There are only two possible scenarios for sending a BPR02 equal to ‘0’.
The first scenario would be when the payment amount is zero, but it is not a pre-notification. In this case, the BPR01 must be ‘H’ (“Use this code when the actual provider payment (BPR02) is zero and the transaction is not being used for prenotification of Future Transfers. This indicates remittance information without any associated payment.”) and the BPR04 must be ‘NON’ (“Use this code when the Transaction Handling Code (BPR01) is H, indicating that this is information only and no dollars are to be moved.”)

The second scenario would be a Prenotifcation. For a Prenotification the BPR01 must be ‘P’ (“This code is used only by the payer and the banking system to initially validate account numbers before beginning an EFT relationship. Contact your VAB for additional information.”) and the BPR04 may be ‘ACH’ because the code note reads in part, “Use this code to move money electronically through the ACH, or to notify the provider that an ACH transfer was requested”.

Any usage of BPR04 equals ‘ACH’, and the BPR02 is ‘0’ when the transaction is not a prenotification is not compliant with the 005010X221A1 TR3. It still may not make business sense to send an 835 for a prenotifcation transaction, but it would be compliant with the TR3.