Service Manual

30
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.
Power Failure
•
Test Voltage S-1
Blown Fuse
•••
Inspect Fuse Size & Type S-4
Loose Connection
•••
Inspect Connecti on - Tighten S-2
Shorted or Broken Wires
••••••
Test Circuits With Ohmmeter S-3
Open Over load
•••
Test Continuity of Overload S-17A
Faulty Thermostat
•• ••
Test continuity of Thermostat & Wiring S-3
Faulty Tra nsformer
••
Check control circuit with voltmeter S-4
Shorted or Open Capacitor
•••
Test Capacitor S-15
Shorted or Grounded Compressor
••
Test Motor Windings S-17B
Co mpre sso r Stuck
••
Use Test Cord S-17D
Faulty Compressor Contactor
•• ••
Test continuity of Coil & Contacts S-7, S-8
Faulty Ignition Control
•
Test Ignition Control S-313
Open Control Circuit
•
Test Control Circuit with 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 Cooli ng Antici pator
••
Check resistance of Anticipator S-3
Shortage of Refrigerant
•• ••
Test For Leaks, Add Refrigerant S-103
Restricted Liquid Line
•• ••
Replace Restricted Part S-112
Di rty Air Fil te r
••••
Inspect Filter-Clean or Replace
Dirty Indoor Coil
••••
Inspect Coil - Clean
Not enough air across Indoor Coil
••••
Speed Blower , Check Duct Static Press S-200
Too much air across Indoor Coil
•
Reduce Blower 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
Infil trati on of Outdoor Air
•••
Check Windows, Doors, Vent Fans, Etc.
Improperly Located Thermostat
••
Relocate Thermostat
Air Flow Unbalanced
••
Readjust Air Volume Dampers
System Undersized
••
Refigure Cool ing Load
Broken Interna l Parts
•
Replace Compressor
Inefficient Compressor
•••
Test Compressor Efficiency S-104
High Pressure Control Open
•
Reset And Test Control S-12
Unbalanced Power, 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-down Bolts
•
Tighten Bolts
Faulty Reversing Valve
•
Replace Valve or Solenoid S-21, 122
Faulty Defrost Control
•
Test Control S-24
Faulty Defrost Thermostat Test Defrost Thermostat S- 25
Flowrator Not Seating Properly
•••
Check Flow rator & Seat or Replace Flow rator S-111
No Cooling
Unsatisfactory
Cooling