General Sequence Of Operation; Control Functions And Sequence Of Operation - Bryant Preferred 163A Installation Instructions Manual

GENERAL SEQUENCE OF OPERATION

STANDARD THERMOSTAT
Turn on power to indoor and outdoor units. Transformer is
energized.
On a call for cooling, thermostat makes circuits R- -Y and R- -G.
Circuit R- -Y energizes contactor, starting outdoor fan motor and
compressor circuit. R- -G energizes indoor unit blower relay,
starting indoor blower motor on high speed.
NOTE: To achieve the rated system performance, the indoor unit
or the thermostat must be equipped with a time delay relay
circuit.
When thermostat is satisfied, its contacts open, de- -energizing
contactor and blower relay. Compressor and motors stop. If
indoor unit is equipped with a time- -delay relay circuit, the indoor
blower will run an additional 90 sec to increase system efficiency.
CONTROL FUNCTIONS
AND SEQUENCE OF OPERATION
The outdoor unit control system has special functions. The
following is an overview of the control functions.
SEQUENCE OF OPERATION
COOLING OPERATION
This product utilizes either a standard indoor thermostat or
Evolution communication User Interface. With a call for cooling,
the outdoor fan and compressor are energized. When the cooling
demand is satisfied, the compressor and fan will shut off.
NOTE: The outdoor fan motor will continue to operate for one
minute after compressor shuts off, when the outdoor ambient is
greater than or equal to 100 degrees F.
COMMUNICATION AND STATUS FUNCTION LIGHTS
Green Communications (COMM) Light (Evolution Control
only):
A green LED (COMM light) on the outdoor board indicates
successful communication with the other system products. The
green LED will remain OFF until communications is established.
Once a valid command is received, the green LED will turn ON
continuously. If no communication is received within 2 minutes,
the LED will be turned OFF until the next valid communication.
Amber Status Light
An amber colored STATUS light is used to display the operation
mode and fault codes as specified in the troubleshooting section.
See Table 3 for codes and definitions.
NOTE: Only one fault code will be displayed on the outdoor
unit control board (the most recent, with the highest priority).
CRANKCASE HEATER OPERATION
The crankcase heater (when applicable) is energized during the
off cycle below 65 degrees F.
OUTDOOR FAN MOTOR OPERATION
The outdoor unit control energizes outdoor fan any time the
compressor is operating. The outdoor fan remains energized for
15 minutes if a pressure switch or compressor thermal protector
should open. Outdoor fan motor will continue to operate for one
minute after the compressor shuts off when the outdoor ambient
is greater than or equal to 100 degrees F.
TIME DELAYS
The unit time delays include:
S Five minute time delay to start cooling operation when
there is a call from the thermostat or user interface
(there is no bypass of this feature in a
non- -communicating system, in a communicating
system push the UI fan and up buttons simultaneously
for approximately 10 seconds)
When operating the unit with 2 wires, this delay is
S
shortened to 10 seconds.
S Five minute compressor recycle delay on return from a
brown out condition
S Two minute time delay to return to standby operation
from last valid communications (with Evolution only)
S One minute time delay of outdoor fan at termination of
cooling mode when outdoor ambient is greater than or
equal to 100 deg F
UTILITY INTERFACE
With Evolution Control
The input labeled UTIL is active only when a communicating
Evolution Control is used. This input allows a power utility
device to interrupt compressor operation during peak load
periods. See figure below for wiring connections. When the
utility sends a signal to shut the system down, the User Interface
will display "CURTAILMENT ACTIVE".
EVOLUTION BOARD
R
*
SUPPLIED BY UTILITY PROVIDER
Fig. 11 --- Utility Interface
With Non- -Communicating Thermostats
W h e n t h e u t i l i t y c u r t a i l m e n t i n t e r f a c e i s u s e d w i t h a
non- -communicating thermostat, the utility relay should be wired
in series with the Y input.
LOW AMBIENT COOLING
When this unit is required to operate below 55_F to a minimum
of 0_F outdoor temperature, provisions must be made for low
ambient operation.
Low ambient cooling operation can be accomplished two ways
depending on the control system:
S Complete Evolution System
S Standard non- -communicating thermostat
10
UTIL
*
UTILITY RELAY
UTILITY SIGNAL
OPEN RELAY
A05410