Who makes Lochinvar water heaters
Lochinvar, LLC is based in Lebanon, Tennessee. A.O. Smith completed its acquisition of Lochinvar on August 26, 2011, describing it as “a leading manufacturer of high-efficiency boilers used in commercial and residential hydronic heating and hot water applications.” A.O. Smith’s Form 10-K for 2018 says “Approximately 40 percent of Lochinvar branded sales consist of residential and commercial water heaters.”
Basis: official (A.O. Smith release and Form 10-K; Lochinvar warranties).
This page covers Lochinvar’s residential tank water heaters. Lochinvar boilers and commercial heaters use other serial formats (see below).
Where the rating plate is
| Heater | Where Lochinvar says to look |
|---|---|
| Residential tank, 2011 on | “Approximately half to two-thirds down the length of the jacket on the front/right of the heater” |
| Residential tank, 1979 to 2011 | “Below the Lochinvar logo, approximately in the middle of the tank” |
Basis: official (Lochinvar, Warranty Information by Serial Number). Check the plate for a printed date first: Lochinvar’s residential warranties run “from the date of manufacture indicated on rating plate affixed to this water heater.”
Tanks made from 2011: year and week
Lochinvar: “The products listed above employ an eleven character alpha-numeric serial number system. Example: 1142N012345…Built the 42nd week of 2011. The first two characters signify the year built. The second two characters signify the week built. The fifth character signifies the manufacturing plant.”
| Characters | Means | In 1142N012345 |
|---|---|---|
| 1–2 | Year | 11 = 2011 |
| 3–4 | Week (01–53) | 42 |
| 5 | Plant letter | N |
| 6–11 | Production code | 012345 |
Basis: official (Lochinvar, Warranty Information by Serial Number, Rev 18). Week 42 of 2011 falls in mid-October; the checker shows the month the week falls in.
Tanks made 1979 to 2011: two letters
Lochinvar: “The above series has a two letter, six or seven number system, which is used to distinguish the warranty date. Example: KJ-1000130…Built in September of 1993. The first letter signifies the year produced. The second letter signifies the month produced.”
Year letters
| Letter | Lochinvar’s table | 20 years earlier (our inference) |
|---|---|---|
| A | 2004 | 1984 |
| B | 2005 | 1985 |
| C | 2006 | 1986 |
| D | 2007 | 1987 |
| E | 2008 | 1988 |
| F | 2009 | 1989 |
| G | 2010 | 1990 |
| H | 2011 | 1991 |
| J | 2012 | 1992 |
| K | 1993 | – |
| L | 1994 | – |
| M | 1995 | – |
| N | 1996 | – |
| P | 1997 | – |
| S | 1998 | – |
| T | 1999 | 1979 |
| W | 2000 | 1980 |
| X | 2001 | 1981 |
| Y | 2002 | 1982 |
| Z | 2003 | 1983 |
Basis: official for the middle column (Lochinvar’s table lists 1993 to 2012). The right-hand column is our inference: Lochinvar’s guide dates this two-letter series 1979 to 2011, and repeating its 20-year cycle gives these years. They follow the same 20-year letter cycle as Bradford White’s chart. The letters I, O, Q, R, U and V aren’t used.
Month letters
| Letter | Month | Letter | 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 |
Basis: official (Lochinvar). Lochinvar also notes that residential products “starting with serial number prefix SA have a six (6) year limited warranty” and earlier ones five years (SA = January 1998, our reading of the table).
If the letter could mean two years
Most year letters fit two years 20 years apart. To settle it:
- Read the rating plate. Lochinvar’s warranties refer to a date of manufacture on the plate.
- Ask Lochinvar. The Technical Assistance Hotline is 1-800-722-2101.
- Check the paperwork. An installation receipt or permit record gives a latest possible date.
The checker above lists both years and lets you pick, where both are within the last 45 years. For letters whose earlier year is more than 45 years ago, it shows only the later year, so check the plate if yours could be that old.
A forum reading to ignore. In a 2007 InterNACHI forum thread, serial BH6479275 was read as August 1994. Lochinvar’s own table gives B = 2005 (or 1985 on the 20-year cycle), not 1994.
Worked examples
| Serial | Reads | Built | Where the example comes from |
|---|---|---|---|
| KJ-1000130 | K = 1993, J = September | September 1993 | Lochinvar serial guide (stated) |
| 1142N012345 | 2011, week 42 | mid-October 2011 | Lochinvar serial guide (stated) |
| BH6479275 | B = 2005 or 1985, H = August | August 2005 (or 1985) | InterNACHI forum serial; our reading of Lochinvar’s table |
Boilers and all-number serials: ask Lochinvar
- Boilers and commercial heaters. Lochinvar’s guide lists several other formats (for example A07H00123456, a month letter then a 2-digit year: January 2007 in the guide’s own example). Its month tables for these formats contradict each other, so we don’t decode them.
- 13-digit numbers. Inspectapedia says “current (2020) Lochinvar water heater serial numbers are 13 numeric digits for which we have not yet a decoder” (its example: 1720106196457 on a model EJW020PS). They could start with the year and week or with the week and year, so the checker doesn’t guess.
- 9-digit numbers. The boiler serials in CPSC’s 2020 Lochinvar recall (103475818 to 115078306, sold after August 2016) are 9-digit numbers that don’t start with the year, so we treat 9-digit serials as undecodable.
For any of these, look for a date on the rating plate or call Lochinvar at 1-800-722-2101.
Recalls to know about
We found no CPSC recall of a Lochinvar tank water heater itself (checked 30 September 2026). These recalls involve Lochinvar products:
| Recall | What | How to tell |
|---|---|---|
| CPSC 05-274 (Sep 2005) | Robertshaw R110 gas control valves on natural gas and LP water heaters of several brands, including Lochinvar: “gas could leak from the valve, which poses a risk of gas explosion and fire.” About 178,000 units, all brands | Valves made July 25 to August 14, 2005, with production date codes 5-31 through 5-33, “although not all valves with these date codes are affected.” Electric heaters aren’t included |
| CPSC 20-141 (Jun 2020) | Lochinvar, A.O. Smith and State Proline condensing residential boilers, combi boilers and packaged systems sold after August 2016: the flue grommet can deteriorate and dislodge, letting the boiler emit carbon monoxide. About 34,300 units | Serials 103475818 to 115078306 |
| CPSC 24-018 (Nov 2023) | Lochinvar, A.O. Smith and State Industries brand condensing residential boilers, combi boilers and packaged systems, sold August 2021 through August 2023: the flue collector can crack after a high-impact event in the burner chamber, letting the boiler emit carbon monoxide. About 17,370 units | Serials 125325485 to 134830284. Lochinvar models start NCF, NKB or NKC; A.O. Smith models start ACB; State Industries models start SCB. The brand name is on the front of the unit |
Basis: official (CPSC notices in the sources). For the boiler recalls, Lochinvar’s recall line is 833-232-9706 and serials for the 2020 recall can be checked at waterheaterrecall.com; for the 2024 recall, serials can also be checked at waterheaterrecall.com (flue collector look-up) or via Recall Notices on lochinvar.com, and A.O. Smith and State boiler owners are told to contact their installer. Our recall check covers water heater notices, so check boiler models on the CPSC notices directly.
What the age means
We found no lifespan figure from Lochinvar. Its residential electric warranty (2023) covers the tank for 6, 8 or 10 years depending on the model; a warranty isn’t a lifespan. A.O. Smith, Lochinvar’s parent, says tank water heaters last 8 to 12 years, and across published sources a tank typically lasts about 11 years (our summary; most figures fall between 8 and 15). See how long water heaters last.
When a Lochinvar tank needs replacing, check the plumber’s quote against installed water heater prices, with labor and state figures.
Limitations
- The checker decodes Lochinvar’s two residential tank formats only.
- Years before 1993 come from repeating Lochinvar’s 20-year letter cycle (our inference); Lochinvar’s printed table starts at 1993.
- Lochinvar hasn’t said exactly when in 2011 the tanks switched from letters to year and week.
- The serial gives the build month, not the install date.
Checked against the sources below on 30 September 2026.
