Abnormal Pressures; Abnormal Noise Or Vibrations - Carrier PrimeLINE 69NT40-561-200 Operation And Service Manual

CONDITION
Will not initiate defrost
manually
Initiates but relay (DR) drops
out
Initiates but does not defrost
Frequent defrost
6.7

ABNORMAL PRESSURES

High discharge pressure
Low suction pressure
Suction and discharge
pressures tend to equalize
when unit is operating
6.8

ABNORMAL NOISE OR VIBRATIONS

Compressor
Condenser or Evaporator
Fan
POSSIBLE CAUSE
Manual defrost switch defective
Keypad is defective
Defrost temperature sensor open
Low line voltage
Heater contactor or coil defective
Heater(s) burned out
Wet load
Condenser coil dirty
Condenser fan rotating backwards
Condenser fan inoperative
Refrigerant overcharge or non-condensibles
Discharge service valve partially closed
Electronic expansion valve (EEV) control malfunction Replace
Incorrect software and/or controller configuration
Failed suction pressure transducer (SPT) or evapora-
tor pressure transducer (EPT)
Suction service valve partially closed\
Filter drier partially plugged
Low refrigerant charge
No evaporator air flow or restricted air flow
Excessive frost on evaporator coil
Evaporator fan(s) rotating backwards
EEV control malfunction
Failed digital unloader valve (DUV)
Compressor operating in reverse
Compressor cycling/stopped
Failed digital unloader valve (DUV)
Compressor start up after an extended shutdown
Brief chattering when manually shut down
Compressor operating in reverse
Loose mounting bolts or worn resilient mounts
Loose upper mounting
Loose slugging
Bent, loose or striking venturi
Worn motor bearings
Bent motor shaft
6–3
REMEDY/REFERENCE
SECTION
Replace
Replace
Replace
Section 3.3
Replace
Section 7.15
Normal
Section 7.11.2
Section 7.11
Section 7.12
Section 7.3
Open
Check
Replace
Open
Section 7.14
Section 7.3
Section 7.15
Section 6.6
Section 7.17.3
Replace
Replace
Section 6.15
Check
Replace
Normal
Section 6.15
Tighten/Replace
Section 7.9.1
Section 7.15
Check
Section 7.12/Section 7.17
Section 7.12/Section 7.17
T-362