Startup (cooling)
Prestart checklist
After installation has been completed, make the following checks:
1. Check the electrical supply voltage. Ensure that it is the same as listed on the unit nameplate.
2. Set the room thermostat to the OFF position.
3. Turn ON the unit electrical power.
4. Set the room thermostat fan switch to ON.
5. Check the indoor blower rotation.
6. Check the blower drive belt tension.
7. Check the unit's supply air (CFM).
8. Measure the evaporator fan motor's amp draw.
9. Set the room thermostat fan switch to OFF.
10. Turn the electrical power OFF.
Operating instructions
1. Turn the unit's electrical power ON.
2. Set the room thermostat to lower than the room temperature.
3. After the built-in time delay (5 minutes), the first stage compressors energize.
Post start checklist
1. Verify the proper system pressures.
2. Measure the temperature drop across the evaporator coil.
Microprocessor controller
Units come with the state of the art Smart Equipment control (SEC) system. All units are factory
commissioned, configured, and run tested. The SEC can be configured to use with a standard
thermostat, a zone sensor, or to communicate with the field controller (FC) bus using BACnet® MS/
TP, Modbus™ or N2 protocols.
Temperature sensors
Each unit comes with standard supply air temperature (SAT) and return air temperature (RAT)
sensors. The outside air temperature (OAT) is provided with the airside economizer option. All
sensors are field wired and installed.
USB port
The controller comes with a long list of features including data logging, current and previous
system faults, and software update capabilities using the onboard USB port and a common flash
drive. Energy use monitoring capabilities allow custom tailoring. This allows a system to work more
efficiently at all times and occupancy levels. Self-test and startup reports are also available from the
board through the USB port.
LCD display
The board has an easy to read, built-in LCD display and easy to use buttons and a navigation
joystick. These features allow the user to quickly navigate the menus that display the unit status,
options, current function, supply, return and outdoor temperatures, fault codes, and other
information.
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Model DSH024C–120C Horizontal R-410A Air Conditioning Units C-Generation Smart Equipment Controller
Johnson Controls
