Carrier Infinity 26VNA1 Installation Instructions Manual page 14

26VNA1 Infinity® Variable Speed Air Conditioner: Installation Instructions
Step 13 – System Functions and Major Components
The 26VNA1 models utilize an Infinity® System Control. When a
demand for cooling exists, the Infinity® 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 Infinity® System Control displays the operation mode and fault
codes as specified in the troubleshooting section. See
and definitions.
NOTE: The latest codes are stored and can be accessed via the Infinity®
System Control.
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
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 Infinity® System Control
and determines the appropriate compressor, fan, PEV, and LLS action
Table 11 for codes
based upon the various sensor inputs.
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