Johnson Controls SA PD 180 THRU 240 - Manual (Page 17)

430645-YIM-D-0610
Johnson Controls Unitary Products 17
Piping And Electrical Connections
Piping connections are made from the rear of 7.5 thru 12.5 Ton
units and from the front of 15 thru 20 Ton units. Stubouts are
provided on the suction and liquid line service valves. Piping
can be routed to the unit from the left or right side.
Electrical connections for power and control wiring are made
from the right or left side of the electrical control box. See Table
9 and Figures 7 and 8 for piping sizes and electrical knockout
details.
Start-Up
Crankcase Heaters
The crankcase heaters must be energized at least 8 hours
before starting the compressors. To energize the crankcase
heaters, the main disconnect switch must be closed. During this
8 hour period, the system switch on the room thermostat must
be “OFF” to prevent the compressor from starting. Make sure
that the bottom of the compressor is warm to the touch to prove
crankcase heater operation.
Pre-Start Check
Before starting the unit, complete the following check list:
1. Have sufficient clearances been provided?
2. Has all foreign matter been removed from the interior of the
unit (tools, construction or shipping materials, etc.)?
3. Have the condenser fans been rotated manually to check
for free rotation?
4. Are all wiring connections tight?
5. Does the available power supply agree with the nameplate
data on the unit?
6. Is the control circuit transformer set for the proper voltage?
7. Have the fuses, disconnect switch and power wire been
sized properly?
8. Are all compressor mounting bolts properly secured?
9. Are any refrigerant lines touching each other or any sheet
metal surface? Rubbing due to vibration could cause a
refrigerant leak.
10. Are there any visible signs of a refrigerant leak, such as oil
residue?
11. Has the refrigeration system been leak checked,
evacuated and had the correctly calculated charge
weighted in?
12. Is any electrical wire laying against a hot refrigerant line?
Initial Start-Up
1. Supply power to the unit through the disconnect switch at
least 8 hours prior to starting the compressor.
2. Move the system switch on the thermostat to the AUTO or
COOL position.
3. Reduce the setting of the room thermostat to energize the
compressor.
4. Check the operation of the evaporator unit per the
manufacturer’s recommendations.
5. With an ammeter, check the compressor amps against the
unit data plate.
6. Check for refrigerant leaks.
7. Check for any abnormal noises and/or vibrations, and
make the necessary adjustments to correct fan blade(s)
touching shroud, refrigerant lines hitting on sheet metal,
etc.
8. After the unit has been operating for several minutes, shut
off the main power supply at the disconnect switch and
inspect all factory wiring connections and bolted surfaces
for tightness.
Table 9: Piping and Electrical Connection Sizes
MODEL PC090 PC120 PC180 PD180 PC240 PD240
No. Refrigeration Circuits 1 1 1 2 1 2
Suction Line OD (in.) 1 1/8 1 3/8 1 5/8 1 3/8 1 5/8 1 3/8
Liquid Line OD (in.) 5/8 7/8 7/8 5/8 7/8 7/8
Power Wiring Knockout 1 3/8 1 3/8 1 3/8 1 3/8 1 3/8 1 3/8
Control Wiring Knockout 7/8 7/8 7/8 7/8 7/8 7/8
Do not attempt to start the compressor without at least 8
hours of crankcase heat or compressor damage can
occur.