Installation guide

3. When using an automatic changeover room thermostat,
place both SYSTEM or MODE control and FAN mode
switches in AUTO positions. Observe that unit operates in
Cooling mode when temperature control is set to "call for
Cooling" (below room temperature), and unit operates in
Heating mode when temperature control is set to "call for
Heating" (above room temperature).
IMPORTANT: Three-phase, scroll compressors are direction
oriented. Unit nmst be checked to ensure proper compressor
3-phase power lead orientation. If not corrected within 5 nfinutes,
the internal protector will shut off the compressor. The 3-phase
power leads to the unit must be reversed to correct rotation. When
turning backwards, the difference between compressor suction and
discharge pressures may be zero.
CHECKING AND ADJUSTING REFRIGERANT
CHARGE
The refrigerant system is fully charged with R-410A refrigerant
and is tested and factory sealed.
NOTE: Adjustment of the refrigerant charge is not required unless
the unit is suspected of not having the proper R-410A charge. The
charging label and the tables shown refer to system temperatures
and pressures in Cooling mode, only. A refrigerant charging label
is attached to the outside of the service access door. If charge level
is suspect in Heating mode, reclaim all refrigerant and charge to
nameplate amount. (This information may be obtained from the
physical data table also.)
IMPORTANT: When evaluating the refrigerant charge, an
indicated adjustment to the specified factory charge nmst always be
very nfinimal. If a substantial adjustment is indicated, an abnormal
condition exists somewhere in the cooling system, such as
insufficient airflow across either coil or both coils.
REFRIGERANT CHARGE
The amount of refrigerant charge is listed on the unit nameplate
and/or the physical data table. Refer to the Refrigeration Service
Techniques Manual, Refrigerants Section.
NO CHARGE
Check for leak. Use standard evacuating techniques. After
evacuating system, weigh in the specified amount of refrigerant
(refer to system data plate).
LOW CHARGE COOLING
Use Cooling Charging Chart (Fig. 26). Vary refrigerant until the
conditions of the chart are met. Note that charging charts are
different from type normally used. Charts are based on charging
the units to correct subcooling for the various operating conditions.
Accurate pressure gauge and temperature sensing devices are
required. Connect the pressure gauge to the service port on the
suction line. Mount the temperature sensing device on the suction
line and insulate it so that the outdoor ambient does not affect the
reading. Indoor air CFM must be within the normal operating
range of the unit.
TO USE COOLING CHARGING CHARTS
Take the liquid line temperature and read the manifold pressure
gauges. Refer to the chart to deternfine what the liquid line
temperature should be.
NOTE: If the problem causing the inaccurate readings is a
refrigerant leak, refer to Check for Refrigerant Leaks section.
INDOOR AIRFLOW AND AIRFLOW ADJUST-
MENTS
PERSONAL INJURY AND UNIT DAMAGE HAZARD
Failure to follow this warning could result in personal iniury
or death and possible unit component damage.
The heating and cooling operation, the recommended airflow
is 350 to 450 cfm for each 12,000 Btuh of rated cooling
capacity. For units with optional electric heat, the airflow must
not be reduced below the levels stated in Table 2.
OUTDOOR COIL
1
LEGEND
HPS - High Pressure Switch
LCS - Loss of Charge Switch
_ [iii_Accurate¢:Meteting Device
[] Arrow indicates direction of flow
Mete_ng
Position
9
TXV in Bypass
Position
LCS
Fig. 24 - Typical Heat Pump Operation, Heating Mode
INDOOR COIL
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C03012
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