Paloma Water Heater Age Tool

Paloma water heaters are manufactured by Paloma Co., Ltd., a Japanese company founded in 1911 in Nagoya, Japan, where it began by producing alcohol lamps and later expanded into gas appliances. Paloma became a pioneer in instantaneous gas water heating technology, developing some of the earliest automatic tankless water heaters and establishing a global reputation for precision engineering and gas combustion expertise. The company operates manufacturing and distribution subsidiaries across Asia, Australia, and North America, and its products are sold in dozens of countries under the Paloma and Rheem brand names — Paloma is the majority shareholder of Rheem Manufacturing, the largest water heater manufacturer in the United States. In North America, Paloma-branded products are sold primarily as high-efficiency tankless water heaters targeting both residential and light commercial applications.

Paloma tankless water heaters are known for compact wall-mounted designs, precise electronic modulation, and consistent hot water delivery. North American models are engineered to meet or exceed ENERGY STAR efficiency thresholds, with Energy Factors well above those achievable by tank-style storage heaters. The units feature electronic ignition, sealed combustion options for direct vent installation, and digital temperature controls. Paloma produces both indoor and outdoor-rated tankless models in input capacities ranging from roughly 120,000 to 180,000 BTU/hr, capable of supplying multiple simultaneous fixtures in average-sized homes. The brand is distributed through a network of plumbing wholesale distributors and select specialty retailers, and units are typically installed by licensed plumbing or gas contractors.

Service support for Paloma tankless units in North America is handled through the Rheem/Paloma service network, with parts available through authorized distributor channels. The serial number on a Paloma unit encodes the month and year of manufacture and is found on the rating data plate, typically visible on the front or side panel. Two broad serial formats exist: the more common Style 1 uses a letter prefix of one to four characters (R, RH, RNG, or RHNG) followed by the two-digit year and two-digit month before the unit serial digits; Style 2 uses either a dotted YY.MM-serial format or an all-numeric serial where the first two digits represent the year and the next two represent the month. Both formats use a 50-year pivot so that codes above 50 decode to the 1900s and codes 50 and below decode to the 2000s.