Assembly or fitting with insulating material isolating joined dissimilar metals, to prevent galvanic action and to stop corrosion. Comply with NEMA ICS 2 and UL 508. NEMA ICS 6, Type 12. 120-V ac, using integral control power transformer. Overload relay in each phase.
Switches lead pump to lag main pump and to two-pump operation.
Switches lead pump to one lag main pump and to three-pump operation. Unit suction and discharge pressure gages. Sounds alarm when backup pumps are operating. Unit suction and discharge pressure gages. Protect flanges, pipe openings, and nozzles.