CAS MSC Troubleshooting - Local Control

CAS MSC Troubleshooting - Local Control

The following instructions detail how to troubleshoot the CAS MSC to make sure it is providing DC Voltage output to the motor.

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Checking Power to the Fan and MSC.

1. Make sure there is proper voltage to the fan and make sure the fan disconnect is in the ON position.
2. Check the MSC display to make sure it is illuminated and displaying information.
  1. If the MSC display is not illuminated, check for 24 VAC on the load side of the step down transformer.
  2. If voltage is present on the load side of the transformer, check across 24 VAC and C on the back of the MSC.
3. If no voltage is present, confirm that the correct line voltage is present at the line side of the step down transformer.
  1. If the correct voltage is present, wiring is correct, and there is no display, replace the MSC.
Notes
MSC shown with wiring removed.

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Checking the CAS MSC Configuration Settings

1. Once power is confirmed, press the MENU button to access the configuration menu. You should see BOARD CONFIG (1).
  1. Press ENTER and you will be prompted to enter the password (2). Using the UP and ENTER buttons, enter 0225 as the password (3).

2. Once the password is correct, press ENTER. You will want to make sure the MSC settings are correct before proceeding.
  1. MOTOR TYPE (4), CONTROL TYPE (5), and SPEED SETTINGS (6) are the main settings to confirm.

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Troubleshooting

Once settings are confirmed, proceed with the troubleshooting information below.
  1. These steps are for CONTROL TYPE = LOCAL.
1. Unplug the black 4-pin connector from the back of the MSC. Change the SET SPEED % to 50%. Using a multi-meter set to DC Volts, check across the 2 pins where the red and yellow wires would plug into the MSC. At 50%, the DC Volts reading should be around 12 VDC.
2. If the output at 50% is correct, change the SET SPEED % to 100% and again, check DC Volts across the pins where the red and yellow wires would plug into the MSC. At 100%, the DC Volts should be around 24 VDC.
3. If both readings are correct, the issue is likely internal of the motor. If the voltage readings DO NOT correlate with the speed % settings, the issue is likely with the MSC.

Notes
MSC shown with wiring removed.