Why this is harder than it sounds
A home equity line of credit on the house you live in is an ordinary product. Ask for a HELOC on an investment property and the answer changes. Many lenders that advertise equity lines exclude investment property entirely, and the rest treat it more cautiously than an owner-occupied home.
The reason is risk. When money is tight, people keep paying on the home they live in and let a rental slip first. A line secured by an investment property carries more of that risk, and lenders limit it accordingly.