For a boiler made in 2000 or later, the last six digits follow YYYYMM order: four digits for the year, followed by two digits for the month. For example, the serial number 335218-200012 ends in 200012. The code 2000 gives the year, and 12 means December. Therefore, the manufacture date is December 2000. When a serial number matches either format, its ending code identifies the manufacture month and year. The model number is optional.
For Peerless boilers made before 1984, we have not found a reliable serial number rule that identifies the manufacture date. Appliage therefore cannot find the age of one of these older boilers from the serial number.
Find the Age of Your Peerless Boiler with Appliage
Step 1: Find the Peerless Boiler Rating Plate
Look for the Peerless rating plate on the outside of the boiler jacket or near the controls. Find the line marked Serial or Serial No., then copy the complete number. If the serial number includes a date code, it appears at the end, whether or not the plate separates it with a hyphen. You can leave the model number field blank.
Step 2: Enter the Peerless Serial Number into Appliage
Enter the complete Peerless serial number into Appliage. Our decoder uses the final four or six digits. For a valid serial number from 1984 or later, the result shows the manufacture month, year, and estimated age. If the serial number does not match either format, Appliage cannot calculate an age from it.
Peerless Boiler Age Rules
| Peerless boiler period | Serial number rule | What the digits mean | Result |
|---|---|---|---|
| Before 1984 | No reliable rule found | No reliable month and year key is available | No age |
| 1984–1999 | MMYY | Month 01–12, then year 84–99 | Manufacture month, year, and estimated age |
| 2000 onward | YYYYMM | Four digit year, then month 01–12 | Manufacture month, year, and estimated age |
1984 through 1999: Four Digits in MMYY Order
- Before the date codeBoiler identification
These characters identify the boiler but do not influence its manufacture date - First two digits of the date codeMonth
01 through 12 - Final two digits of the date codeYear
84 through 99 mean 1984 through 1999
The four digit code must contain a valid month and a year from 84 through 99. If the final two digits fall outside that range, Appliage cannot use the four digit code to find the age.
2000 and Later: Six Digits in YYYYMM Order
- Before the date codeBoiler identification
These characters identify the boiler but do not influence its manufacture date - First four digits of the date codeYear
The full year, such as 2000 or 2026 - Final two digits of the date codeMonth
01 through 12
The six digit code must contain a year from 2000 onward and a valid month. If the year and month point to a date in the future, Appliage returns no age.
Why These Two Date Rules Apply to Peerless Boilers
PB Heat publishes both date formats in its Peerless boiler FAQs. We also checked complete Peerless serial numbers in the Delaware Boiler and Pressure Vessel registry. The state registry lists 61-22179-0584 with a build year of 1984 and 335218-200012 with a build year of 2000. Those years match the ending codes 0584 and 200012. The state records confirm the year, while the month comes from the Peerless serial number.
Why 123456-0310 Does Not Return an Age
PB Heat’s contractor FAQ shows 123456-0310 and labels it March 2010. However, a Peerless boiler made in 2010 should end with the six digit YYYYMM code 201003. The ending 0310 has only four digits, and Peerless used that four digit MMYY format only from 1984 through 1999. Its year must therefore be 84 through 99, not 10. Appliage returns no age for 123456-0310 because it does not fit either Peerless date format.
Who Made Older Peerless Boilers?
PB Heat began manufacturing Peerless boilers in 2003. Older Peerless boilers were made by Peerless Heater Company, and boilers from 1984 through 1999 use the MMYY format explained above. A Peerless boiler owner shared a written reply from PB Heat about serial number WB 45861-1192. PB Heat identified it as a Peerless Heater Company boiler made in 1992. Its ending code 1192 means November 1992.
Why Appliage Cannot Find the Age of a Pre-1984 Peerless Boiler
PB Heat’s published dating instructions begin with boilers made in 1984. We have not found a reliable serial number rule for earlier Peerless boilers. For example, 61-19188 does not match either of the later ending date formats. Appliage returns no age because there is no reliable way to get a manufacture month and year from this serial number.
For a pre-1984 boiler, an installation invoice, building permit, warranty document, or dated service label may show when the boiler was installed. The installation date can help estimate its age, although the boiler may have been manufactured earlier.
Sources
- PB Heat Peerless Boiler FAQ, archived 2010. The manufacturer page publishes the 1984 to 1999 MMYY ending code and the 2000 onward YYYYMM ending code. It does not provide a dating rule for boilers made before 1984.
- Current Peerless Boilers FAQ. PB Heat publishes the six digit YYYYMM rule and explains when it began manufacturing Peerless boilers.
- Delaware Boiler and Pressure Vessel registry. State records independently pair complete Peerless serial numbers with recorded build years for both date code formats.
- Peerless Boilers Contractor FAQ. This page prints the conflicting 123456-0310 example discussed above.
- PB Heat reply shared on HeatingHelp. A boiler owner posted PB Heat’s reply identifying WB 45861-1192 as a 1992 Peerless Heater Company boiler.
Appliage is an independent appliance age research tool. It is not affiliated with or endorsed by Peerless Boilers or PB Heat. See how the evidence standard works on our About page.
