Checking And Adjusting Refrigerant Charge; Indoor Airflow And Airflow Adjustments - Carrier Performance 48VGUK Installation Instructions Manual

48VGUK: Installation Instructions
IMPORTANT: Three-phase, scroll compressors are direction oriented.
Unit must be checked to ensure proper compressor 3-phase power lead
orientation. If not corrected within 5 minutes, 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 will be minimal.

Checking and Adjusting Refrigerant Charge

The refrigerant system is fully charged with Puron (R-410A) refrigerant
and is tested and factory sealed. Allow system to operate a minimum of
15 minutes before checking or adjusting charge.
NOTE: Adjustment of the refrigerant charge is not required unless the
unit is suspected of not having the proper Puron (R-410A) charge.
A subcooling chart is attached to the inside of the compressor access
panel. (See Table 8 and Fig. 22.) The chart includes the required liquid
line temperature at given discharge line pressures and outdoor ambient
temperatures for high stage cooling.
An accurate thermocouple- or thermistor-type thermometer, and a gauge
manifold are required when using the subcooling charging method for
evaluating the unit charge. Do not use mercury or small dial-type
thermometers because they are not adequate for this type of
measurement.
CAUTION
!
UNIT DAMAGE HAZARD
Failure to follow this caution may result in unit damage.
When evaluating the refrigerant charge, an indicated adjustment to the
specified factory charge must always be very minimal. 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.
IMPORTANT: When evaluating the refrigerant charge, an indicated
adjustment to the specified factory charge must always be very minimal.
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.
Proceed as follows:
1. Remove caps from low- and high-pressure service fittings.
2. Using hoses with valve core depressors, attach low- and
high-pressure gauge hoses to low- and high-pressure service
fittings, respectively.
3. Start unit in high stage cooling mode and let unit run until system
pressures stabilize.
4. Measure and record the following:
a. Outdoor ambient-air temperature (°F [°C] db).
b. Liquid line temperature (°F [°C]).
c. Discharge (high-side) pressure (psig).
d. Suction (low-side) pressure (psig) (for reference only).
5. Using "Subcooling Charging Charts," compare outdoor-air
temperature (°F [°C] db) with the discharge line pressure (psig) to
determine desired system operating liquid line temperature (See
Table 8).
6. Compare actual liquid line temperature with desired liquid line
temperature. Using a tolerance of ± 2°F (±1.1°C), add refrigerant if
actual temperature is more than 2°F (1.1°C) higher than proper
liquid line temperature, or remove refrigerant if actual temperature
is more than 2°F (1.1°C) lower than required liquid line
temperature.
NOTE: If the problem causing the inaccurate readings is a refrigerant
leak, refer to the Check for Refrigerant Leaks section.
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.

Indoor Airflow and Airflow Adjustments

!
UNIT OPERATION HAZARD
Failure to follow this caution may result in unit damage.
For cooling operation, the recommended airflow is 350 to 450 cfm for
each 12,000 Btuh of rated cooling capacity. For heating operation, the
airflow must produce a temperature rise that falls within the range
stamped on the unit rating plate.
NOTE: Be sure that all supply-and return-air grilles are open, free from
obstructions, and adjusted properly.
!
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury or death.
Disconnect electrical power to the unit and install lockout tag before
changing blower speed(s).
This unit has independent fan speeds for low stage cooling and high
stage cooling. In addition, 208/230 VAC models have the
field-selectable capability to run enhanced dehumidification ('DHUM')
speeds on high stage cooling and low stage cooling (as low as 320CFM
per ton). Coupled with the improved dehumidification associated with
low stage cooling, the DHUM speeds allow for a complete
dehumidification solution independent of cooling stage.
The evaporator fan motor is factory set to provide 5 different fan speeds
to choose from for the various operation modes. 208/230 VAC models
are factory-shipped with 4 speed wires connected with one spare speed
wire available.
Selection of Proper Fan Speeds for Operation Modes:
NOTE: All models are factory-shipped for nominal high stage and low
stage cooling airflow operation at minimum external static pressure.
Many models are factory-shipped for nominal high stage and/or low
stage gas heating airflow at minimum external static pressure.
(208/230 VAC models) provide airflow data for higher external static
pressures.
Gas Heating (208/230 VAC models):
each speed for a given external static pressure for high stage gas heating.
Any speed/static combination that is outside the rise range is marked
"NA" and must not be used. For single phase units only, "High" blower
speed is for high static, high stage cooling only and must not be used for
high stage gas heating speed. The unit must operate within the high stage
gas heat rise range printed on the rating plate.
Low Stage Cooling (All models): Using
airflow for low stage cooling
drops for wet coil, economizer, and filter, and add them to dry coil
measured on the system. Using this total static pressure, use
(208/230 VAC models) to find the airflows available at the total static
pressure. For 208/230 VAC models, connect the chosen fan speed wire
to "LO COOL" connection on the IGC Board (see
High Stage Cooling (All models) Using
pressure drops for wet coil, economizer, and filter, and add them to dry
coil measured on the system. Using this total static pressure, use
Table 11 (208/230 VAC models) to find the airflows available at the total
static pressure. The speed chosen must provide airflow of between 350
to 450 CFM per ton of cooling. For 208/230 VAC models, connect the
chosen fan speed wire to "HI COOL" connection on the IGC Board (See
Fig. 19).
Enhanced Dehumidification Cooling (208/230 VAC Models): Using
the total static pressure for selecting the high stage cooling speed, use
23
CAUTION
WARNING
Table 10 show the suitability of
Table 11 and the nominal
(Table 1) find the external static pressure
Fig. 19).
Table 11 find the external static
Table 11
Table 11