Refinancing heloc while under contract

[Pete B.]

We are going to be buying a new home, and renting our current primary out. I have an untapped heloc on our primary, I want to refinance to get the low introductory rate and also larger line, because of appreciation. If I refinance the untapped heloc at the same time I’m under contract and the loan is processing, will that affect my credit or debt to income ratio? Also if I tapped it to cover a low appraisal gap? Thanks