5012886-YIM-B-0517
Johnson Controls Unitary Products
17
Figure 10: 40 & 50 Ton Piping Connections
Piping And Electrical Connections
Piping connections are made from the rear of units.
Connections can be made directly to the suction and liquid line
service valves. Piping can be routed to the units from the left or
right side.
Electrical connections for power and control wiring are made
from the front of all units, left of the electrical control box
access. See Tables 7 & 8 and Figures 7 thru 10 and for piping
sizes and electrical knockout details.
Start-Up
Crankcase Heater
The crankcase heater must be energized at least 8 hours
before starting the compressor. To energize the crankcase
heater, 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 hold-down nuts 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 refrigerant 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.
Liquid (Sys 2)
Suction (Sys 2)
Suction (Sys 1)
Liquid (Sys 1)
10.974
57.689
11.385
37.731
41.934
46.206
50.409
88.140
Do not attempt to start the compressor without at least 8
hours of crankcase heat or compressor damage can
occur.
