I'm trying to fix the "hot dry" function on my dishwasher--as is, I get no steam, no heat, and no drying. After seeking some advice, I removed the heating element and tested its resistance with a multimeter. It said 0 OHMs! I figured it was broken and got another, but that says 0 too!! Does this make sense?
Dishwasher heating element
Jun 10, 2006
13 Replies
0 ohms means that it is good and that you shouldn't be doing the repair yourself.
Hi,
0 Ohm means the element is not open.
If the elements were _really_ 0 Ohms then it would mean that both were defective but in a completely shorted way. More likely you had your meter on the wrong resistance range or, if it was on the lowest range, that the meter doesn't go low enough.
The problem is in the wiring or a connection or the circuit element(s) which are responsible for switching power to the element and I'm guessing that a repair is probably not something you should see as a do-it-yourself project.
especially somebody who doesn't understand electrical resistance.
HEY We all had to start somewhere! I have made lots of dumb mistakes fixing things, and I am a service tech for over 30 years!
Cut the guy a break!
Have you checked for power at the heater when the machine is running?
Oh, the visual of this taking place with a complete amateur. Door open, water spraying, and arms reaching in with test leads. Honey, will you hold the meter while I check this please.
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I don't think I've done that but I've reached in to turn the water off to a water cooler when it was plugged in and the fan was running.
(prior to this we usually had it unplugged, but we thought we were done and plugged it back in! I didn't really hurt myself)
I agree with you that everyone makes a lot of dumb mistakes. When I was president of my hiking club, I told people that any hike where everyone came back alive was a success.
don/'t let this bother you. It's like learning to walk. A baby has to fall down a few times, many times, to learn how to walk.
Your reasoning made sense if this had been a motor or even iirc a lightbulb or just about anything other than a heater. Heaters use a lot of current. Much more current is needed to make heat than to make motion or light, so the resistance has to be a lot lower. fairly close to zero, to let all that current flow through. (one tends to think that it would have substantial resistance, and the electricity would fight its way through like the US Army at the Arno river, and this fighting with the resistance (whatever that means) would make the heat, but that's not the way it works, not the right analogy.) OTOH if the resistance were really literally zero, too much current would flow and things would melt.
But the real clue was that the heating element you tested was U-shaped, right? That is, one end was separted physically from the other end. (I-shapped heating elements like in toaster ovens are the same thing, topologically.)
So there really can't be a short circuit that would make the resistance go to zero. There could be an open circuit, but that would make the resistance infinite. But if say, the heating element has a wire coil in it, the most that could short would be two adjacent loops. Out of maybe 100. So the resistance would go down 1 percent. Or 10 out of 100 for 5 percent. But the first loop can't short against the last loop, because it is probably 18 inches away via the curve of the heating element. I'm not explaining this well, but do you see why when one end is an inch away from the other end, through empty space via a straight line, there can't be a short circuit that would result in zero ohms?
OTOH, if you had a lamp or something with a cord coming into it, through a rubber grommet, and the grommet fell apart, and the metal that surrounded the grommet cut into the cord and connected the two wires which were only a quarter inch apart, that would cause a short with infinitesimal, almost zero resistance.
Light bulb is a heater...its a pure resistance...the same as a heating element
Light bulb is a heater...its a pure resistance...the same as a heating element
Narural selection at its best! At least the person knew enough to come here and ask for help!
OK, but it's a tiny heater. ;-) It's designed to give light and although maybe half of the energy makes heat, one couldn't heat the water in the dishwasher with the heat from one lightbulb, unless it was maybe a 1000 watt bulb.
I think one tends at first to have the same misconception I refer above wrt lightbubls too. That the brighter bulbs have higher resistance, because that means the electricity has to fight even harder to get through it, and that makes more light. But in fact the brighter bulbs have lower resistance, and more current flows, and more light is made.
no they don't.
Simply put, ohms law is E=IR. E is voltage in volts, I is current in amps, and R is resistance in ohms. Or I=E/R; same equation. Power is P (in watts) = IE, or (E/R)*E, or E^2/R Power is inversly proportional to resistance.
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