Speed Control - Bryant 598A Series D Installation And Start-Up Instructions Manual

HIGH VOLTAGE
L2 LO HI CCH ODF
O C
K1 K2 K3 K4 K5 K6
LED 1
Fig. 9—LED and Potentiometer Location
70
60
50
40
30
20
10
50 60 70
TEMPERATURE (°F)
Fig. 10—Typical Cooling Balance Points
J. Compressor PTC Overload Protection
The control senses the resistance of the compressor internal
positive temperature coefficient (PTC) overloads. If PTC resis-
tance is out of range, control shuts off the unit until resistance
range is acceptable. See Table 8 for compressor PTC ranges.
TABLE 8—COMPRESSOR PTC RANGES
COMPRESSOR INTERNAL PTC RESISTANCE
Safe range (77°F)
To trip
To reset
When the control turns outdoor unit off due to out of range PTCs,
the unit remains off for 15 minutes with outdoor fan running. After
15 minutes, the control checks resistance every 5 minutes until it
reaches the reset range. During this time, a malfunction signal
appears at control board. If a PTC trip occurs 3 times, the control
locks out outdoor unit operation and provides a malfunction signal
at control and indoor thermostat.
K. Pressure Switch Protection
The outdoor unit is equipped with high- and low-pressure
switches, wired in series. If the control senses the opening of a
pressure switch, it provides a 5-minute time delay in outdoor unit
operation with outdoor fan running. A malfunction signal appears
on control when pressure switch opens. If pressure switch remains
open for 1 hr or longer, a malfunction signal is provided at L
terminal on indoor thermostat.
LOW VOLTAGE
LM1 LM2 DFT1 DFT2 T1 T2 S2 S1 PW2 PW1
1 P1 18
K7
SPEED-UP
STAGE 2 DEFROST BALANCE
LATCH TIME POINT
A91503
HIGH SPEED
BALANCE POINT
STRUCTURE
BALANCE POINT
LOW SPEED
BALANCE POINT
80 90 100 110 120
A91282
1.5k to 7.8k ohms
26k to 34k ohms
8.4k to 10k ohms
WARNING: Interlocked contactor coils are 240v, high
voltage. Electrical shock can cause personal injury or
death.
CAUTION: Do not bypass interlocks of contactors, as
compressor damage will occur.
L. Major Components

2-SPEED CONTROL

The 2-speed control board controls the following functions:
- High- and low-compressor contactor operation
- Outdoor fan motor operation
- Crankcase heater operation
- Compressor protection
- Pressure switch monitoring
- Second-stage latching
- Time delays
- 5-minute time delay speed-up (bypass)
Refer to the System Functions section for individual function
information.
HEADER PIN HOUSING
The header pin housing is the plastic assembly which holds the
stripped lead ends for field connections. The 2-speed control
receives 24-vac low-voltage control system inputs through the
housing/pins. The housing also contains jumpers which the control
uses for system configuration, such as heat pump versus air
conditioner. Refer to Fig. 11 for header pin housing configuration.
2-SPEED COMPRESSOR
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
Fig. 11—Header Pin Housing Configuration
The 2-speed compressor contains motor windings that provide
low-speed, 4 pole (1750 RPM) and high-speed, 2-pole (3500
RPM) operation. Refer to Table 9 for appropriate winding resis-
tances. Refer to unit wiring label for winding configurations.
The 2-speed compressor is protected by an internal pressure relief
(IPR) which relieves discharge gas into compressor shell when
differential between suction and discharge pressures exceeds 500
psi.
The compressor is also protected by 3 PTC devices attached to
motor windings. The PTC resistance is sensed by the 2-speed
control. See Table 8 for resistance ranges.
—15—
C - TRANSFORMER COMMON
R - TRANSFORMER LINE
Y2 - SECOND STAGE COOLING
Y1 - FIRST STAGE COOLING
L - MALFUNCTION LIGHT
A93565