As has been said several times in the string above, transactions to or from a HELOC cannot be subject to Regulation E because a HELOC is not a consumer asset account.
So, if a check from a HELOC is converted, it's subject to NACHA rules but not subject to Reg. E. It will, of course, be subject to Regulation Z.
John S. Burnett
Fighting for Compliance since 1976
Bankers' Threads User #8