Unit installation

26 ACZ 010A through 039A IOMM ACZ1-2
Overview
The MicroTech II controller's state-of-the-art design will not only permit the unit to run
more efficiently but also simplifies troubleshooting if a system failure occurs. Every
MicroTech II controller is programmed and tested prior to shipment to contribute to a
trouble-free start-up.
Software Version
This manual is based on software version ACZSU0102A
Operator-friendly
The MicroTech II controller menu structure is separated into three distinct categories,
which provide the operator or service technician with a full description of current unit
status, control parameters, and alarms. Security protection deters unauthorized changing of
the setpoints and control parameters.
MicroTech II control continuously performs self-diagnostic checks, monitoring system
temperatures, pressures and protection devices, and will automatically shut down a
compressor or the entire unit if a fault occurs. The cause of the shutdown will be retained
in memory and can be easily displayed in plain English for operator review. The
MicroTech II controller will also retain and display the time the fault occurred. In addition
to displaying alarm diagnostics, the MicroTech II controller also provides the operator with
a warning of limit (pre-alarm) conditions.
Staging
The two scroll compressors are staged on and off by contact closure of the field supplied
remote two-stage staging thermostat. Lead/lag is automatic and switched every ten starts.
General Description
NOTE: When the following descriptions refer to "evaporator pressure", the pressure is
actually the suction pressure within the condensing unit itself.
Compressor Motor Protection
ACZ 016 – 039: The solid-state compressor motor protector module incorporates a 2-
minute “time-off” relay utilizing the bleed-down capacitor principle. Any time the
protection system opens or power to the module is interrupted, the 2-minute “time-off”
delay is triggered and the module will not reset for two minutes. Once the 2-minute period
has passed the motor protector contacts M1 and M2 reset, provided the protection system is
satisfied and power is applied to the module.
Note: If the power circuit is broken once the 2-minute period is passed, the pilot
circuit will reset without delay when power is reapplied.
ACZ 010 - 013: The model ACZ 010 and ACZ 013 compressors have internal line
breakage with automatic reset.
FanTrol Head Pressure Control
FanTrol is the standard method of head pressure control that automatically cycles the
condenser fan motors in response to condenser pressure. This function is controlled by the
microprocessor, maintains head pressure and allows the unit to run at low ambient air
temperatures down to 35°F (1.7°C). Fans are staged as follows: