Tenant stated there was water coming out of the unit shortly after Shelby, Jesse, and I left the property. Added vent stack on T of drain line, as well as two cutoff valves. With the 2 cutoff valve isolating both sides of the primary drain we were better able to purge with nitrogen to clear out the line. Tested many times by pouring water into the drain pan. We could see water coming out of the drain line outside. Unit is draining properly at this time. Turned on and shut off unit several times to verify. Unit in good working order upon departure.
