How old is my York heat pump?

Serial number age decoder for York heat pumps: 2 format eras, the decode rule in plain English, transcribed tables, and the official lookup.

• York heat pump serial numbers in the 2004 to present format encode the year as digit 2 + digit 4 concatenated (0+5 = 2005) and the month as letter 3 (table below) (source: building-center.org).
• Example: serial W0K5896070 decodes to September 2005.
• York heat pump serial numbers in the 1971 to 2004 format encode the year as letter 3 via 21-letter table (table below) and the month as letter 2 (A-N, I/J skipped like style 1) (source: building-center.org).
• Example: serial WAKM011379 decodes to 1980 or 2001 (January).
• The 1971 to 2004 format is ambiguous: Letters A-N repeat (1971-1984 vs 1992-2004): 21-year cycle. Some serials carry a parenthesized leading letter e.g. (S)EBHM062202 - ignore it. Style ran to Oct 2004, so 2004 has BOTH styles.
• York's official lookup at york.bosch-hcgroup.com returns warranty details ('HVAC WARRANTY LOOKUP').

Format eras

• 2004 to present VERIFIED
  A#A#######digit 2 + digit 4 concatenated (0+5 = 2005)
• 1971 to 2004 VERIFIED
  AAAA######letter 3 via 21-letter table: A=1971/1992 B=1972/1993 C=1973/1994 D=1974/1995 E=1975/1996

How to read the serial

2004 to present formatVERIFIED

Shape A#A####### · example W0K5896070 · confidence high

Year

digit 2 + digit 4 concatenated (0+5 = 2005)

Week or month

month = letter 3: A=Jan B=Feb C=Mar D=Apr E=May F=Jun G=Jul H=Aug K=Sep L=Oct M=Nov N=Dec

Plant

letter 1: A=Apodaca N=Norman S=Source One W=Wichita

Example: serial W0K5896070 decodes to September 2005.

1971 to 2004 formatVERIFIED

Shape AAAA###### · example WAKM011379 · confidence high

Year

letter 3 via 21-letter table: A=1971/1992 B=1972/1993 C=1973/1994 D=1974/1995 E=1975/1996 F=1976/1997 G=1977/1998 H=1978/1999 J=1979/2000 K=1980/2001 L=1981/2002 M=1982/2003 N=1983/2004 P=1984 R=1985 S=1986 T=1987 V=1988 W=1989 X=1990 Y=1991

Week or month

month = letter 2 (A-N, I/J skipped like style 1)

Plant

letter 1: A=Addison B=Blackville C=Canada D=Medina E=Elyria M=Madville N=Norman W=Wichita X=Mexico Y=York

Example: serial WAKM011379 decodes to 1980 or 2001 (January).

Where the data plate is on a heat pump

On the outdoor unit, same place as a condenser: a plate on the side or back of the cabinet near the line set. The indoor air handler carries its own plate with its own serial.

General guidance, not brand-specific: the owner's manual or the installer can point to the exact spot. See the data plate guide.

For scale only: the InterNACHI Standard Estimated Life Expectancy Chart for Homes lists Heat Pump at 10 to 15 years of expected service (nachi.org). That chart is a guideline, not a prediction for your unit.

Sources

• https://www.building-center.org/york/
• img: YORK-Serial-Number-Style-1.jpg (transcribed)
• img: YORK-Serial-Number-Style-2.jpg (transcribed)
• https://york.bosch-hcgroup.com/residential-equipment/warranty-and-registrationofficial

Frequently asked questions

How do I tell the age of a York heat pump from the serial number?

In the 2004 to present format the year is digit 2 + digit 4 concatenated (0+5 = 2005) and the month as letter 3 (table below). Example: serial W0K5896070 decodes to September 2005.

Where is the serial number on a York heat pump?

On the data plate. On the outdoor unit, same place as a condenser: a plate on the side or back of the cabinet near the line set. The indoor air handler carries its own plate with its own serial.

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