Hey there Ryan!
I wouldn't necessarily go this route for a few reasons. There's not a lot of details, so I'm going to make some assumptions.
First off, your debt to income ratios will rise, and sooner or later, you'll run into not being able to buy more rentals. But let's assume for a moment, your numbers are correct. On a $200k house, you'd need roughly $40k for the down payment, then on top of that, closing costs, etc. Assuming you've taken all that into account, you're netting $3,600 a year, on a $40k+ investment. Around 9% COC return. That's ok, but not great in my eyes for the amount invested.
Now, that being said, if you were to use your HELOC for a property you were going to apply the BRRR method to, then by all means go for it!
Now, please don't let me discourage you from going this route. This may very well work well for you, however your rate or return is a wee low for my tastes.
Care to share more details in this deal? Are you putting money away for repairs? Do you have a property manager? Does this property need repairs anytime soon?
By all means though, an excellent question!