Emerson Liebert MC Microchannel Outdoor Condenser 28 - 220kW User Manual

1. Turn Off the disconnect switch on the enclosure cover.
2. Open the control enclosure cover.
3. Manually turn On the disconnect switch. Power is On and a shock hazard exists with exposure to 

hazardous voltage components.

4. If the board can still be powered up and has a display, record the parameter settings. To obtain 

parameters go to the C-- menu and press the Up or Down button to read and record the values for 

C03-09, and C27.

5. Record all of the DIP switch positions for the CANbus dip switch package. Retain these for setting 

up the new board.

6. Record positions of the jumpers for J2, J4, J5, and J6 on control board in unit. Retain these for 

set-up of new board.

7. Disconnect power from the Liebert MC Condenser unit by turning Off the main disconnect switch.
8. Use a voltmeter to check the unit and ensure that voltage is no longer present in the unit.
9. Remove the plugs and field-installed wires from the old board. Note the polarity for the CANbus 

wiring going to P49 and P50, if present.

10. Mark wires P49-1, P49-3, etc, if they are not already marked as such.
11. Remove the mechanical fasteners holding the control board in place and remove the old control 

board.

12. Install the new control board using the fasteners removed in Step 11.
13. Reattach the plugs. Reference the hot-stamps on the wire harnesses that correspond to the correct 

plug on the board. Verify that the plugs are installed properly.

14. Change the CANbus DIP switch positions so they match the old control board that is being 

removed. If the Liebert MC condenser is the second condenser on the CANbus communication 

line, set Position 1 of the CANbus DIP switch from On to Off.

15. Change the jumper positions for J2, J4, J5, and J6 to match the old control board. If the Liebert 

MC condenser is the last device on the CANbus communication line, move the jumper at J6 from 

Pins 2 and 3 to Pins 1 and 2 (see Figure 33).

16. Power up the unit.
17. Change the parameters to match the parameters from the old control board if they can be 

obtained from the old board. See Step 18 if parameters were unavailable.

18. If the old board parameters were unavailable, use the new HMI label included in kit to obtain the 

proper settings. Parameters C03, C04, C05 and C06 must be programmed with the proper EC fan 

supplier used on the unit, then address the fans (refer to 9.3 - Fan Replacement).

19. Compare the HMI label that is on the unit with the latest revision.

If there are differences, clean and dry the surface of the old HMI label; stick the new label on top 

of the old label. Completely cover the old label with the new.

20. Verify that the control board is reading pressure and temperature.
21. Verify that there are no communication alarms with the fans or the with the cooling unit the 

Liebert MC is serving.

22. Verify proper fan operation by adjusting the cooling unit that this condenser serves so that it calls 

for cooling.

Risk of arc flash and electric shock hazard. Disconnect all local and remote electric power 

supplies and wear appropriate personal protective equipment per NFPA 70E before working 

within the electric control enclosure or the fan motor connection box(es). Failure to comply can 

cause serious injury or death.
This unit contains lethal voltage. The line side of the unit disconnect switch remains 

energized when the unit disconnect switch is in the “Off” position. Use a voltmeter to verify 

that the line side input electric power to the unit disconnect switch is off before working on 

any electrical components or connections.