YORK YMC2 — VSD INITIALIZATION FAILED

The panel shows VSD INITIALIZATION FAILED when the VSD boards do not complete their power-up initialization. The manual groups this message with the cycling shutdown messages.

Each time power is applied, every board runs an initialization sequence in which memory is cleared, the program jumper positions are verified, and the serial communications links are set up. The message means the VSD boards failed that power-up initialization: the sequence did not finish, so the panel reports the fault.

• The control center and the VSD have to be energized at the same time. Pulling the fuse in the control center to take away its power creates the problem — power-up must be done by closing the main disconnect on the VSD cabinet with all fuses in place.
• A power interruption to the VSD logic board will also generate this message.
• The Eproms must be the correct version for each VSD board and must be installed correctly. They are produced as a set and cannot be interchanged between earlier and later versions.
• Serial data communications must be established. If communication between the VSD logic board and the control center does not take place during initialization, this message is generated.

1. Look at how power was last applied. The control center and the VSD must be energized together, and power-up must be made by closing the main disconnect on the VSD cabinet with all fuses in place — not by pulling the control center fuse.
2. Check whether the VSD logic board lost power at any point, since an interruption to it will produce the message.
3. Confirm that each VSD board carries the correct Eprom version and that the Eproms are installed correctly; they are made as a set and cannot be swapped between earlier and later versions.
4. Verify the serial data link: from the MOTOR screen, open the VSD DETAILS screen and read the Full Load Amps value. A zero shown for this value and the other VSD parameters points to a serial communications link problem.

The manual treats this as a cycling shutdown: the chiller will automatically restart when the cycling condition clears. After the cause is corrected, restore power the required way — close the main disconnect on the VSD cabinet with all fuses in place, so the control center and the VSD come up together.