Bryant 582A Series Installation, Start-Up And Service Instructions Manual page 22

B. Checking and Adjustment Refrigerant Charge
The refrigerant system is fully charged with R-22 refriger-
ant, tested, and factory-sealed.
NOTE: Adjustment of the refrigerant charge is not required
unless the unit is suspected of not having the proper R-22
charge.
A superheat charging chart is attached to the outside of the
service access panel. The chart includes the required suction
line temperature at given suction line pressures and outdoor
ambient temperatures.
An accurate superheat, thermocouple- or thermistor-type ther-
mometer, a sling psychrometer, and a gage manifold are re-
quired when using the superheat charging method for evalu-
ating the unit charge. Do not use mercury or small dial-type
thermometers because they are not adequate for this type of
measurement.
CAUTION: When evaluating the refrigerant charge,
an indicated adjustment to the specified factory charge
must always be very minimal. If a substantial adjust-
ment is indicated, an abnormal condition exists some-
where 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 gage hoses to low- and high-pressure serv-
ice fittings, respectively.
3. Start unit in Cooling mode and let unit run until sys-
tem pressures stabilize.
4. Measure and record the following:
a. Outdoor ambient-air temperature (F db).
b. Evaporator inlet-air temperature (F wb).
c. Suction-tube temperature (F) at low-side service
fitting.
d. Suction (low-side) pressure (psig).
5. Using ''Cooling Charging Charts'' compare outdoor-air
temperature (F db) with the suction line pressure (psig)
to determine desired system operating suction line tem-
perature. See Fig. 18-30.
6. Compare actual suction-tube temperature with desired
suction-tube temperature. Using a tolerance of ±3° F, add
refrigerant if actual temperature is more than 3° F higher
than proper suction-tube temperature, or remove refrig-
erant if actual temperature is more than 3° F lower than
required suction-tube temperature.
NOTE: If the problem causing the inaccurate readings is a
refrigerant leak, refer to Check for Refrigerant Leaks section
on page 15.
C. Indoor Airflow and Airflow Adjustments
CAUTION: 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.
Table 7 shows the temperature rise at various airflow rates.
Tables 9 and 10 show both heating and cooling airflows at
various external static pressures. Refer to these tables to de-
termine the airflow for the system being installed. See
Tables 11A and 11B for wet coil pressure drop.
NOTE: Be sure that all supply- and return-air grilles are open,
free from obstructions, and adjusted properly.
WARNING: Shut off gas supply then disconnect elec-
trical power to the unit before changing blower speed.
Electrical shock can cause personal injury or death.
Airflow can be changed by changing the lead connections of
the blower motor.
Unit 582A two- or three-speed motors (except size 030) are
factory wired for low speed operation. Unit 582A030 is fac-
tory wired for medium speed.
All 583A units are factory wired for low speed and may need
to be wired for medium or high speed in the field.
For 208/230-v
The motor leads are color-coded as follows:
3-SPEED
black = high speed
blue = medium speed
red = low speed
To change the speed of the blower motor (BM), remove the
fan motor speed leg lead from the blower relay (BR). This
wire is attached to terminal BM for single-phase and 3-phase
units. To change the speed, remove and replace with lead for
desired blower motor speed. Insulate the removed lead to avoid
contact with chassis parts.
For 460-v GE Motors
The motor leads are color coded as follows:
3-SPEED
black = high
violet = jumper
orange = medium
red = low
To change the speed of the blower motor (BM), remove fan
motor speed lead from the blower relay (BR) and replace with
the lead for the desired blower motor speed. The motor speed
lead is attached to terminal BM. For low and medium speeds
black must be connected to the jumper wire. Insulate re-
moved lead end to avoid contact with chassis parts. To select
high speed on 460-v GE motors, separate the black (female
quick connect [QC]) from the jumper lead (male quick con-
nect [QC]) and connect the black lead to the BR. Insulate the
jumper to avoid contact with any chassis parts.
—22—
2-SPEED
black = high speed
red = low speed
2-SPEED
black = high
blue = jumper
red = low