12 yr old philco ac unit is out of refrigerant. Customer had unit refilled last year. Left quote to refill and replace evaporator coil. While looking at the furnace I saw that the vent is disconnected from customer hot water tank power vent. They had issues with water tank not working and disconnected the vent. Explained to them that the vent should not be disconnected and they run the chance of carbon monoxide in the home. Told them we have a plumbing department that can work on it for them. They will call in if they want plumbers out. Customer wants a quote to replace the hvac system before making a decision on repair. Estimate is scheduled today at 4pm.