34
AGZ 010B through 034B
IOMM AGZB1
Overview
The MicroTech II controller’s state-of-the-art design will not only permit the chiller to run
more efficiently, but will also simplify 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.
Release Version
This manual covers Software Release AGZ SU0102D
Operator-friendly
The MicroTech II controller’s 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 prevents unauthorized changing
of the setpoints and control parameters.
The MicroTech II controller continuously performs self-diagnostic checks, monitoring
system temperatures, pressures and protection devices, and will automatically shut down a
compressor or the entire unit should a fault occur. The cause of the shutdown will be
retained in memory and can be easily displayed in plain English for operator review. The
MicroTech II chiller controller will also retain and display the time the fault occurred. In
addition to displaying alarm diagnostics, the MicroTech II chiller controller also provides
the operator with a warning of limit (pre-alarm) conditions.
Staging
The two scroll compressors are staged on and off as a function of leaving chilled water
temperature. Lead/lag is automatic and switched every ten starts.
General Description
Compressor Motor Protection
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.
AGZ 010:
The model AGZ 010
compressor has 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:
Table 17, Fan Staging Pressures
Fan
Two-Fan Unit
Three-Fan Unit
Stage #1
On 150 psig, Off with unit
On 150 psig, Off with unit
Stage #2
On 290 psig, Off 170 psig
On 290 psig, Off 170 psig
Stage #3
--
On 310 psig, Off 180 psig
Note: Fan #1 is on with first compressor above 75
°
F (24
°
C).
Summary of Contents for AGZ 010BM
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