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FIGURE 12
1
2
INDOOR COIL
STAGE 2
INDOOR COIL
STAGE 1
OUTDOOR COIL
STAGE 2
OUTDOOR COIL
STAGE 1
OUTDOOR
FAN 1
OUTDOOR
FAN 2
B4
B5
REFRIGERANT STAGES - 078, 092, 102
(BOTH FANS ARE ENERGIZED IN LOW SPEED WITH A
Y1 DEMAND AND HIGH SPEED WITH A Y2 DEMAND)
FIGURE 13
REFRIGERANT STAGES - 122, 150
1
2
INDOOR COIL
STAGE 2
INDOOR COIL
STAGE 1
OUTDOOR COIL
STAGE 2
OUTDOOR COIL
STAGE 1
OUTDOOR
FAN 1
OUTDOOR
FAN 2
B4
B5
B21
OUTDOOR
FAN 3
(ALL FANS ARE ENERGIZED IN LOW SPEED WITH A
Y1 DEMAND AND HIGH SPEED WITH A Y2 DEMAND)
IV- SYSTEMS SERVICE CHECKS
WARNING
Refrigerant can be harmful if it is inhaled. Refrigerant
must be used and recovered responsibly.
Failure to follow this warning may result in personal
injury or death.
A-Charging
WARNING-Do not exceed nameplate charge under any
condition.
This unit is factory charged and should require no further
adjustment. If the system requires additional refrigerant,
reclaim the charge,
evacuate the system, and add required
nameplate charge.
NOTE - System charging is not recommended below 60°F
(15°C). In temperatures below 60°F (15°C) , the charge
must be weighed into the system.
If weighing facilities are not available, or to check the
charge, use the following procedure:
1-
Attach gauge manifolds to discharge and suction lines. With
the economizer disabled, operate the unit in cooling mode
at high speed using the following mobile service app menu
path:
SERVICE > COMPONENT TEST > COOLING >
COOLING STAGE 3
2- Use a thermometer to accurately measure the outdoor
ambient temperature.
3- Apply the outdoor temperature to tables 3 through 7 to
determine normal operating pressures. Pressures are
listed for sea level applications at 80
5F dry bulb and
67
5F wet bulb return air.
4- Compare the normal operating pressures to the pres
sures obtained from the gauges. Minor variations in
these pressures may be expected due to differences
in installations. Significant differences could mean that
the system is not properly charged or that a problem
exists with some component in the system. Correct
any system problems before proceeding.
5- If discharge pressure is high, remove refrigerant from
the system. If discharge pressure is low, add refriger
ant to the system.
S Add or remove charge in increments.
S Allow the system to stabilize each time refrigerant
is added or removed.
6- Use the following subcooling method along with the
normal operating pressures to confirm readings.
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