Residential Portable AC Units

[william now]

Have a customer with portable residential AC and getting cigarette smoke from a neighbor that is seeping into the house through the AC venting hose. Are there units that could prevent this?

[FaultCode]

Smoke is only coming in when unit is switched off we assume as the hose is positive pressure when unit is running.

Are there any other open vents or windows in the room where outside air is getting drawn in when unit runs?