Question about pulling equity out of rental property to buy more

[Jayne Bradbury]

Hi!  I'm relatively new to Bigger Pockets but am hoping someone here can help me with my question.  

I bought a rental property a few years about and financed almost 100% of the purchase with $ from my HELOC ($150K) and a conventional mortgage ($500K). The property has appreciated $180K since we purchased it. The property didn't cash flow in a material way but the rental revenue covered the costs of both mortgages and all expenses. So, because my actual equity position was so low, my ROI was pretty huge.

I want to keep the property and buy another one. My question is whether I should pull the $180K increase in equity out of the first property (which I can do using a HELOC on the investment property) to finance the downpayment of a second property, and if I do, how to treat that in my analysis. At some point I would like to pay back that first $150K draw on my HELOC (just a personal preference to have my own house relatively unlevered).

Any ideas of how to approach this would be great.  I'm trying to get my head around it and it's not really clicking for me.  

Thanks!