Understanding a Refinance

[Brett B.]

I am going to look at a duplex this week for my first potential investment property and want to make sure I understand everything correctly. 

I used the BP rental property calculator and at the current asking price of $189,000 and using 7% for repairs, capex, and vacancy, it will cash flow $493 per month. Using the 50% rule shows $319 per month. 13.83% COC return.

I have a HELOC on my primary residence for $50,000, which I did not factor the payments into my cash flow calculations. Is this correct?

I am a little unclear about how a refinance will work and effect my mortgage/cash flow. I am able to put down 20-25%, depending what the lender requires. How does the refinance process work with only that much equity in the property? Can I cash that out after 6 months and repay my HELOC entirely?

Thanks in advance!