I have a customer who wanted a home equity loan to puchase a tractor. I explained the process and timeline and they wanted to purchase the tractor sooner than I could fund the loan. They have a home equity line of credit that they recently paid the balance down to zero, so I suggested they advance on the HELOC to aquire the tractor. They eventually want a fixed rate/fixed payment on the tractor loan (secured by their home) and wanted to have the HELOC available for other uses, so I told them we will now do a home equity installment loan for them and pay the HELOC balance back down to zero and leave it open. If we are paying down a HELOC to zero with a home equity installment loan(both secured with the borrower's home), but leaving it open, is this a refinance for HMDA purposes?

No. It does not meet the difinition: "satisfies and replaces an existing obligation by the same borrower". The HELOC obligation remains.