PRE-START-UP
Failure to observe the following warnings could result
in serious personal injury:
1. Follow recognized safety practices and wear protec-
tive goggles when checking or servicing refrigerant
system.
2. Do not operate compressor or provide any electric
power to unit unless compressor terminal cover is in
place and secured.
3. Do not remove compressor terminal cover until all
electrical sources are disconnected.
4. Relieve all pressure from system before touching or
disturbing anything inside terminal box if refrigerant
leak is suspected around compressor terminals. Use
accepted methods to recover refrigerant.
5. Never attempt to repair soldered connection while re-
frigerant system is under pressure.
6. Do not use torch to remove any component. System
contains oil and refrigerant under pressure. To re-
move a component, wear protective goggles and pro-
ceed as follows:
a. Shut off electrical power to unit.
b. Relieve all pressure from system using both high-
and low-pressure ports. Use accepted methods to
recover refrigerant.
c. Cut component connection tubing with tubing cut-
ter and remove component from unit.
d. Carefully unsweat remaining tubing stubs when nec-
essary. Oil can ignite when exposed to torch flame.
Proceed as follows to inspect and prepare the unit for ini-
tial start-up:
1. Remove all access panels.
2. Read and follow instructions on all WARNING, CAU-
TION, and INFORMATION labels attached to or shipped
with unit.
3. Make the following inspections:
a. Inspect for shipping and handling damages such as bro-
ken lines, loose parts, or disconnected wires.
b. Inspect for oil at all refrigerant tubing connections and
on unit base. Detecting oil generally indicates a re-
frigerant leak. Leak-test all refrigerant tubing connec-
tions using electronic leak detector, halide torch, or
liquid-soap solution.
c. Inspect all field- and factory-wiring connections. Be
sure that connections are completed and tight.
d. Inspect coil fins. If damaged during shipping and han-
dling, carefully straighten fins with a fin comb.
4. Verify the following conditions:
a. Make sure that outdoor-fan blades are correctly posi-
tioned in fan orifice. Refer to Condenser Fan Adjust-
ment section on page 29 for more details.
b. Make sure that air filter(s) is in place.
c. Make sure that condensate drain trap is filled with wa-
ter to ensure proper drainage.
d. Make sure that all tools and miscellaneous loose parts
have been removed.
START-UP
Unit Preparation —
Make sure that unit has been in-
stalled in accordance with these installation instructions and
applicable codes.
Operating Parameters —
The maximum outdoor
entering-air temperature is 115 F. The minimum entering
outdoor-air temperature is 45 F without Motormaster® head-
pressure control.
Return-Air Filters —
Make sure correct filters are in-
stalled in unit (see Table 1). Do not operate unit without return-
air filters.
Outdoor-Air Inlet Screen(s) —
Outdoor-air inlet
screen(s) must be in place before operating unit.
Compressor Mounting —
Compressors are inter-
nally spring mounted. Do not loosen or remove compressor
holddown bolts.
Internal Wiring —
Check all electrical connections in
unit control boxes; tighten as required.
Refrigerant Service Ports —
Each refrigerant sys-
tem has 4 Schrader-type service gage ports: one on the suc-
tion line, one on the liquid line, and 2 on the compressor
discharge line. Be sure that caps on the ports are tight.
Compressor Rotation —
On 3-phase units, it is im-
portant to be certain the scroll compressor is rotating in the
proper direction. To determine whether or not compressor is
rotating in the proper direction:
1. Connect service gages to suction and discharge pressure
fittings. Dedicated service gage set is recommended due
to compatiblity problems with R-407C and oil (POE) for
R-22 systems.
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.
3. Reverse any two of the unit power leads.
4. Turn on power to the compressor.
The suction and discharge pressure levels should now move
to their normal start-up levels.
NOTE: When the compressor is rotating in the wrong di-
rection, the unit makes an elevated level of noise and does
not provide heating/cooling.
Cooling —
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 below room
temperature. Compressor starts on closure of contactor.
Check unit charge. Refer to Refrigerant Charge section on
page 29.
Reset thermostat at a position above room temperature.
Compressor will shut off.
TO SHUT OFF UNIT — Set system selector switch at OFF
position. Resetting thermostat at a position above room tem-
perature shuts unit off temporarily until space temperature
exceeds thermostat setting. Units are equipped with Cycle-
LOC™ protection device. Unit shuts down on any safety trip
and remains off; an indicator light on the thermostat comes
on. Check reason for safety trip.
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