IOMM AGR AGR 055A through 100A 65
Field Wiring
Interconnecting wiring for the control panel may consist of the following:
• 115 VAC power wiring
• Chilled water pump relay
• Analog input signals
• Digital input signals
• Digital output signals
• Network communications
• Communications to a personal computer
• Telephone line for remote modem access
Power Wiring
The installing contractor provides the unit voltage power source, disconnect, fuses and necessary
wiring for these circuits. All wiring must conform to the National Electrical Code and applicable
local building codes. If the control power source (120Vac) or the evaporator heater power source
(120Vac) or both are supplied from a separate external supply, remove wires 540 and 545 as
indicated on the field wiring diagram.
Power Supplies
There are several internal power supplies used by the controller and related circuitry. The regulated
5 Vdc power is supplied by the controller and provides power to all analog inputs into the ADI
board. Do not use this power supply to operate external devices. A 24 Vac power supply is
available for the alarm bell option. Wire according to the field wiring diagram.
Analog Input Signals
All sensors and transducers required for normal chiller operation are installed and wired at the
factory, All optional analog signal wiring provided by the installing contractor must be twisted,
shielded pair (Belden #8760 or equal). The optional demand limit and leaving water reset signals
are 4 to 20 milliamp DC signals. The resistive load that conditions the milliamp signal is a 249
ohm resistor mounted on the ADI board at the factory.
Digital Input Signals
Remote contacts for all digital inputs into the MicroTech controller must be dry contacts suitable for
the 24 Vac control signals from the control panel. Do not connect 120 Vac power to the digital
inputs.
Remote Stop/Start
If remote stop/start control is selected, remove the jumper between terminals #140 and #141 on TB-
7. When the remote stop/start switch is open, the controller will be in the “Off: Remote Sw” mode.
The unit will be enabled when the switch is closed.
Chilled Water Flow Switch
The chilled water flow switch is connected to field wiring terminals #142 and #143 on TB-7. When
the chilled water pump is enabled, the MicroTech controller checks for proof-of-flow through the
flow switch digital input.
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