I had a halogen light there for a whlle, but the socket on one side burned out, or got hot and crumbled. I didn't even think about efficency when it was installed, or when I replaced it. Shame on me.
I ended up getting an led fixture that rates itself twice as bright as the url I gave in the OP. I'm not going to say what it is, because I've learned from experience that one or more people will tell me it's no good, and I don't want to hear that now, since I've already bought it and may put ii in any minute now.
Thanks for the informative reply. For the sake of electricity, I'm glad I didn't get incandescent this time. Maybe no more lightbulb changing.
(I hope to go away for a few weeks next february and I didn't want to wait until spring to fix the lights.)
True. But otoh, the appliance is rated in watts. People have to keep track of their own time, the time they keep the tub hot, which is presumably the same no matter what the voltage.
Is this perhaps a gas water heater? When I took my electric water heater apart, it had a steel shell but inside that was a flexible plastic of some sort, milky clear/white, with maybe glass embedded in the plastic. It was 1/4" thick or more and was never going to break, because I pulled it away from the metal and bend it 60 degrees and there was no cracking.
It was sold by Sears but seemed identical to the one that was first in the house, by A.O.Smith. (I'm not positive it's labeled glass-lined but people make it sound like all of the tanks are.)
When I brought it home I worried about dropping it, because I had heard they were lined with glass, so I thought they would be fragile, but like I say, it would have been impossible to break the glass.
Mine is electric. See: "What's inside a hot water heater?" The video showing the inside of the tank start at about 4:30. As far as I can see, it's just a steel tank with some manner of plating on the inside. That's roughly what I found when I sawed apart my original water heater, except that there was much more rust and lime accumulation. Also, if there were a soft plastic inside liner, I would expect it to melt from the heat of gas flame at the bottom.
Here's collection of AO Smith residential gas water heater data sheets: I checked a few and most offer variations on the glass lining such as: "BLUE DIAMOND ® GLASS COATING An A. O. Smith exclusive provides superior corrosion resistance compared to the industry-standard glasslining"
Yes. It requires a heat spreader between the cup and the flame. Apply the flame directly and the hot spot will burn a hole in the styrofoam.
True. However, a gas water heater has to deal with stratification, where the water is much hotter near the flame than near the tank outlet. I couldn't determine how much of a temperature difference by Googling. You're probably correct that it won't melt if it's decent plastic, but I'm still suspicious. Unless secured to the steel tank, it might soften, warp, bend, buckle, or otherwise provide an excuse for water to get to the steel. From there, it's only the anode rod that protects the steel tank from corrosion.
Well, let's do the math. Coefficient of linear expansion for: steel = 12*10^-6 m/m-K alumina = 5.4*10^-6 m/m-K
From 25C to 100C (near the burner) on a 2 meter high tank, the steel will expand: 12*10^-6 m/m-K * 2m * (100-25) = 1.8 mm and the ceramic: 5.4*10^-6 m/m-K * 2m * (100-25) = 0.8 mm
1mm difference doesn't sound like much, but if both materials are rigid, it could easily delaminate. The alumina ceramic is very rigid, but the steel can bend. If the tank were allowed to bulge slightly in the middle, it would work, if the alumina can survive being under constant tension without cracking.
BTW, I learned that you can saw though the outermost rather thin steel layer of a water heater (the part that you see) with a reciprocating saw, even if the blade no longer has any teeth. They all wore away but it still cut fairly well. Certainly it wasn't worth changing the blade.
I woudn't call it soft. It bent, but it wasn't flimsy. Maybe the stiffness was a little greater than a bicycle tire.
I wanted to check if my water heater was advertised as glass-lines, so I started looking on the web. Then it dawned on me that a better way would be to look on the water heater, which probably still has labels on it. (Yes, it has several.)
And the top label includes "Cobalt Blue Ultra-Coat (or Cote) Glass Lining." but I'll bet you any money that this Kenmore water heater is built just the same as the last one, with the 1/4" (or slightly less, not more like I said.) layer of clear/milky vinyl?, something like plastic milk cartons would be if they were thicker, probably with glass mixed in, because otherwise t hey couldn't say "glass lining". Or maybe it's largely crushed glass in some "plastic" medium.
I think Kenmore is AOSmith because the intake and output pipes are exactly the same distance apart as the wh that came with the house (when no other brand I looked at had that. I'm compulsive. I didn't want to use flexible and I didn't want zig-zag piping. ) And the front panels were the same (although maybe they all use the same thermostats and heaters.) Basically everything looks the same as the original.
Charlie+ wrote in news: snipped-for-privacy@4ax.com:
Over in the UK they tend to be copper or stainless and maintenance free lifespans of 40+ years are not unusual. e.g. Albion brand stainless hot water cylinders dont use any anodes and have a 25 year anti-corrosion warrenty on the tank. The immersion heater element circuit should be RCD protected, both for safety and so that any insulation failure will be detected before significant electrolytic corrosion can occur.
Whoever first introduced vitreous enamel-lined mild steel hot water tanks to the American market did you all a great disservice.
ALso plastic doesn't conduct heat all that well, leading to an inefficient WH. Also a gas HWH has a pretty powerful burner, mine's rated at 40,000 BTU/hour input. I suspect you suspicions about the plastic buckling/warping and separating from the steel tank are correct.
No, no. You don't want any thermal conduction through the plastic liner. The whole idea is to keep the heat inside the tank, not radiate or conduct it to the outside. That's why there's a mess of fiberglass insulation between the steel water tank and the outside cosmetic steel cover. Some people add an additional water heater insulating "jacket" on the outside of the heater. A thermal insulating plastic layer between the water and the steel tank should improve efficiency.
An easy way to tell if your water heater is a piece of junk is to measure the case temperature of the water heater. Use a contact thermometer (Thermocouple or thermistor, not optical IR). It's probably the worst at the top of the heater. If the outer case is warmer than the ambient air, you're wasting energy heating that atmosphere instead of the water. Same with a refrigerator. If the case of the fridge is colder than ambient, you're cooling the kitchen.
That was just a guess. I'm not so sure any more. The plastic liner and steel tank are both fairly flexible, so they can bend and bulge without breaking anything. You'll never see it because it all happens inside the tank. If they're glued together (bonded) properly, I don't think they will come apart. I was wondering why the water tank didn't have stiffening ribs, which would allow the use of thinner steel. I guess(tm) stiffening might interfere with the necessary flexing of the tank with temperature.
It should also be possible to dope the alumina ceramic coating with something to help it match the coefficient of thermal expansion for the steel. Even so, stratification, and the difference between temperatures on both sides of the steel tank, will create enough of a temperature gradient to possibly microcrack the ceramic.
Incidentally, it doesn't take much movement to wreck a ceramic coating. I had a nice ceramic coated steel tea kettle that I usually heat on the kitchen stove top to about 180C. One day, I stupidly put it directly on top of my wood burner running at about 300C. I compounded the error by boiling off all the water. My first indication of a problem was the sound of something like popcorn from inside the kettle. That was the inside coating flaking off and bouncing around. As I approached, a large piece of the outside coating flew off in my general direction. I had to use a broomstick to remove the kettle. I haven't calculated the differences in expansion, but for something as small as a kettle, it was much smaller than my predicted 1mm.
There are numerous Sears manufacturers lists available online. Many have missing prefix numbers or only include specific classifications, such as power tools. If you can't find your model number prefix, just try a different list:
On some serial numbers, you can extract the date of manufacture:
Incidentally, the above web site has some rather interesting photos of appliance related fires. For example, hot water heaters do NOT start fires: and portable electric heater misuse hazards:
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