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4. Tighten setscrews and replace condenser-fan assembly.
5. Turn on power to unit.
Verify Sensor Performance
Verify that thermistor, transducer, and switch inputs are reading
correctly. These values can be accessed through the Scrolling
Marquee display in the Temperatures, Pressures, and Inputs
menus. Some values will depend on configuration choices. Refer
to the Control Set Up Checklist completed for the specific unit
installation and to the configuration tables in the Basic Control
Usage section.
Economizer Operation During Power Failure
Dampers have a spring return. In event of power failure, dampers
will return to fully closed position until power is restored.
Do not
manually operate damper motor.
MOUNTING
BASE
FAN
PULLEY
MOTOR
PULLEY
SLIDE-OUT
FAN DECK
SCREW
SCREW
(HIDDEN)
MOTOR
FAN DECK STOP
C06177
Fig. 43
---
Evaporator--Fan Motor Adjustment
C06041
Fig. 44
---
Evaporator--Fan Alignment and Adjustment
C06180
Fig. 45
---
Condenser--Fan Adjustment
Evacuation
Proper evacuation of the system will remove noncondensables
and ensure a tight, dry system before charging. Evacuate from
both high and low side ports. Never use the system compressor as
a vacuum pump. Refrigerant tubes and indoor coil should be
evacuated to 500 microns. Always break a vacuum with dry
nitrogen. The two possible methods are the deep vacuum method
and the triple evacuation method.
Deep Vacuun Method
The deep vacuum method requires a vacuum pump capable of
pulling a minimum vacuum of 500 microns and a vacuum gauge
capable of accurately measuring this vacuum depth. The deep
vacuum method is the most positive way of assuring a system is
free of air and liquid water. (See Fig. 46.)
LEAK IN
SYSTEM
VACUUM TIGHT
TOO WET
TIGHT
DRY SYSTEM
0
1
2
3
4
5
6
7
MINUTES
5000
4500
4000
3500
3000
2500
2000
1500
1000
500
MICRONS
C06264
Fig. 46
---
Deep Vacuum Graph
Triple Evacuation Method
The triple evacuation method should only be used when vacuum
pump is capable of pumping down to 28 in. of mercury and
system does not contain any liquid water. Proceed as follows:
1. Pump system down to 28 in. of mercury and allow pump
to continue operating for an additional 15 minutes.
2. Close service valves and shut off vacuum pump.
3. Connect a nitrogen cylinder and regulator to system and
open until system pressure is 2 psig.
4. Close service valve and allow system to stand for 1 hr.
During this time, dry nitrogen will be able to diffuse
throughout the system, absorbing moisture.
5. Repeat this procedure. System will then contain minimal
amounts of contaminants and water vapor.
48/
50P
G
C
03
--
16