True Food Service Equipment, Inc.
INSTALLATION / OPERATION INSTRUCTIONS
4.If all operating conditions are normal, the voltage supply at the compressor terminals balanced and within limits, the compressor crankcase temperature within normal limits, and the amperage drawn within the specified range, the motor protector may be defective, and should be replaced.
If the operating conditions are normal and the compressor is running excessively hot for no observable reason, or if the amperage drawn is above the normal range and sufficient to repeatedly trip the protector, the compressor has internal damage and should be replaced.
IF THE COMPRESSOR RUNS BUT WILL NOT REFRIGERATE
1.Check the refrigerant charge. Check the evaporator surface to determine if it is evenly cold throughout, or if partially starved. A lack of charge may be indicated by light, fluffy frost at the evaporator inlet. Add refrigerant if necessary.
2.Check the compressor suction pressure. An abnormally low pressure may indicate a loss of refrigerant charge, a malfunctioning capillary tube, a lack of evaporator capacity possibly due to icing or low air flow, or a restriction in the system.
Often a restriction in a drier or strainer can be identified by frost or a decrease in temperature across the restriction due to the pressure drop in the line. This will be true only if liquid refrigerant
is in the line at the restricted point, since any temperature change due to restriction would be caused by the flashing of liquid into vapor as the pressure changes.
Any abnormal restriction in the system must be corrected.
3.Check the compressor discharge pressure. An abnormally high discharge pressure can cause a loss of capacity, and can be caused by a dirty condenser, a malfunctioning condenser fan, or air in the system.
4.If the suction pressure is high, and the evaporator and condenser are functioning normally, check the compressor amperage draw. An amperage draw near or above the nameplate rating indicates normal compressor or unit may have damaged valves.
An amperage draw considerably below the nameplate rating may indicate a broken suction reed or broken connecting rod in the compressor.
DIAGNOSIS AND REPLACEMENT OF FREEZER CABINET COMPONENTS
1.Defrost Time Clock
A.Check timer motor to be sure it runs.
B.Check contacts on the defrost timer.
C.Check solenoid windings for continuity to ensure contact switching.
D.Check to be sure defrost actuator pins are in proper position.
E.Check all wires in the timer for tightness to terminals and
broken wires.
2.Defrost Control On The Evaporator Drain Pan
A.If the defrost time is always
35minutes (or whatever duration the elapsed time adjustment is set at) and the fan motors do not delay after a defrost cycle and it has been determined that the solenoid in the defrost clock is functioning, change the defrost control in the evaporator
compartment in the top of the
freezer. This control is attached to the evaporator drain pan.
3.Coil Defrost Heater
A.Lower the evaporator cover. Disconnect the coil heater by removing the wire nuts at the point where the heater joins the electrical circuit of the freezer in the evaporator compartment. Check heater for continuity with an ohmmeter. If the heater is defective, cut the bale wires holding the heater to the coil and remove the heater. Replace with a new heater using bale wires provided.
4.Drain Tube Heater
A.Lower the evaporator cover. Disconnect the drain tube heater by removing the wire nuts at the point where the heater joins the electrical circuit of the freezer in the evaporator compartment. Check the drain tube heater with an ohmmeter.
B.If the drain tube heater is defective, disconnect the drain tube from the rigid plastic drain, bend the tabs that hold the evaporator drain pan to the evaporator cover and raise the drain pan so that the flexible heater is visible, pull heater out of the plastic drain tube and replace. Connect heater to the electrical circuit in the evaporator compartment.
5.Cabinet Temperature Control
A.Remove the two screws on the right side of the evaporator housing that holds the control mounting plate. Reach behind the evaporator housing on the control side of the cabinet and pull the control bulb out of the receptacle in the roof of the cabinet. Disconnect the wires from the control. Check control for continuity, replace if defective.
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