Service Manual

32
SERVICING
COOLING ANALYSIS CHART
Complaint
System
Operating
Pressures
POSSIBLE CAUSE
DOTS IN ANALYSIS
GUIDE INDICATE
"POSSIBLE CAUSE"
SYMPTOM
System will not start Compressor will not start - fan runs Comp. and Cond. Fan will not start Evaporator fan will not start Condenser fan will not start Compressor runs - goes off on overload Compressor cycles on overload System runs continuously - little cooling Too cool and then too warm Not cool enough on warm days Certain areas too cool, others too warm Compressor is noisy Low suction pressure Low head pressure High suction pressure High head pressure
Test Method
Remedy
See Service Procedure Ref.
Pow er Failur e
•
Test Voltage S-1
Blow n Fuse
•••
Inspect Fuse Size & Type S-4
Loose Connection
•••
Inspect Connection - Tighten S-2
Shorted or Broken Wires
••••••
Test Circuits With Ohmmeter S-3
Open Overload
•••
Test Continuity of Overload S-17A
Faulty Thermostat
•• ••
Test continuity of Thermostat & Wiring S-3
Faulty Transformer
••
Check control circuit w ith voltmeter S-4
Shorted or Open Capacitor
•••
Test Capacitor S-15
Shorted or Grounded Compressor
••
Test Motor Windings S-17B
Compressor Stuck
••
Use Test Cord S-17D
Faulty Compressor Contactor
•• ••
Test continuity of Coil & Contacts S-7, S-8
2nd Stage Compressor Not Energized
•• ••
Test Unloader Solenoid (2 stage compressor only) S-17C
Faulty Ignition Control
•
Test Ignition Control S-313
Open Control Circuit
•
Test Control Circuit w ith Voltmeter S-4
Low Voltage
•••
Test Voltage S-1
Faulty Evap. Fan Motor
••
Repair or Replace S-16
Shorted or Grounded Fan Motor
••
Test Motor Windings S-16
Improper Cooling Anticipator
••
Check resistance of Anticipator S-3
Shortage of Refrigerant
•• ••
Test For Leaks, Add Refrigerant S-103
Restricted Liquid Line
•• ••
Replace Restricted Part S-112
Dirty Air Filter
••••
Inspect Filter-Clean or Replace
Dirty Indoor Coil
••••
Inspect Coil - Clean
Not enough air across Indoor Coil
••••
Speed Blow er, Check Duct Static Press S-200
Too much air across Indoor Coil
•
Reduce Blow er Speed S-200
Overcharge of Refrigerant
•• • ••
Recover Part of Charge S-113
Dirty Outdoor Coil
•• • •
Inspect Coil - Clean
Noncondensibles
•• •
Recover Charge, Evacuate, Recharge S-114
Recirculation of Condensing Air
•• •
Remove Obstruction to Air Flow
Infiltration of Outdoor Air
•••
Check Window s, Doors, Vent Fans, Etc.
Improperly Located Thermostat
••
Relocate Thermostat
Air Flow Unbalanced
••
Readjust Air Volume Dampers
System Undersized
••
Refigure Cooling Load
Broken Internal Parts
•
Replace Compressor
Inefficient Compressor
•••
Test Compressor Efficiency S-104
High Pressure Control Open
•
Reset And Test Control S-12
Unbalanced Pow er, 3PH
•••
Test Voltage
Wrong Type Expansion Valve
••• • ••
Replace Valve
Expansion Device Restricted
••• • ••
Remove restriction or replace expansion device
Expansion Valve Bulb Loose
•
Tighten Bulb Bracket
Inoperative Expansion Valve
•• •
Check Valve Operation S-110
Loose Hold-dow n Bolts
•
Tighten Bolts
No Cooling
Unsatisfactory
Cooling