Rheem RP13 Installation Instructions Manual page 46

DIAGNOSTICS
Service Analyzer Charts
THERMOSTATIC EXPANSION VALVES (cont.)
SYMPTOM
Compressor flood
back upon start-up
Superheat is low to
normal with low
suction pressure
Superheat and
suction pressure
fluctuate (valve is
hunting)
Valve does not
regulate at all
46
POSSIBLE CAUSE
Refrigerant drainage from flooded evaporator
Inoperable crankcase heater or crankcase heater
needed
Any of the causes listed under symptoms of
Electrical problems on page 45
Unequal evaporator circuit loading
Low load or airflow entering evaporator coil
Expansion valve is oversized
Sensing bulb is affected by liquid refrigerant or
refrigerant oil flowing through suction line
Unequal refrigerant flow through evaporator
circuits
Moisture freezing and partially blocking TEV
External equalizer line not connected or line
plugged
Sensing bulb lost its operating charge
Valve body damaged during soldering or by
improper installation
REMEDY
Install trap riser to the top of the evaporator coil�
Replace or add crankcase heater�
Any of the solutions listed under solutions of Electrical
problems on page 45
Ensure airflow is equally distributed through evaporator.
Check for blocked distributor tubes�
Ensure blower is moving proper air CFM�
Remove/Correct any airflow restriction.
Install correct TEV�
Relocate sensing bulb in another position around the
circumference of the suction line�
Ensure sensing bulb is located properly�
Check for blocked distributor tubes�
Recover refrigerant, change filter-drier, evacuate system,
and recharge�
Connect equalizer line in proper location, or remove any
blockage�
Replace TEV�
Replace TEV�