Jetglas Day & Night water heater age decoders, Day & Night water heater company history, & water heater manual sources.
In this article series we give details of how to decode water heater age for all water heater brand. We also discuss the conditions, maintenance, and factors that affect how long a water heater can be expected to last.
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[Click to enlarge any image]
YMnnnnnnn where the first character encodes the year in a 20-year cycle running as follows
First character Y = Year of manufacture
F = 1989, G = 1990, H = 1991, J = 1992, K = 1993, L = 1994, M = 1995, N = 1996, O is not used
P = 1997, Q & R not used, S = 1998, T = 1999, U-V not used, W = 2000, X = 2001. Y = 2002, Z = 2003
A = 2004, B = 2005, C = 2006, D = 2007, E = 2008, F = 2009, G = 2010, H = 2011
I = 2012, J = 2013, K = 2014, L = 2015, M = 2016, N = 2017, P = 2018, S = 2019
Second character M = Month of Manufacture
A=January to M = December, with the letter "I" not used
Example: Serial No: LF3337645 (Amber PA plant) from reader Cecil Lockyer
L = either 2015 or 1994
F = June
The following is our guess based on examining various Day & Night water heater data tags and comparing those with what's known about the building age or other contextual information where the water heater was found:
NNYYWW
where YY is the 2-digit year
and WW the 2-digit week of manufacture.
If you have an older Day & Night Water heater like Jeff's, shown here, try this age decoding and compare that with the known age of the home as a test of reasonableness.
Post a photo of your water heater and its data tag along with comments at the end of this page.
Below: as you may not find an original Day & Night electric water heater manual, we offer a more-modern copy from Bradford White that may be helpful in inspecting, repairing, or maintaining your older Jetglas water heater.
Above: a Day & Night Jetglas water heater advertisement from 1961.
The Day and Night Jetglas Jupiter-model water heater a well as some other model names were were products of William J. Bailey's Day & Night heater company that began with Bailey's invention of a solar water heater in California in 1909.
The "Day & Night" name reflected Bailey's design that combined a solar heating element (obviously only collecting heat in the daytime) and an insulated hot water storage container that would continue to provide domestic hot water "at night".
Jetglas referred to a liner coating the interior of the hot water storage tank that gave long tank life: a feature that the company promoted by advertisements that warned of leaky water heaters from its competitors. We show some of those advertisements from the 1950s and 1960s below in this article.
There were earlier efforts at solar water heating, as you can read
at SOLAR WATER HEATER ANTIQUE but it was Bailey who pioneered the use of convection to circulate and heat water, insulation to retain water heat, and other water heater features.
You'll see that phrase in some of the early patent disclosures we include later in this article.
Below: three pages of an advertising brochure for an early Day & Night Water Heater, showing the heater's internal design.
Excerpts:
The Day & Night Combination water heater is so called because it combines the storage tank and heater which were separate parts in earlier methods of heating water. The storage tank in that case consisted of a range boiler, and the heater was generally a small coil type heater connected to the boiler at one side.
The Day & Night Combination boiler is made of the same high-grade hot rolled annealed steel that is used in the highest-priced automatic water heaters. It is welded by the electric arc process on an automatic seam welder which assures greater strength and uniformity than is possible by hand-welding.
Galvanized by the hot dip method in our own plant and subjected to careful inspection inside and out, the Day & Night Combination boiler receives the same careful attention given all Day & Night high quality water heaters.
The exclusive flue design of the Day & Night Combination accounts for from 15% to 20% greater economy than the conventional straight flue and baffle. This Day and Night feature is known as a "heatwave" flue and is also found on certain Day & Night automatic models.
The burner in the Day & Night Combination heater is an important factor in trouble free operation of the heater and is also an exclusive Day & Night design.
Bailey's concept of a well-insulated hot water storage tank was a key feature that he later extended to a gas-fueled water heater, and the company later expanded to produce other heating and even air conditioning equipment.
Thanks to Wikipedia's entry on the history of ICP - International Comfort Products - who own the brand:
Day & Night began as a solar water heater company in 1909 in Monrovia, California, providing Californians with round-the-clock hot water. It ventured into space heating in 1930s.
Photo above of Bailey posing by a sign for the Day & Night Solar Heater Co., from Butti & Perlin, 1980 cited below.
After extinguishing the name in 1997, the Day & Night brand name was resurrected in Western US and Canada in 2009. - 2022/01/21 original source: https://en.wikipedia.org/wiki/International_Comfort_Products
Your water heater was produced by that original company at its La Puente, California plant.
By the 1930s the Day & Night company was also producing heating and air conditioning equipment.
Other sources point out that the original Day & Night brand was bought by Dresser Industries in 1945.
Below: In the U.S. in the 1950s and to at least the mid 1960s, the Day & Night Water Heater Co. warned consumers that lesser water heaters may leak and flood their home.
Like a lot of mechanical systems brands tracing the history of the Day & Night heater brand is dizzying, with companies being bought, buying themselves back, merging, and later disappearing only to reappear in a new incarnation.
The current "Live" version of the Day & Night Brand is at https://www.dayandnightcomfort.com/ whose actual physical location was not found at that web page.
Above: W. Bailey's 1917 Solar water heater patent showing the solar panel and an insulated water storage tank in the building's attic space.
Below: Lee Bailey's portable solar power generator and water heating system, patented a century after William Bailey's original works.
Also see RANGE BOILERS still found in use in some buildings.
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Below you will find questions and answers previously posted on this page at its page bottom reader comment box.
@Anonymous,
That heater has worked well for many decades, how nice.
By 'acting up', what do you mean? Is it perhaps something worth fixing rather than replacing all together?
On 2023-09-23 by Anonymous
Here is my Jetglas- it's been acting up and I am considering replacing it although it still works. From this site, it looks like it was built in 1969! Same age as me.
@Paul Virciglio,
Thank you so much for that excellent Day and Night water heater data tag - we will be sure to keep it with this article.
It looks as if that heater was made in the 1940s, during WWII, possibly as early as 1940.
On 2023-08-10 by Paul Virciglio
Removed this water heater from a house built in the 1920's.
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For an all-numeric Day & Night Jetglas Jupiter water heater, yours is a reasonable guess.
A second guess using digits #3&4 for YY and #5&6 WW would be 1961 week 43 - a reasonable guess.
A third guess using digits #3&4 for WW and #5&6 for YY would be 1941 week 61 which makes no sense (we've only got 52 weeks in a year)
So IMO your heater could be your guess (week 12 of 1961) or mine (week 43 of 1961).
Now let's do a context and sanity check: are the country and city of the home where this Day & Night Jetglas water heater is installed, and in what year was that home built?
Two points to consider, noting Jeff's similar Day & Nite water heater data tag discussed with reader Ned, 2022-01-21.
Jeff said his Jetglas heater was in service for "50 years"
Now note his SN begins with
430866
If digits #3-4 of that Sn - the 08 part - were the year then ... hold on: we know the Jetglas is older than 2008 and younger than 1908 ( the company in fact began operating in 1909). So on this data tag digits #3-4, the "08" won't be the year of manufacture.
Using the first two digits - 43- would put this heater's construction year at 1943- making it at 79 years old (possible but unlikely)
Using the last of Jeff's Jetglas heater S/N - 66 - would put the heater's year of manufacture as 1966 - a reasonable guess and in that "50 year old" ballpark age he was giving.
So from Jeff's example, an all-numeric Jetglas Day & Night water heater with a data tag looking like yours and his, would be the format
NNWWYYwhere WW is the 2-digit week of manufacture and YY is the 2-digit year.
On 2022-06-10 by Timsplumbco - tell me the date of this Day & Night water heater?
Hello;
Can you tell me the date of this Day & Night water heater?
It's "Registration No. is: 126143 553215.
Photograph of label is attached.
I am guessing that it's the 12th week of 1961.
Thanks.
Tim
[Photo above]
One thing to add about the tank/label is the house here was built in 1970(1) or so, and as far as I know, the water heater was never replaced.
Its just been chugging along for 50+ years, apparently. I guess those old Jetglas ads were accurate - it really has lasted twice as long as other water heaters. - 2022/01/22
On 2022-01-21 by Inspectapedia Com Moderator (mod) - more history of the Day & Night Water Heater & HVAC Company
@ned,
Thank you for the helpful question and Day & Night water heater data tag - we'll be sure to add that to the article above as it'll help other readers.
Yes, I suspect - but don't actually know - that the Day & Night Water Heater "registration no" shown is or was equivalent to a serial number, perhaps registering the heating elements?, and was data that would have been entered in a warranty registration.
Your Day & Night Jetglas Jupiter-model water heater was the product of William J. Bailey's Day & Night heater company..
For most electric water heaters, one of two standard water heater element designs can usually be found in a generic form that will work just fine.
See ELECTRIC WATER HEATER ELEMENT REPLACEMENT
On 2022-01-21 by ned
I have a Jetglas JRD-2 30 gallon electric water heater and the only label I see (at about chest height) has a registration number on it, is that the same as the serial number? This heater is very old, possibly from the early 1970s.
Reg # 430866 564593
The heater is having issues making hot water, so I am trying to test the elements to see if they are working or not (one out of two is, apparently). The elements are 4500 watt, max amp rating of 21.7.
Are there standard elements that can be swapped for the old ones? Thanks in advance for any info.
[Photo of Day & Night Jetglas water heater data tag - above]
On 2021-01-30 by (mod) - Gas fueled Day & Night heater won't stay lit.
Not necessarily, Roberto; A pilot light problem doesn't mean the heater is at end of life;
Try replacing the thermocouple - details are in
THERMOCOUPLE REPAIR / REPLACEMENT
On 2021-01-30 by Roberto Amaya
Pilot light will not remain lit. Unit is approximately 20 years old from date of inspection for installation.
Time to buy a new water heater?
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