Rheem FO13C Series Installation Instructions Manual page 44

DIAGNOSTICS
Service Analyzer Charts
FLOODING
SYMPTOM
Poor system control
using a TEV
THERMOSTATIC EXPANSION VALVES
SYMPTOM
High Superheat, Low
Suction Pressure
(superheat over
15°F [-9°C])
Valve feeds too much
refrigerant, with low
superheat and higher
than normal suction
pressure
44
POSSIBLE CAUSE
Loose sensing bulb
Bulb in wrong location
Wrong size TEV
Improper superheat setting (less than 5°F [-15°C])
POSSIBLE CAUSE
Moisture freezing and blocking valve
Dirt or foreign material blocking valve
Low refrigerant charge
Vapor bubbles in liquid line
Misapplication of internally equalized valve
Plugged external equalizer line
Undersized TEV
Loss of charge from power head sensing bulb
Charge migration from sensing bulb to power
head (Warm power head with warm, wet cloth.
Does valve operate correctly now?)
Moisture causing valve to stick open.
Dirt or foreign material causing valve to stick
open
TEV seat leak (a gurgling or hissing sound is
heard AT THE TEV during the off cycle, if this is
the cause). NOT APPLICABLE TO BLEED PORT
VALVES.
Oversized TEV
Incorrect sensing bulb location
Low superheat adjustment
Incorrectly installed, or restricted external
equalizer line
REMEDY
Secure the bulb and insulate.
Relocate bulb.
Use correct replacement.
Replace TEV.
REMEDY
Recover charge, install fi lter-drier, evacuate system,
recharge.
Recover charge, install fi lter-drier, evacuate system,
recharge.
Correct the charge.
Remove restriction in liquid line. Correct the refrigerant
charge.
Remove noncondensible gases.
Size liquid line correctly.
Use correct TEV.
Remove external equalizer line restriction.
Replace with correct valve.
Replace power head or complete TEV.
Ensure TEV is warmer than sensing bulb.
Recover refrigerant, replace fi lter-drier, evacuate system,
and recharge.
Recover refrigerant, replace fi lter drier, evacuate system,
and recharge.
Replace the TEV.
Install correct TEV.
Install bulb with two mounting straps, in 2:00 or 4:00
position on suction line, with insulation.
Replace TEV.
Remove restriction, or relocate external equalizer.