The date of manufacture of a Rheem furnace is encoded in the product serial number and is simple to decode using charts available on the Rheem website or other online resources. Some models have a separate date stamp in addition to the coded serial number.
Rheem furnaces have five different types of serial number, and embedded in each number is valuable information such as model, location of manufacture and date of manufacture. On all models, the date is listed immediately after the single letter location code, usually in the middle of the serial number sequence. For example, in the following code "M" is the location code, and the product was built in the 28th week of 2007: OR177 M2807 00097.
Serial number placards are installed in plain view on the front of the device and should not be removed. Knowing the model and year of manufacture is important when ordering parts or requesting service on your furnace or determining the age of a furnace in a home sale situation.
In the case of a missing serial number placard, qualified service technicians can often determine the age and model of a furnace by sight or by identifying installed parts such as pilot lights or thermostats.