Paloma Water Heater Age Lookup
Paloma pioneered tankless heating and built many of the early Rheem tankless units. Enter your serial number to find the manufacture date and age of your Paloma-built heater. Free and instant.

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Finding Your Paloma Serial Number
Check these four spots on your Paloma water heater
Common Locations
What to Look For
- White or metallic manufacturer sticker
- Labeled "Serial No." or "S/N"
- Typically 8–12 characters long
- Usually near the model number
Can't find it? Try removing access panels or checking behind the temperature dial.
Paloma Serial Number Examples
Don't worry if yours looks different - Paloma has multiple formats and our system can decode most variations.
About Paloma Water Heaters
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.
Where to find the serial
Paloma tankless water heaters have the rating plate on the bottom or side of the wall-mounted unit. Paloma is the majority owner of Rheem, so service and parts in North America route through the Rheem network. The serial encodes the manufacturing month and year.
What the serial actually looks like
Why the age is worth knowing
Paloma tankless units carry warranties similar to Rheem (12-year heat exchanger on most condensing models, 5 years on parts). Annual descaling is critical for warranty maintenance - skip it and Paloma will deny claims based on scale damage in the heat exchanger.
Quick answers for this brand
Is Paloma the same as Rheem?
Paloma Co. Ltd. of Japan is the majority owner of Rheem Manufacturing in North America. Paloma-branded units sold in the US are sometimes Japanese-built and sometimes Rheem-built depending on the model. Service and warranty all route through the Rheem North American network.
Where are Paloma units sold in North America?
Paloma branded tankless units have limited distribution in North America, primarily through specialty plumbing wholesalers. Most North American consumers encounter Paloma technology rebadged as Rheem or Ruud tankless. New installations under the Paloma brand are uncommon today.
Can I use Rheem parts on my Paloma?
In many cases yes - especially for tankless units built on the shared Paloma/Rheem platform. Always verify the exact part number with Rheem tech support before ordering, as small revisions matter for heat exchangers, gas valves, and control boards.

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