i have 3 hot water heaters and 2 gas boilers in a back room in the basement. directly above that are dryers for a laundromat. i have backdraft problem on one of the water heater, it gets worse if all the dryers are running. if i stand on the chimney on the roof i can feel the hot air from the dryer vent. would that be the cause of the backdraft?
are the vent pipes on the water heaters properly install?