Water Heater Age

Can anyone comfirm the age of this Rheem water heater. Model#666HS-400 and Serial # [FONT=Times New Roman]RD 470 19667. I was thinking possibly 1966 but man that seems old and it is located in a crawl too. [/FONT]

Water Heater
Manufactured by Rheem
Sample Serial #:
RN 0197147899
Using the serial number locate the third through sixth digits. i.e. RN 0197147899.
The third and fourth digits are the month of manufacture.
The fifth and sixth digits are the year of manufacture.
Using this sample serial number. The unit was manufactured in January, 1997.

Going by that I would say 1996 is the year for that one.


Serial # RD 470 19667

Going by your date code method it is a 2001 model not a 1996

April 1970 by my records.

That’s a great example of why spaces, hyphens, and pre-printed digits are very important to serial numbers.

That’s a unit from the time when leading zeros were not used for the most part. As Ian noted, the third through sixth digits would normally be used, but since you’ve included the spaces, if that was manufactured today, it would be RD 0470 19667.

You’re right Chuck, I flip flopped the year and month.

RR, care to share how you come up with 1970?

When all esle fails look at the ANSI date that will help to put an approximate age to the unit.


how do i find this part 666hs/300 ser;RD77016915

Trying to find part #666hs-300 ser:RD4701967

Are you guys friggin serious. It was manufactured in the 47th week of 2001