperature at the evaporator. Opens circuit to defrost heater if coil
temperature reaches 40
°
F (
±
5
°
). Closes at 20
°
F (
±
5
°
).
Defrost Time Clock:
Controls defrost cycles on freezers. Four, 23 to 25 minute defrost per day. Start time can be set, but number
of defrosts is permanent.
Door Perimeter Heater:
Prevents condensate from forming on door frame.
Thermostat:
Monitors cabinet air temperature. Opens when cabinet temperature reaches set temperature.
Drain Pan Heater:
48” and 60” models only. Defrosts drain pan to prevent water droplets from evapaorator coil from freezing
before they can drain out. Operates only during defrost cycle.
Hi-Limit Press. Control:
48” and 60” models only. Monitors compressor’s head pressure. Removes power from compressor and
condenser fan motor, if head pressure becomes too high (manual reset for high pressure trip).
