Bryant SINGLE PACKAGED HEAT PUMP UNITS 657A - Manual (Page 17)

c. Inspect all field- and factory-wiring connections. Be sure
that connections are completed and tight.
d. Ensure electrical wiring does not contact refrigerant
tubes or sharp metal edges.
e. Inspect coil fins. If damaged during shipping and han-
dling, carefully straighten fins with a fin comb.
4. Verify the following conditions
a. Make sure that outdoor-fan blade is correctly positioned
in fan orifice. Leading edge of outdoor-fan blade should
be 2 in. back from inlet grille or 1/2–in. maximum from
the fan deck.
b. Make sure that air filter(s) is in place.
c. Make sure that condensate drain trap is filled with water
to ensure proper drainage.
d. Make sure that all tools and miscellaneous loose parts
have been removed.
5. Compressors are internally spring mounted. Do not loosen
or remove compressor hold-down bolts.
6. Each unit (system) has 2 Schrader-type ports, one low-side
fitting located on the suction line, and one high-side fitting
located on the compressor discharge line. Be sure that caps
covering these Schrader fittings are tight.
START-UP
A. CHECK FOR REFRIGERANT LEAKS
Proceed as follows to locate and repair a refrigerant leak and to
charge the unit:
1. Locate leak and make sure that refrigerant system pressure
has been relieved and reclaimed from both high- and
low-pressure ports.
2. Repair leak following accepted practices. NOTE: Install a
filter drier whenever the system has been opened for repair.
3. Add a small charge of R-22 refrigerant vapor to system and
leak-test unit.
4. Recover refrigerant from refrigerant system and evacuate to
500 microns if no additional leaks are not found.
5. Charge unit with R-22 refrigerant, using a volumetric-
charging cylinder or accurate scale. Refer to unit rating
plate for required charge. Be sure to add extra refrigerant to
compensate for internal volume of filter drier.
C99024
452 = 5 v
457 = 7 v
455 = 2 v
LEGEND
FLA — Full Load Amps
LRA — Locked Rotor Amps
MCA — Minimum Circuit Amps
MOCP — Maximum Overcurrent Protection
RLA
— Rated Load Amps
NOTES:
1. In compliance with NEC (National Electrical Code) requirements
for multimotor and combination load equipment (refer to NEC
Articles 430 and 440), the overcurrent protective device for the
unit shall be Power Supply fuse . Canadian units may be
fuse or circuit breaker.
2. Minimum wire size is based on 60 C copper wire. If other than
60 C wire is used, or if length exceeds wire length in table,
determine size from NEC.
3. Unbalanced 3-Phase Supply Voltage
Never operate a motor where a phase imbalance in supply volt-
age is greater than 2%. Use the following formula to determine
the percentage of voltage imbalance.
% Voltage imbalance
max voltage deviation from average voltage
= 100 x
average voltage
EXAMPLE: Supply voltage is 460-3-60.
AB = 452 v
BC = 464 v
AC = 455 v
452 + 464 + 455
Average Voltage =
3
1371
=
3
= 457
Determine maximum deviation from average voltage.
(AB) 457
(BC) 464
(AC) 457
Maximum deviation is 7 v.
Determine percent of voltage imbalance.
7
% Voltage Imbalance = 100 x
457
= 1.53%
This amount of phase imbalance is satisfactory as it is below the
maximum allowable 2%.
IMPORTANT: If the supply voltage phase imbalance is
more than 2%, contact your local electric utility company
immediately.
®
CKT BKR — Circuit Breaker
Fig. 23—Control-Voltage Connections
C99056
Y
C
W2
E
G
R
O
THERMOSTAT
AND SUBBASE
UNIT CONTROL POWER
SPLICE BOX
BRN
WHT
YEL
GRN
RED
ORN
—17—