Sterling AquaSnap 30RA010-055 - Manual (Page 61)

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• Thoroughly rinse all surfaces with low velocity clean
water using downward rinsing motion of water spray
nozzle. Protect fins from damage from the spray nozzle.
CONDENSER SECTION — Condenser fan motors and fans
can be serviced by removal of outlet grilles or side panels. See
Fig. 31. Be sure the wire fan guard is in place over each fan be-
fore starting unit. See Fig. 32 and 33 for proper fan adjustment.
Fan mounting system is designed for fan to drop all the way on
the motor shaft to be correctly located in the orifice. Tighten
fan hub securely on motor shaft with setscrews which bear
against the key. Be sure to replace the plastic fan cap and se-
cure in place with the four locking clips to keep water and de-
bris out of shaft area.
Check Refrigerant Feed Components
THERMOSTATIC EXPANSION VALVE (TXV) — The TXV
controls the flow of liquid refrigerant to the cooler by main-
taining constant superheat of vapor leaving the cooler. There is
one valve per refrigerant circuit. The valve(s) is activated by a
temperature-sensing bulb(s) strapped to the suction line(s). For
proper TXV sensing bulb location, see Fig. 34.
The valve is factory-set to maintain between 8 and 12 F
(4.4 and 6.7 C) of superheat entering the compressor(s). Ele-
vate head pressure to 280 psig (1930 kPa) by blocking the air-
flow through the condenser. Check the superheat during opera-
tion after conditions have stabilized. A factory-installed tem-
perature well is in each suction line for this purpose. If
necessary, adjust the superheat to prevent refrigerant floodback
to the compressor. Adjust TXVs
1 /
2
turn at a time, allowing the
circuit to stabilize between adjustments. Turn stem counter-
clockwise to decrease superheat and clockwise to increase su-
perheat.
FILTER DRIER — The function of the filter drier is to main-
tain a clean, dry system. The moisture indicator (described
below) indicates any need to change the filter drier. The filter
drier is a sealed-type drier. When the drier needs to be
changed, the entire filter drier must be replaced.
NOTE: Dual circuit (032-055 sizes) units have 1 filter drier per
circuit.
MOISTURE-LIQUID INDICATOR — The indicator is located
immediately ahead of the TXV to provide an indication of the
refrigerant moisture content. It also provides a sight glass for
refrigerant liquid. Clear flow of liquid refrigerant (at full unit
loading) indicates sufficient charge in the system. Bubbles in the
sight glass (at full unit loading) indicate an undercharged system
or the presence of noncondensables. Moisture in the system,
measured in parts per million (ppm), changes the color of the
indicator as follows:
Green (safe) —Moisture is below 45 ppm
Yellow-Green (caution) — 45 to 130 ppm
Yellow (wet) — above 130 ppm
The unit must be in operation at least 12 hours before the
moisture indicator gives an accurate reading, and must be in
contact with liquid refrigerant. At the first sign of moisture in
the system, change the corresponding filter drier.
NOTE: Dual circuit (032-055 sizes) units have one indicator
per circuit.
MINIMUM LOAD VALVE — On units equipped with the
factory-installed capacity reduction option, a solenoid valve
(minimum load valve) is located between the discharge line
and the cooler entering-refrigerant line. The MBB cycles the
solenoid to perform minimum load valve function.
Harsh Chemical and Acid Cleaners — Harsh chemical,
household bleach or acid cleaners should not be used to
clean outdoor or indoors coils of any kind. These cleaners
can be very difficult to rinse out of the coil and can acceler-
ate corrosion at the fin/tube interface where dissimilar
materials are in contact. If there is dirt below the surface of
the coil, use the Environmentally Sound Coil Cleaner as
described above.
High Velocity Water or Compressed Air — High veloc-
ity water from a pressure washer, garden hose or com-
pressed air should never be used to clean a coil. The force
of the water or air jet will bend the fin edges and increase
airside pressure drop. Reduced unit performance or nui-
sance unit shutdown may occur.
PUMP
ACCESS SERVICE
DOOR
CONTROL
ACCESS
FAN BLADE BOTTOMS
OUT ON MOTOR SHAFT
PLASTIC FAN
PROPELLER
CLEARANCE OF 0.25 INCHES
(6.4 MM) FOR STANDARD
CONDENSER FANS
FAN DECK
SURFACE
FAN ORIFICE
Fig. 31 — 30RA Access Panels
Fig. 32 — Condenser-Fan Mounting
Fig. 33 — Condenser-Fan Position (Standard Fan)