28
For average scale deposit, allow solution to remain in con-
denser overnight. For heavy scale deposit, allow 24 hours.
Drain condenser and flush with clean water. Follow acid manu-
facturer’s instructions.
Compressor —
Conduct annual amperage checks to in-
sure that amp draw is no more than 10% greater than indicated
on the serial plate data.
Fan Motors —
All units have lubricated fan motors. Fan
motors should never be lubricated unless obvious, dry opera-
tion is suspected. Periodic maintenance oiling is not recom-
mended, as it will result in dirt accumulating in the excess oil
and cause eventual motor failure. Conduct annual dry opera-
tion check and amperage check to ensure amp draw is no more
than 10% greater than indicated on serial plate data.
Belt —
Check that the belt is tight. Retighten if needed. Re-
place if it is split or cracked.
Air Coil —
The air coil must be cleaned to obtain maximum
performance. Check once a year under normal operating condi-
tions and, if dirty, brush or vacuum clean. Care must be taken
not to damage the aluminum fins while cleaning.
Checking System Charge —
Units are shipped with
full operating charge. If recharging is necessary:
1. Insert thermometer bulb in insulating rubber sleeve on
liquid line near filter drier. Use a digital thermometer for
all temperature measurements. DO NOT use a mercury
or dial-type thermometer.
2. Connect pressure gage to discharge line near compressor.
3. After unit conditions have stabilized, read head pressure
on discharge line gage.
NOTE: Operate unit a minimum of 15 minutes before
checking charge.
4. From standard field-supplied Pressure-Temperature chart
for R-410A, find equivalent saturated condensing
temperature.
5. Read liquid line temperature on thermometer; then
subtract from saturated condensing temperature. The dif-
ference equals subcooling temperature.
Refrigerant Charging
NOTE: Do not vent or depressurize unit refrigerant to atmo-
sphere. Remove and recover refrigerant following accepted
practices.
Air Coil Fan Motor Removal
Motor power wires need to be disconnected from motor
terminals before motor is removed from unit.
1. Shut off unit main power supply.
2. Loosen bolts on mounting bracket so that fan belt can be
removed.
3. Loosen and remove the 2 motor mounting bracket bolts
on left side of bracket.
4. Slide motor/bracket assembly to extreme right and lift out
through space between fan scroll and side frame. Rest
motor on a high platform such as a step ladder. Do not
allow motor to hang by its power wires.
Blower Fan Sheaves —
Factory-supplied drives are
pre-aligned and tensioned, however, it is recommended that the
belt tension and alignment be checked before starting the unit.
Always check the drive alignment after adjusting belt tension.
Sheave and belt information is shown in Table 17.
Each factory-assembled fan, shaft, and drive sheave assem-
bly is precision aligned and balanced. If excessive unit
vibration occurs after field replacement of sheaves, the unit
should be rebalanced. To change the drive ratio, follow the
steps in the Blower Fan Performance Adjustment section.
After 1 to 3 minutes of operation, check the belt tension.
Also check tension frequently during the first 24 hours of oper-
ation and adjust if necessary. Periodically check belt tension
throughout the run-in period, which is normally the initial
72 hours of operation.
ALIGNMENT — Make sure that fan shafts and motor shafts
are parallel and level. The most common causes of misalign-
ment are nonparallel shafts and improperly located sheaves.
Where shafts are not parallel, belts on one side are drawn tight-
er and pull more than their share of the load. As a result, these
belts wear out faster, requiring the entire set to be replaced be-
fore it has given maximum service. If misalignment is in the
sheave, belts enter and leave the grooves at an angle, causing
excessive belt and sheave wear.
Shaft Alignment — Check shaft alignment by measuring the
distance between the shafts at 3 or more locations. If the dis-
tances are equal, then the shafts are parallel.
Sheave Alignment
1. To check the location of the fixed sheaves on the shafts,
use a straightedge or a piece of string. If the sheaves are
properly aligned, the string will touch them at the points
indicated by the arrows in Fig. 24. Rotate each sheave a
half revolution to determine whether the sheave is wob-
bly or the drive shaft is bent. Correct any misalignment.
2. With sheaves aligned, tighten cap screws evenly and
progressively.
Fig. 23 — Forced Circulation Method
S
UCTION
PUMP
S
UPPORT
TANK
FINE ME
S
H
S
CREEN
RETURN
GA
S
VENT
PUMP
PRIMING
CONN.
GLOBE
VALVE
S
S
UPPLY
1-IN.
(25 mm)
PIPE
CONDEN
S
ER
REMOVE WATER
REGULATING VALVE
WARNING
To prevent personal injury, wear safety glasses and gloves
when handling refrigerant. Do not overcharge system —
this can cause compressor flooding.
CAUTION
Before attempting to remove fan motors or motor mounts,
place a piece of plywood over evaporator coils to prevent
coil damage.
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