91
3
JOHNSON CONTROLS
5276178-JIM-C-0118
SECTION 3 – START-UP
To protect warranty, this equipment
must be installed and serviced by an
authorized Johnson Controls service
mechanic or a qualified service person
experienced in air handling and con
-
denser unit installation. Installation
must comply with all applicable codes,
particularly in regard to electrical
wiring and other safety elements such
as relief valves, HP cut-out settings,
design working pressures and venti
-
lation requirements consistent with
the amount and type of refrigerant
charge.
Lethal voltages exist within the Con
-
trol Panel. Before servicing, open and
tag all disconnect switches.
Reference publication Form 100.50-
SU4 “Quick Start-up Guide” for ad
-
ditional information.
CRANKCASE HEATERS
With power applied to the rooftop unit, the crankcase
heater for each compressor will be ON whenever the
compressor is not running. The heater is interlocked into
the compressor motor contactor and is not controlled
by the microprocessor.
The purpose of the crankcase heater is to prevent
the migration of refrigerant to the crankcase during
shutdown, assuring proper lubrication of the compressor
on start-up.
Anytime power is removed from the unit for more than
an hour, the crankcase heater should be left ON for 24
hours prior to start.
Power must be applied to the rooftop
unit 24 hours prior to starting the unit
compressors. Failure to observe this
requirement can lead to compressor
damage and voiding of the compressor
warranty.
CHECKING THE SYSTEM PRIOR TO INITIAL
START (NO POWER)
Unit Checks
1. Inspect the unit for shipping or installation dam-
age.
2. Visually check for refrigerant piping leaks.
3. The compressor oil level should be maintained so
that an oil level is visible in the sight glass. The
oil level can only be tested when the compressor is
running in stabilized conditions, guaranteeing that
there is no liquid refrigerant in the lower shell of the
compressor. In this case, the oil must be between
1/4 and 3/4 in the sight glass. At shutdown, the oil
level can fall to the bottom limit of the oil sight
glass.
4. Check the control panel to assure it is free of for-
eign material (wires, metal chips, etc.).
5. Visually inspect field wiring (power and control).
Wiring MUST meet N.E.C. and local codes.
6. Check tightness of terminal lugs inside the power
panel on both sides of the contactors, overloads,
fuses, and power connections.
7. Verify fuse sizing in main circuits.
8. Verify field wiring for thermostat (if applicable),
optional zone sensor, etc.
9. Verify all applicable pneumatic tubing has been
field installed for duct static pressure transducers
(VAV units), optional building pressure transducer
for power exhaust option, and outdoor static pres-
sure prove.
10. Check Blower Bearing Set Screws
The bearing set screws on the supply air blower
are properly torqued before shipment. However,
in transit they may loosen. Prior to start-up, they
should be rechecked. The set screws are 3/8" and
the torque range is between 200 and 215 in.-lbs.
If a unit is equipped with exhaust
fans, those bearing set screws should
also be rechecked. The set screws are
1/4" and the torque is between 70 and
87 in.-lbs.
11. Verify proper drive alignment of supply and
exhaust fans
(refer to
“
Maintenance
”
section of
manual).
Summary of Contents for 40 25 TON
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