Can you tell the age of a Rinnai water heater by the serial number? Yes. Rinnai -just like any other brand- encodes the manufacturing date in the serial number.
There are two different styles of Rinnai water heater serial numbers. The old style was used until 2009, and the new style is used today. In this article, we’ll discuss how to determine the Rinnai water heater age from the serial number.
How to decode the Rinnai water heater serial number?
Old serial number format.
The date of manufacture is coded in the first four digits of the serial number. The first two numbers represent the year, and the third and four numbers represent the month of production. This serial number format was used until 2009.
Serial number #06.03-012345
By reading this serial number, it indicates your Rinnai water heater was manufactured in March 2006.
New serial number format.
Starting in late 2009, Rinnai water heater serial number has a new format. The date of manufacture is coded in the first two digits of the serial number. The first letter represents the year and the second letter represents the month of production.
Serial number #BC-012345
According to this serial number, the unit was manufactured in Jan 2010. See the table below to identify each letter.
| LETTER | YEAR | LETTER | MONTH |
| A | 2009 | A | January |
| B | 2010 | B | February |
| C | 2011 | C | March |
| D | 2012 | D | April |
| E | 2013 | E | May |
| F | 2014 | F | June |
| G | 2015 | G | July |
| H | 2016 | H | August |
| J | 2017 | J | Septermber |
| K | 2018 | K | October |
| L | 2009 | L | November |
| M | 2020 | M | December |
| N | 2021 | ||
| P | 2022 |
Another way to determine the Rinnai water heater’s age
Most new Rinnai water heaters make it easy to figure out how old they are. The sticker tag has the year of the manufacturer written on them. You could also look at the user’s manual to determine your water heater’s age. The installation date should be printed there.
It is simple and easy to figure out the age of the Rinnai water heater from the serial number. On older models, though, you may need to do a little digging. You could start by figuring out what the serial number means. Once you know what to look for and have the key, you might find it fun to figure out how old your water heater is.
