Thermal sensors are being furnished on all projects to meet the International gas code. This code is in effect in most areas right now. The sensor is in a liquid tight quick seal, the same used for fire system nozzles. There is a small possibly that the water got into the wiring from inside the duct, unless there are water leaks in the welded duct. The water may have gotten between the fire wrap and the duct and ran down into the “j” box where the electrical connection is made. The sensor can be bypassed in the electrical panel, but may be a code issue later. - Captive Air
From Don: bypassing should not be a permanent option. Please watch out for leaking ductwork or seals that are leaking on the sensors that could compromise them as it will shut down the system is it shorts out. Contractors- please leak test all ductwork thoroughly. There is a section on proper water leak testing on the Enviromatic.com web site.