If the oil runs out and results in damage to the system, the tenant will pay for the repair.I also recommend you be clear about this in your written lease for future renters.If there are repeated violations, terminate their lease and start with a new renter.

I'm hesitant because I don't want to be on the hook if in the future something goes wrong like the buyer stops making payments.

Just know that rates in general are high right now, and if you can negotiate a way to get a lower rate in the future without having to refinance with your seller, that would be a good thing.  

However, we do plan to pull out the equity in the near future.

Best of luck to you there, I hope you are able to double your rents in the near future and your property values go to the moon. 

Clearly there were missed maintenance issues in this case, but I would still instruct your PM (or future PM) to make it a requirement that all prospective tenants tour your properties first before processing applications.I’ve even had tenants sign Sight Unseen / As-Is addendums and later be unhappy and still want to break their leases.

Last, think about what you see for your business and your life in the future.

This was an appreciation play with hopefully a cash out refi in the future but who knows when that will happen. 

It also creates evidence of their "incompetence" for others to find if they go looking (think future clients).  

Quote from @Cali Skier: I agree with Mike that you should be fine.I recommend you tighten your standards for future renters.1.