Sounds like it would have happened had you tested the system at time of inspection.I remember him turning on the  thermostat, but we definitely did not run the furnace long enough (5-10 minutes) to start hearing the sound.

I'm not a programmer though, so I'd still have some missing pieces... 

I'm a web applications programmer by trade and invest in real estate as a way to transition to a less stressful life. 

I live in northern nm and I am currently employed through Los Alamos National Labratory as project scheduler/programmer. 

We still need to test with the water on, but I feel pretty confident there are no major issues.After having the power turned on, we revealed the issue with the hvac was a faulty thermostat. 

On further questioning I was refer to the top guy of two of these companies who said ALL COOLING UNITS are designed by manufacturer to keep the interior 20 degrees lower that the temperature outside and the thermostat should be set to reflect that.

Upgrade/repair/replace existing boiler items that need it, go w/ window AC units and see if you can legally have thermostats that have a maximum setpoint of 72 degrees.

That house would normally have about $3,500 - $4,000 in electric costs but I had maybe $350 for the first year and $1,200 for the second (tenants got crazy with 66 degree cooling during the summer, now the thermostats are password locked lol) and the total system cost was roughly $20,000 minus the 30% tax credit.  

Each unit will have its own thermostat and be able to control the heat resulting in fewer tenant complaints 3.

I'm sort of a data nerd/programmer and I'm starting a new REI data business starting coverage first in DFW.