McQuay 4AC20C / M4AC020C, Installation Manual

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English
1. Handset location
The handset is located in the terminal box behind the service panel.
2. LED Display (microprocessor board)
The keypad LED will light up when the unit is powered up.
The LCD will light up when the unit is turned on.
3. LCD display (controller handset)
During normal operations, the LCD can display the entering water temperature, the leaving water temperature, the enter-
ing water setpoint temperature, compressor on or off status and outdoor air temperature. When malfunctioning occurred,
the LCD would blink. The display would show the faulty parameter and the date and time of the occurrence.
4. Controller functioning specification
There is a 3 minute delay for the compressor and fan motor to restart (default setting).
CONTROL OPERATION GUIDE
The unit is equipped with a microprocessor controller board. The microprocessor controller is provided to give temperature
control for the system by accurately measuring and controlling the water entering and water leaving temperature. The tem-
perature setting in the unit is preset in the factory. It is not recommended to change the setting unless necessary. A wired
controller handset is connected to the microprocessor board. Every parameter setting and reading can be observed from the
LCD of the handset.
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CAUTION
• Use the controller handset to switch on / off the unit. Do not plug off the main power supply directly, it would cause
the unit to breakdown.
• Do not change the settings of the safety devices.
• Installation
When fastening the LCD panel to the bracket,
Step 1 Step 2
Hook the LCD panel
from the top first
Push to fasten the LCD
panel to the bracket