Bryant Evolution Extreme 191VAN - Step 13 - System Functions and Major Components; Primary Control Module

191VAN Evolution™ Extreme Variable Speed Air Conditioner: Installation Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
14
Step 13 – System Functions and Major Components
The 191VAN models utilize an Evolution™ Connex™ System Control.
When a demand for cooling exists, the Evolution™ Connex™ System
Control will direct the outdoor unit to operate at the minimum required
speed to satisfy demand. When a call for cooling is made, the outdoor
fan is first energized, followed shortly by the compressor, where they
will both operate at a start speed for a brief period.
Once certain start criteria are met, the compressor and fan will ramp to
the target demand speeds. If continued operation at the initial speed does
not satisfy demand, the system will ramp up in 60 RPM increments until
it satisfies the demand. After the higher demand is met, the unit will
modulate capacity such that demand is met and indoor conditions are
maintained.. Ideal performance is achieved when system operates
continuously at the lowest speed possible, minimizing variation in
conditioned space temperatures while using minimal power.
As the unit operates at lower capacity, system vapor (suction) pressure
will be higher than it is during a standard single-stage system operation
or during a higher capacity operation.
When all demand is satisfied, the compressor will shut off. An internal
pressure equalization valve will energize during the off-cycle to allow
for easy start up at the next call for cooling.
The Evolution™ Connex™ System Control displays the operation mode
and fault codes as specified in the troubleshooting section. See Table 11
for codes and definitions.
NOTE: The latest codes are stored and can be accessed via the
Evolution™ Connex™ System Control.
Primary Control Module
The Primary Control Module (PCM) controls the various functions of
the outdoor unit. The PCM has the following outputs:
1. VFD Modbus Communication (VFD COMMS)
2. VFD Low-voltage relay control
3. Pressure Equalization Valve (PEV)
4. Liquid Line Solenoid (LLS)
The PCM has the following inputs:
1. Outdoor Discharge Line Temperature (ODT)
2. Outdoor Ambient Temperature (OAT)
3. Liquid Line Temperature (LLT - AC)
4. Outdoor Suction Temperature (OST)
5. Discharge & suction pressure transducers (DPT & SPT). Labeled as
P1 & P2 on the PCM
6. Service Interface communication port (SERVICE PORT)
7. CCN communication
8. Model plug
9. 24VAC input power
The PCM receives a cooling demand from the Evolution™ Connex™
System Control and determines the appropriate compressor, fan, PEV,
and LLS action based upon the various sensor inputs.