You might see it referred to as "cash on cash".  

No references for you - sorry.

Does anybody here has someone that you have worked with and feel comfortable referring? 

Agents that aren't in that area will be eager to refer you to agents that are.

I also have CPAs that I work with regularly and I’m happy to refer you their way.

I would put heavy emphasis into how you pre-qualify your potential tenants (credit checks, income verification, past reference checks, etc) and you'll be fine. 

The easier option is just to bill back the prorated portion of water/sewer bill to tenant, which is referred to as RUBS.

Then call the local burnham or any boiler rep, or supply house and ask them to cross reference your boiler with an equivalent replacement gas boiler.

Must have references and pictures. 

You also read through your lease and see if there is anything in there that would could reference to help, but I'll say it's a unique situation that you may not find much help in your lease on.