Reach-In
P/N 0387183_V
2-5
HUSSMANN CORPORATION • BRIDGETON, MO 63044-2483 U.S.A.
EXPANSION VALVE ADJUSTMENT
Expansion valves must be adjusted to fully feed the
evaporator. Before attempting to adjust valves, make
sure the evaporator is either clear or only lightly
covered with frost, and that the merchandiser is
within 10 deg F (6.5 deg C) of its expected operating
temperature. Adjust valves as follows:
Method 1 (recommended): Attach a
sensing probe (either thermocouple
of thermistor) to the evaporator
outlet, under the clamp holding
the expansion valve bulb. Attach a
pressure probe to the access valve on
the suction line. Measure superheat
by subtracting the saturation
temperature at the measured
pressure from the measured outlet
temperature. Method 2: Attach two
sensing probes.
Note:
When using high glide refrigerants
(e.g., R-407A, R-448A), use the
evaporator pressure and subtract
the dew point from the coil outlet
refrigerant temperature to measure
the superheat level.
Attach two sensing probes (either
thermocouple or thermistor) to the
evaporator. Position one under the
clamp holding the expansion valve
bulb; securely tape the other to the
coil inlet line.
Some “hunting” of the expansion valve is normal.
The valve should be adjusted so that during the
hunting
The
greaTesT
DiffereNce
beTweeN
The
Two
probes
is
3–5
deg
f (1.7–2.8
deg
c).
With this
adjustment, during a portion of the hunting the
temperature difference between the probes will be less
than 3 deg F
(1.7
deg
c)
and at times 0.
Make adjustments of no more than 1/4 turn for
Balanced Port TEV and 1/2 turn at a time for
other valve models. Wait at least 15 minutes before
re checking the probe temperature or making further
adjustments.
Component Location in
RL / RM / RLN /
RLNI Models
Permit Number:
20-05195
Summary of Contents for RFLNS
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