Specifications
START-UP
Use the t'ollowing information and Start-Up Checklist on
page CL-1 to check out unit PRIOR to start-up.
Unit Preparation -- Check that unit Ms been installed in
accor&mce with these installation instructions and all applica-
ble codes.
Compressor Mounting- Compressors are internally
spring mounted. Do not loosen or remove compressor hold-
down bolts.
Refrigerant Service Ports -- Each independent re-
ft-igerant system has a total of 3 Schrader-type service gage
ports per circuit. One port is located on the suction line, one on
the compressor dischaNe line, and one on the liquid line. Be
sure that caps on the ports are ti_lt.
Crankcase Heater(s)- Craalkcase heaters are ener-
gized as long as there is power to the unit and the compressor is
not operating.
IMPORTANT: Unit power must be on for 24 hours prior I
to start-up. Otherwise, damage to compressor may
I
result.
Compressor Rotation
hnproper wiring wilt cause compressor stoppage and alarm.
Correct wiring by switching leads as indicated below.
It is important to be certain the compressors are rotating in
the proper direction. To determine whether or not compressors
are rotating in the proper direction, use a phase-rotation meter
on the unit input power to check tbr L1-L2-L3 or cloclcwise ro-
tation or use the Service Test mode to energize a compressor. If
the compressor is rotating in the wrong direction, the controls
will stop the compressor and display alarm for "Circuit x Fail-
ure to Pressurize," where x is the corresponding A or B com-
pressor circuit.
NOTE: Indoor or outdoor thn rotation direction may not indi-
cate proper input power phase sequence, as some 3-phase units
use single-phase tan motors.
To correct the wrong compressor rotation direction, perform
the following procedure:
1. Turn offpower to the unit and lock out the power.
2. Switch any two of the incoming unit power leads.
3. Turn on power to the unit.
4. Verii_ corrected compressor rotation.
Internal Wiring--Check all electrical connections in
unit control boxes; tighten as required.
Subcooler Heat Exchanger (SHX) -- The subcool-
er heat exchanger adds approximately 10 to 15° F of sub-
cooling to the system. Check all valves aaldTXM
Evaporator Fan- Fan belt and variable pulleys are
factory-installed. See Tables 3-26 for tan performance data. Be
sure that fans rotate in the proper direction. See Tables 27 and
28 for air quantity limits. See Tables 29 and 30 for evaporator
tan motor specifications. See Tables 31 and 32 for accessory
FIOP static pressure. See Tables 33 and 34 for tan rpm at
various motor pulley settings. To alter tan performance, see
Evaporator Fan Performance Adjustment section on page 87.
Condenser Fans and Motors -- Condenser thns and
motors are factory set. Refer to Condenser-Fan Adjustment
section (page 88) as required.
Return-Air Filters -- Check that correct filters are in-
stalled in filter tracks (see Physical Data table in Installation
Instructions). Do not operate unit without return-air filters.
NOTE: For units with 4-in. filter option, units are shipped with
standard 2-in. filters. To install 4-in. filters, the filter spacers
must be removed.
Outdoor-Air Inlet Screens --Outdoor-air inlet screens
must be in place before operating unit.
Gas Heat (48PG Only) -- Veril_ gas pressures before
turning on heat as follows:
1. Turn off field-supplied manual gas stop, located external
to unit.
2. Connect pressure gage to supply gas tap, located on field-
supplied manual shutoffvalve (see Fig. 4).
3. Connect pressure gage to manifold pressure tap.
4. Turn on field-supplied manual gas stop. Enter Service
Test mode by setting TEST to "YES" using the Scrolling
Marquee display. Temporarily install the jumper wire
between "R" and "WI" on TB2. Use the Sin:ice Test
feature to set HT. 1 to ON (first stage of hea 0 using the
Scrolling Marquee.
5. After the unit has mn for several minutes, veri_ the sup-
ply gas press_ureis between 5.5 in. wg to 13.0 in. wg, and
the manitbld pressure is 2.95 in. wg on horizontal dis-
charge applications and 3.00 on vertical dischaige appli-
cations. If manifold pressure must be adjusted, refer to
Gas _alve Adjustment section.
NOTE: Supply gas pressure must not exceed 13.0 in. wg.
6. Set HT. 1to OFF using Scrolling Marquee.
7. Remove jumper wire if the unit will be operating under
thermostat mode. The jumper must remain if a space tem-
perature sensor (T-55, T-56, or T-58) wilt control the unit.
8. Exit Service Test mode by setting TEST to "NO" using
the Scrolling Marquee.
MANUALSHUTOFF
(FIELD SUP_ GAS
PRESSURE TAP
(1/8" NPT PLUG)
Fig. 4-- Field Gas Piping