Carrier VECTOR 6500 - Defrost Cycle Malfunction; Unit will Not Heat or Has Insufficient Heating; Unit will Not Terminate Cooling; Unit will Not Terminate Heating

9−5
62-11389
Indication/Trouble
Possible Causes Action/Refer-
ence Section
9.4.4 Unit Will Not Terminate Cooling
Unit fails to stop cooling
Temperature sensor malfunction 8.9.10
Contactor (CCON) stuck closed Check
Microprocessor improperly set
Check set point
Check whether
microprocessor
is set at °C or
°F
9.4.5 Unit Will Not Heat Or Has Insufficient Heating
Unit will not heat or has insuffi-
cient heat
Heater(s) defective 8.9.5
Heater contactors or coil defective Replace
Defective wiring / connectors Replace
Loose terminal connections Tighten
Low voltage 9.3
No or restricted air flow 9.4.10
Temperature sensor malfunction 8.9.10
Compressor contactor stuck closed Check
9.4.6 Unit Will Not Terminate Heating
Unit fails to stop heating
Microprocessor temperature improperly set Reset
Microprocessor malfunction 9.6
Temperature sensor malfunction 8.9.10
9.4.7 Defrost Cycle Malfunction
Will not initiate defrost
automatically
Defrost timer has not expired Check/Reset
Defrost air switch (DAS) malfunction 8.8.9
DTT is above 40F (4.4C) Cool Down
Loose terminal connections (DAS) Tighten
Will not initiate defrost manually
Keypad defective 8.4.4
Loose terminal connections between keypad and micro-
processor
Tighten
DTT is above 40F (4.4C) Cool Down
Unit has been running less than 15 seconds Try again
Initiates but does not defrost
Heater contactor or coil defective Replace
Heater(s) burned out 8.9.5
Evaporator fan contactor stuck closed Check
Frequent defrost
Defrost air switch (DAS) out of adjustment 8.8.9
Wet load Normal
Does not terminate or
cycles on defrost.
Defrost air switch (DAS) out of adjustment 8.8.9
DTT malfunction 8.9.10
Refrigerated Compartment
Hot Load Allow time to
pull down
Defective or insufficient refrigerated compartment insula-
tion or air leak
Correct