Problem:
UC400 Low airflow - supply fan failure diagnostic
Resolution:
This diagnostic is generated when the ECM send the controller specific diagnostic codes. See: ECM IMC Diagnostic and Fan Codes for UC400B, Symbio 400B and Symbio 500. This diagnostic is typically caused by an incorrect ECM board configuration that does not match the actual unit configuration. Often there is a speed parameter configured for motor 2 on a unit that only has one fan motor (ALM2 and AhM2). Check each parameter of the ECM board configuration against the nameplate on the unit. If all configuration parameters match the name plate, and the diagnostic is still present after a power cycle, proceed to the steps below. See UNT-SVX19 for ECM engine module configuration help.
1. Direct USB connect with Tracer TU.
2. Navigate to the Status Utility/Controller Status page. Take a screen shot of the unit tag information, serial number, model number, and sales order number. These can be manually restored by clinking the edit button near the top right after the new configuration is loaded.
3. Navigate to the Equipment Utility/Configuration page. Take screen shots of each configuration selection on the page.
4. Navigate to the Equipment Utility/Setup parameters page. Verify and record stroke times for all valves.
5. If you have any custom TGP2 programs, open the TGP2 editor, open the program, compile and save a copy. You may also need to re-create any custom points associated with these programs after clearing and rebuilding controller. All factory programs and points will automatically be restored when the new configuration is loaded.
6. Navigate to the Status Utility/Controller Settings page. Record the Controller name. From the protocol group, verify and record the software device ID, protocol selection (MS/TP or ZigBee) and Controller units. The device ID and protocol selection will not be cleared, but they should be checked after clearing the controller.
7. Click the Clear Controller button. Once the controller is cleared, enter the controller name, select controller units, and send to device.
8. Configure the blue ECM board:
Change EhPt to "OFF".
Configure the ECM board to the factory settings that are on a white sticker located inside the control box next to the blue ECM board. If the setting are not listed on the sticker, call technical service with the serial number to request a unit specific settings list. If
Note: Once configuration of the ECM board is complete, change EhPt to "ON".
9. Navigate to the TU Equipment Utility/Configuration page. From your screen shots, make the correct selections, then send to device. Wait until you see Configuration Saved Successfully at the bottom of the screen before proceeding.
If you cleared the controller without making screen shots of the configuration selections, the configuration can be restored by doing a model number lookup on the controls tech webpage, then making the correct selections based on model number in the TU Equipment/Configuration page.
10. If you have any custom points or TGP2 programs, re-load or recreate them now.
11. If you have an Air-Fi zone sensor, you may need to press the center button twice for re-associate it with the UC400. If there is an error code on the sensor screen, see
Other things to consider: Check all connections on the IMC link, check all connections from board to board, check wiring connections from the red (adapter board) to the motor. See the attached ECM troubleshooting guide for more information.
Notes:
Applies to UC400 controller.
Other Question/Problem/Cause Statements:
- Low airflow- Supply fan failure?
- UC-400 diagnostic Supply fan failure
- ECM board UC400 board diagnostic