Weil McLain® HVAC age

How to determine the date of production/manufacture or age of Weil McLain® brand HVAC Systems.

The industry average service design life for most forced air furnaces is 15-20 years, and the industry average service design life for most air conditioning condensing units is 10-15 years. The average service design life of boilers can vary from as little as 10 years to as many as 50 years depending on the type and quality of materials used in their manufacture. Routine upkeep/maintenance, regional weather/climate, and location/placement of the mechanical systems will all play critical roles in the longevity of these systems.

Parent Company: Marely-Wylain Company, a subsidiary of SPX Corporation

Subsidiaries or other related brands: Weil McLain | Williamson Thermoflo

The date of production/manufacture or age of Weil McLain brand HVAC equipment can be determined from the "CP" number located on the unit as a separate tag or sticker.

Example CP number styles/formats found:

Style 1: CP 2530051

Style 1: CP 2530051

The Date of Manufacture is determined from the unit's CP Number which runs consecutively. The CP numbers are commonly found on a separate tag or sticker apart from the typical data tag.

We have included an abbreviated chart listing CP numbers from 1988 through 2009 (see below) for your convenience. In addition Weil-McLain also has a CP number Look-up Tool available on their website and linked below.

Note:

All modern Weil McLain systems currently use 7-digit CP numbers.

6-digit CP numbers are generally from the early 1980's and prior. You will typically need to contact Weil-McLain directly for manufacture date assistance on any 6-digit CP numbers encountered, or use other methods such as date stamps on the gas valve etc. Our History information below may also be of assistance to narrow the approximate range of manufacture. ALL information on the data plate and system will be critical to help determine the age.

CP Lookup Tool from Weil McLain

Click Here ForCP Lookup Tool

Note:

All modern Weil McLain systems currently use 7-digit CP numbers.

6-digit CP numbers are generally from the early 1980's and prior. Their CP Lookup tool may assist you with the older numbers, but you will need to follow their instructions by adding a zero preceding the first digit of the CP number. (i.e. make CP123456 to read CP0123456)

Our History information such as factory location changes and company mergers below may also be of assistance to narrow the approximate range or era of manufacture. ALL information (factory address and/or parent company information) on the data plate and system will be critical to help determine the age.

If you still require further assistance in determining age or manufacture date, contact Weil-McLain at (219) 879-6561 or (866) 783-9276 and ask for Technical Services.

Weil McLain History¹

1881 - Founded by Isadora and Benjamin Weil as a small plumbing and heating house in Chicago, Illinois, under the name “Weil Brothers”
1918 - Bought out their largest boiler supplier, J. H. McLain Company of Canton, Ohio
1919 - The company name “Weil-McLain” was established
1921 - Weil-McLain moved the boiler operations from Canton, Ohio to the present facilities in Michigan City, Indiana
1927 - added a foundry operation in Erie, Pennsylvania
1953 - the company sold its wholesale operation to focus on manufacturing
1964 - Weil-McLain started acquiring companies
1966 - the boiler operations became known as the “Hydronics Division” of Weil-McLain
1976 - the corporate name was changed to Wylain, Inc. of which Weil-McLain became a division (data plates state "Weil-McLain, a division of Wylain, Inc.")
1980 - in late December, 1979, Wylain, Inc. announces agreement to a takeover (merger) by The Marley Company of Mission Woods, Kansas (manufacturer of cooling towers and heat exchangers) in a transaction valued at $93.8 million. Wylain would be merged into a wholly owned subsidiary of Marley. The company name was changed to Weil-McLain a division of The Marley Company
1981 - Marley Company mergers and corporate name changed to Marley-Wylain Company
1993 - United Dominion Industries of Charlotte, North Carolina, purchased The Marley-Wylain Company
1999 - Weil-McLain expanded its boiler line and entered the oil furnace market by acquiring Williamson Thermoflo
2001 - United Dominion Industries was acquired by SPX Corporation of Charlotte, North Carolina. Weil-McLain is now "Weil-McLain, a division of The Marley-Wylain Company, a subsidiary of SPX Corporation"
2005 - after outgrowing the original Michigan City manufacturing facility, Weil-McLain opened a manufacturing plant and distribution facility in Eden, North Carolina. The Michigan City, Indiana location continues its cast iron foundry operations and houses a state of the art laboratory and testing facilities alongside an engineering and development center.
2012 - Weil-McLain opened an administrative office in Burr Ridge, Illinois (a suburb of Chicago).

¹Excerpts from various industry sources

Every effort is undertaken to offer you correct and concise information to assist you in determining the age or manufacture date of HVAC/R equipment. Users relying on this information do so at their own risk.

Page last updated: 12/16/2023

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