Bryant 3-PHASE 602A - Manual (Page 17)

E. LOW CHARGE COOLING
Use Cooling Charging Charts (Fig. 24-33). 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 superheat 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.
F. TO USE COOLING CHARGING CHARTS
Take the outdoor ambient temperature and read the suction
pressure gauge. Refer to the chart to determine what the suction
temperature should be.
NOTE: If the problem causing the inaccurate readings is a
refrigerant leak, refer to Check for Refrigerant Leaks section.
G. INDOOR AIRFLOW AND AIRFLOW ADJUSTMENTS
CAUTION: For heating and cooling operation, the rec-
ommended 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 Tables 3 and 4. Failure to maintain these
airflows could result in damage to the unit.
Tables 7 and 8 shows both heating and cooling airflows at various
external static pressures. Refer to these tables to determine the
airflow for the system being installed.
NOTE: Be sure that all supply-and return-air grilles are open, free
from obstructions, and adjusted properly.
Airflow can be changed by changing the lead connection of the
blower motor.
Unit 601A and 602A three-speed motors (except 602A030) are
factory wired for low speed operation. Unit 602A030 is factory
wired for medium speed.
For 208/230-v Motors:— 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 indoor fan motor (IFM), remove the fan
motor speed leg lead from the Time Delay Relay (TDR). This wire
is attached to TDR-3 for 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 indoor fan motor (IFM), remove fan
motor speed lead from the Time Delay Relay (TDR) and replace
with the lead for the desired blower motor speed. The motor speed
lead is attached to terminal TDR-3. For low and medium speeds,
black must be connected to the jumper wire. Insulate removed 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 connect (QC) and connect the
black lead to the BR. Insulate the jumper to avoid contact with any
chassis parts.
Fig. 22—602A Balance Point Worksheet
C00093rev2
Balance Point Worksheet
0
10
20
30
40
50
60
70
-10 0 10 17 20 30 40 47 50 60
Outdoor Air Temp (Deg F)
030
036
042
048
060
Based on Indoor Entering Air of 70 F and Rated CFM
Building Heat Loss
, 1000BTUH
Unit Integrated Heating Capacity (x1000BTUH)
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