The dance studio located in the shopping center has an individual 40 gallon water heater. The water heater was shut down by an excel technician due to the vent pipe being disconnected. The excel tech noted the vent pipe was disconnected and laying loose on the roof of the building. Southside Plumbing inspected the attic space and discovered the vent is disconnected in the attic as well. The vent will have to be reconnected in both places before the heater can be returned to service safely.