Anybody ever seen one of these? “Clark Electric” Automatic Hot Water Heater. Trying to guess the age. Looks like maybe 1989 by the tag. Has no TPR valve what-so-ever. and intermittent asbestos covering on the hot line out. Im a student inspector for now and am wondering how to write this one up. Lack of a TPR is definitly a red flag.
Well the latest patent date was applied for in July 1939. Normally patents last 20 years. Had there been changes to the design, a new patent would most likely have been applied for. Any other pictures besides the label? A full width and height photo?
Its a water heater NOT a Hot water heater .
Why heat hot water?
…because it is not hot enough? 
At 1500 watts, it would have to be hot water going INTO this unit. That’s the same wattage as a hair dryer…time for replacement.
We lived for years with 1,000 top and 1,000 bottom only one was on at a time.
40 gallons is a lot of hot water .
Being your a student inspector let me pass on a bit of info to keep the old plumbers from laughing at you as they did me when I was a pup.
You need to leave off the word HOT when refering to water heaters as they are not hot water heaters you don’t heat hot water you heat cold water, pardon me but this is my humor for the day:p:p:D
I’ve been a licensed plumber for twelve years, and no, plumbers don’t use the word “hot” before water heater. but, we also don’t say toilet. it’s a water closet. Anyway, although this is not the professional way to say it, it is actually very accurate. Think about how much time a “tank” style appliance is actually heating already “heated” water! This used to get people smacked when they said it in their apprenticeship! Now, that I am the one to do the smacking, I just yell a little bit and say they better be comparing it to a tankless! 
tankless! I call them thankless
Thankless water heaters .
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http://www.youtube.com/watch?v=vffdymvjluk .
This is a you tube clip and it is quite amusing unless you sell tankless water heaters.