In the later letter format, the first letter gives the year and the second letter gives the month. For example, in the serial number MM.BA-165804, the first M means 2020, the second M means December, BA records other production information, and 165804 identifies the unit. Therefore, the manufacture date is December 2020.
Rinnai used the numeric format from 2000 through May 2010. The letter format starts in June 2010; the two date ranges do not overlap. A serial beginning with two digits uses the numeric format. A serial beginning with two letters uses the letter format.
This rule is for North American Rinnai tankless water heaters. The model number helps identify the product as a tankless unit. Appliage recognizes Rinnai’s boiler model series (i, IP, M, E, Q, QP and RCB) and returns no tankless date for them; wall furnaces and EnergySaver direct vent heaters share the tankless date table.
Find the Age of Your Rinnai Water Heater with Appliage
Look on the Left Side of the Tankless Cabinet
Rinnai identifies the left side panel as the normal serial label location. For an outdoor unit installed in a recess box, another information sticker may be inside the recess cover. Take a photo that includes the product description, model number, and serial number so a tankless label is not confused with a boiler or wall furnace label.
Enter the Full Rinnai Serial Number
Type the complete Rinnai serial number into Appliage. You may include or omit the printed periods and hyphens. If the serial starts with two digits, Appliage takes the first pair as the year and the second pair as the month. If it starts with two letters, Appliage matches the first letter to Rinnai’s year table and the second letter to its month table.
The serial number supplies the manufacture month. Enter the model number too so Appliage can confirm that the unit is a North American tankless water heater rather than a boiler or wall furnace.
Rinnai Water Heater Age Rules
| Serial example | Date fields | Period |
|---|---|---|
| 08.05-004974 | 08 = year; 05 = month | 2000 through May 2010 |
| MM.BA-165804 | First M = year; second M = month | June 2010 onward |
Periods and hyphens only separate the fields. Both 0805004974 and 08.05-004974 produce May 2008.
Numeric Rinnai Serials: 2000 through May 2010
For a numeric serial, add 2000 to the first two digits to get the year. The next two digits are the calendar month. The remaining digits identify the water heater.
| Month code | Month | Month code | Month |
|---|---|---|---|
| 01 | January | 07 | July |
| 02 | February | 08 | August |
| 03 | March | 09 | September |
| 04 | April | 10 | October |
| 05 | May | 11 | November |
| 06 | June | 12 | December |
Letter Rinnai Serials: June 2010 Onward
For a letter serial, match the first character to the Rinnai year table and the second to the month table. The letters after the date code record other manufacturing information, followed by the unit number.
| Year code | Year | Year code | Year |
|---|---|---|---|
| B | 2010, June onward | L | 2019 |
| C | 2011 | M | 2020 |
| D | 2012 | N | 2021 |
| E | 2013 | P | 2022 |
| F | 2014 | R | 2023 |
| G | 2015 | S | 2024 |
| H | 2016 | T | 2025 |
| J | 2017 | W | 2026 |
| K | 2018 |
| Month code | Month | Month code | Month |
|---|---|---|---|
| A | January | G | July |
| B | February | H | August |
| C | March | J | September |
| D | April | K | October |
| E | May | L | November |
| F | June | M | December |
Where the Two 2010 Formats Change
The numeric rule stops at May 2010. A numeric serial that calculates to June 2010 or later gets no date from this rule. Rinnai’s letter code B starts in June 2010, so a 2010 letter format date must fall between June and December.
Why the Numeric Rule Starts in 2000
Rinnai has described its North American tankless launch as 1999 in one company account and 2000 in another. A 2008 CPSC notice lists Rinnai serials beginning with 0002 for units made in February 2000. No official Rinnai record assigns a date to a 1999 tankless serial, so Appliage begins the numeric rule in 2000. A serial that begins with 99 gets no date.
A serial also gets no age when its numeric month is outside 01 through 12, its letter is absent from the Rinnai tables, or its product is a boiler or wall furnace that uses another rule.
Sources
- Rinnai Direct Vent Service Manual. The manual defines the year and month positions and publishes the later letter tables.
- CPSC recall 08-199. The federal notice independently confirms the first four numeric date positions and lists units made in February 2000, the earliest date in the records.
- Rinnai Technical Bulletin 174. This tankless water heater bulletin includes a modern letter format serial.
- Rinnai Technical Bulletin 179. This bulletin shows a complete serial and identifies the left side panel as the serial number location.
Appliage is an independent appliance age research tool. It is not affiliated with or endorsed by Rinnai. See how the evidence standard works on our About page.
