To spray them I would suggest an airless with a 310 tip or an HVLP gun running off a jobsite compressor.

I winterize a few houses for customers who winter in Florida , first I shut the water down at the street , then we drain everything , kill the electric to the water heater , tape over the breaker , blow the house out with a 125 cfm diesel compressor , then we have a 55 gallon drum of RV antifreexe and we use a air diaphram pump and fill the pipes with the pink stuff.

You can pay an HVAC guy to actually remove the AC compressor until it is leased if you are really worried about it.

Found out A/C compressor is broken and house will need a larger electrical box and connectors for aluminum wiring.

Typical stuff like recharging, replacing fan motors, replacing compressors, occasionally replacing an entire unit.Thanks for the help

Install of the AC compressor is usually extra so add another $400 to 600 or so for that installation since it is specialized. 

You biggest, common items that would need to be repaired are the air handler unit & the compressor. 

This includes all motors, compressors, boilers, furnace, chillers, pipes, ducts, radiators.Plumbing systems.

Compressor?

I would use sand or 3/4 inch stone before using dirt, you wouldn't want the dirt to compress or compact over time and leave a void under the wall