So, installing them outside or in a corrosive environment will shorten their lifespan.Regarding the relief valves...When water is heated, it expands.

Should I raise the rents and pay the heat bill myself?

These are the elements to winning in a competitive market.   

Also make sure if it was newly renovated they didn't lipstick the property with carpet,paint, replace door knobs etc.You want big items like heating,a/c, roof, plumbing, electrical,etc. to have a lot of life left on them.If you buy based on inflated rents and then have flat to depressed rent in coming years, higher turnover and make ready costs, and high capital costs for large ticket items you could lose a bunch of money.Make sure the property insurance policy is not a master one insuring multiple properties as the owners policy could be low in cost compared to what you will pay.

He got himself on the HOA board, started enforcing rules, removed the bad elements and his investment paid off huge.It took him a lot of work and several years.

Hi Bill,If you are looking for conventional loans in your name, Elements Financial in Indy has great rates/terms for the SFR and Duplex.

A clear floor plan with the exits and safety elements are what is needed.  

For example, I am looking at https://www.redfin.com/IL/Chicago/3313-W-Cermak-Rd...its a tough call, its nice and clean and doesnt need repairs.... but its next to a vacant lot, heating is 2 gas space heaters in each unit(6 bedrooms, and no heat in any of em!)

At that time we updated the electrical, heating, and in Dec 2016 put on new roof.

Oil is a pain in the butt and the tenants will complain of high heating bills.