Rheem serial age
Manufacture date from the rating-plate serial. Same family as Ruud, WeatherKing. A printed MFR date on the plate still wins.
Rheem
Type the serial off the rating plate. Spaces and hyphens are ignored. Manufacture date is not the install date.
Diagnose this call
Age is open. The walkthrough is the seat.
Where the plate is
Furnace: inside the door. Outdoor: side of the wrapper. Water-heater serials use a different month/year style — pick HVAC vs water heater before you trust the decode.
Styles
Current HVAC
W291013412
Leading plant letter, then week, then year. W2910… = week 29 of 2010.
Older
CB5D302F099903346
Find the factory letter F, M, G, W, or N in the middle. The four digits after it are week then year.
Same date-code family: Ruud.
Cross-checked against Rheem HVAC age. FieldBench does not host or republish that page. Letter charts we could not verify are linked out instead of invented.