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Compressor Rotation
CAUTION
EQUIPMENT DAMAGE HAZARD
Failure to follow this caution can result in premature wear
and damage to equipment.
Scroll compressors can only compress refrigerant if
rotating in the right direction. Reverse rotation for
extended times can result in internal damage to the
compressor. Scroll compressors are sealed units and
cannot be repaired on site location.
On 3-phase units with scroll compressors, it is important to be cer-
tain compressor is rotating in the proper direction. To determine
whether or not compressor is rotating in the proper direction:
1.
Connect service gauges to suction and discharge pressure
fittings.
2.
Energize the compressor.
3.
The suction pressure should drop and the discharge pres-
sure should rise, as is normal on any start-up.
If the suction pressure does not drop and the discharge pressure
does not rise to normal levels:
1.
Note that the evaporator fan is probably also rotating in
the wrong direction.
2.
Turn off power to the unit and install lockout tag.
3.
Reverse any two of the unit power leads.
4.
Re-energize to the compressor. Check pressures.
The suction and discharge pressure levels should now move to
their normal start-up levels.
NOTE: When the compressor is rotating in the wrong direc-
tion, the unit will make an elevated level of noise and will not
provide cooling.
Cooling
Set space thermostat to OFF position. To start unit, turn on main
power supply. Set system selector switch at COOL position and
fan switch at AUTO. position. Adjust thermostat to a setting be-
low room temperature. Compressor starts on closure of contactor.
Check unit charge. Refer to Refrigerant Charge section on
page 15.
Reset thermostat at a position above room temperature. Com-
pressor will shut off. Evaporator fan will shut off after a
30-second delay.
To shut off unit, set system selector switch at OFF position. Reset-
ting thermostat at a position above room temperature shuts unit off
temporarily until space temperature exceeds thermostat setting.
Heating
To start unit, turn on main power supply. Set system selector
switch to the HEAT position and set thermostat at a setting above
room temperature. Set fan to AUTO position.
First stage of thermostat energizes the first stage of the electric
heaters. Second stage of thermostat energizes the second stage
of electric heaters (if installed). Check heating effects at air
supply grille(s).
If electric heaters do not energize, reset limit switch (located on
supply-fan scroll) by pressing button located between termi-
nals on the switch.
To shut unit off, set system selector switch to the OFF position.
Resetting thermostat at a position below room temperature
temporarily shuts unit off until space temperature falls below
thermostat setting.
Ventilation (Continuous Fan)
Set fan and system selector switches at ON and OFF positions, re-
spectively. Evaporator fan operates continuously to provide con-
stant air circulation.
FASTENER TORQUE VALUES
Table 16 — Torque Values
Stator Motor Mounting
Screws
Fan Rotor Mounting
Screws (2.4 HP)
Fan Rotor Mounting
Screws (3 and 5 HP)
Fan Deck Bracket Screws
Fan Casing Screws
Heat Shield Screws
Condenser Motor
Mounting Screws
Condenser Hub Set Screw 84 in.-lb (9.5 Nm) + 12 in.-lb (1.5 Nm)
Compressor Mounting
Bolts
Tandem Rail Mounting
Bolts
Crankcase Heater
58
50 in.-lb (5.7 Nm) + 5 in.-lb (0.6 Nm)
50 in.-lb (5.7 Nm) + 5 in.-lb (0.6 Nm)
30 in.-lb (3.4 Nm) + 2 in.-lb (0.2 Nm)
50 in.-lb (5.7 Nm) + 5 in.-lb (0.6 Nm)
10 in.-lb (1.1 Nm) + 1 in.-lb (0.1 Nm)
30 in.-lb (3.4 Nm) + 2 in.-lb (0.2 Nm)
30 in.-lb (3.4 Nm) + 2 in.-lb (0.2 Nm)
12 ft-lb (16.2 Nm) + 2 ft-lb (2.7 Nm)
8 ft-lb (10.8 Nm) + 0.5 ft-lb (0.6 Nm)
22.5 in.-lb (2.5 Nm) + 2.5 in.-lb (0.3 Nm)
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Troubleshooting
