Johnson Controls PC090 THRU 240 Manuale Utente

430645-YIM-D-0610

Johnson Controls Unitary Products

17

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.

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.

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?

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.

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Do not attempt to start the compressor without at least 8 
hours of crankcase heat or compressor damage can 
occur.