Checking for leaks on a Large Rooftop Air Handler is crucial for the units efficiency rating. Before the unit leaves the manufacturer, it tested to insure factory settings. Once the unit is delivered and set up, it is retested to those settings verifying the units integrity. As a third party to this procedure, TAB Services can test and certify the results of leakage testing in equipment casings having as little as a few cfm of leakage up to over 1500 cfm of leakage. We are capable of testing with pressures up to +16” w.c. and negative pressure testing down to -16” w.c.