Or maybe even installs,
Ran a service call last spring for gas smell. Found a makeup air system duct heater with a rusted out burner assy and cracked heat exchanger. ..............So nobody ever installed the discharge air sensor for the modulating gas valve, still taped to the manifold, looks like some overheating going on.
Facility has two systems the same heres the other one.
Notice the bulb taped to the pipe.
Cleaned up the wiring a little bit too.