Modern Reliance tanks use year and week
For an eleven-character serial starting with four digits, followed by a letter and six digits, read the first pair as the year and the second as the week. 1211A018632 gives week 11 of 2012. The A after the date is not a month code in this layout.
Energy Trust lists Reliance in its State Industries group and dates this layout from about 2008. Building Intelligence Center shows the same Reliance style. A week result gives an approximate month, not an exact day.
Why an older letter code may return no result
Older Reliance examples include L92441351 and C91A136750. Published guidance is inconsistent about calendar versus fiscal month codes. Applying the familiar A = January table to every old Reliance can therefore give a false month or year.
This page deliberately leaves those legacy styles undecoded pending better evidence. Send Reliance the full model and serial or look for a printed manufacture date; do not substitute the installation sticker as a factory date.
Reliance brand versus a rental provider
A rental or service-company sticker is not necessarily the appliance brand. Find the actual manufacturer’s rating plate. If it says another maker, choose that brand in the picker, even when your bill or service label says Reliance.
Common questions
Why does a number such as 1211 mean March?
It means the eleventh week of 2012. The decoder places that week approximately in March; 11 is not November in this format.
Does age tell me when to replace the tank?
No. Manufacture age does not measure condition, maintenance history or remaining life. A qualified service professional can assess the actual tank.
Where is the label?
Look on the tank jacket for the serial and model fields. Keep the complete code, including the letter after the first four digits.
Worked examples
| Serial | Style | How it reads | Made | Example from |
|---|---|---|---|---|
1211A018632 | Year + week (modern tank serials) | 12 = year ’12; 11 = week 11 of the year | Week 11 of 2012 (around March) | Building Intelligence Center |
Not affiliated with Reliance. Brand names describe decoder compatibility. Manufacture date is not installation date.
Sources
- Energy Trust of Oregon: Serial Number Decoder: Water Heater (PDF)Used for: Year + week (modern tank serials).
- Building Intelligence Center: reliance water heater ageUsed for: Year + week (modern tank serials).