For each type and size of water heater. Signed by manufacturers of water heaters certifying that products furnished comply with requirements. Written warranty, executed by manufacturer agreeing to repair or replace components of water heaters that fail in materials or workmanship within a specified 5-year warranty period. Rheem Water Heater Div. Comply with UL 174.
Number depends on application.
Factory installed, magnesium. Not required if cold-water inlet is near bottom of storage tank. Comply with UL 499. Without hot-water storage. Comply with UL 174, and listed by manufacturer for commercial applications.