REMEDY/

CONDITION

POSSIBLE CAUSE

REFERENCE

 

 

SECTION

5.11 THERMOSTATIC EXPANSION VALVE MALFUNCTION

 

 

 

 

 

Low refrigerant charge

6.4/6.6

 

External equalizer line plugged

Open

 

Wax, oil or dirt plugging valve or orifice Ice formation at

6.26

Low suction pressure with high

valve seat

 

Superheat too high

6.4/6.6

superheat

Power assembly failure

6.26.c

 

 

Loss of element/bulb charge

6.26

 

Broken capillary

6.26

 

Foreign material in valve

6.26

High suction pressure with low

Superheat setting too low

6.26.c

External equalizer line plugged Ice holding valve open

Open

superheat

Foreign material in valve

6.4/6.5 6.26

 

 

 

 

Liquid slugging in compressor

Pin and seat of expansion valve eroded or held open by

6.26

foreign material

 

 

 

Fluctuating suction pressure

Improper bulb location or installation

6.26

Low superheat setting

6.26.c

 

5.12 POWER AUTOTRANSFORMER MALFUNCTION

 

 

 

 

 

Circuit breaker (CB-1 or CB-2) tripped

Check

Unit will not start

Power transformer defective

6.22

Power source not turned ON

Check

 

 

460 VAC power plug is not inserted into the receptacle

2.4

 

 

 

5.13 WATER-COOLED CONDENSER OR WATER PRESSURE SWITCH

 

 

 

 

High discharge pressure

Dirty coil

6.28

Noncondensibles

 

 

 

Condenser fan starts and stops

Water pressure switch malfunction

Check

Water supply interruption

 

 

 

T-268-07

5-4

Page 94
Image 94
Carrier 69NT40-511-199, 69NT40-521 Power Autotransformer Malfunction, WATER-COOLED Condenser or Water Pressure Switch