Trane SWT3971 Pressure Switch 340155-7026 the 097720 (EX5-U21) is the
Yard notes & kiln story
Description
Trane SWT3971 Pressure Switch 340155 7026 the 097720 (EX5 U21) is the the 097720 (EX5 U21) is the direct technical successor and is interchangeable with earlier EX U series models of the same capacity rating it is professional practice to test the lamp and inspect the socket for signs of arcing before concluding the ballast is the sole point of failure