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Old 12-31-2012, 03:19 PM   #1
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120v water heater

I recently purchased an electric point of use water heater. I could have ordered it in three voltages. 120v , 220v, or 277v. I ordered the 120v 30amp model.

The instructions are TERRIBLE. The instructions read as follows. Wire as per diagram. Thats it. The diagram shows three wires coming from the unit labeled L1, L1 and ground symbol. They generically come from the bottom of the unit pictured in the diagram. Yeah...its that bad, so dont ask for anymore info because there is none.

Ok now on the wires themselves there is a black wire with a tag labeled "Neutral". There is a red wire with a label named "Power"...and a grean/yellow wire labeled "Ground". This would appear to be 120v correct? not 220v?

Anyway, my outlet is wire and tested at 124v so I'm good there...a hot, neitral and ground in the 30amp outlet.

What am I missing? Is it possible the unit requires two 120v hots? Is the unit labeled incorrectly and the neutral and hot are mislabeled (swapped)? Help please. I don't want to go on a wire connection expedition.


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Old 12-31-2012, 03:22 PM   #2
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Well, it seems as if the black is the neutral, the red the hot and the green the ground. Not typical, but you have to go by the labels.
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Old 12-31-2012, 03:46 PM   #3
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Yes I ran 10/2. Its a 30a water heater. I believe its wired correctly. I just found a link on the website for the water heater and it says its single throw 30a breaker. Im pretty sure I have everything wired correctly. So why doesnt it work?

What happens if a 220v unit (ie 2-120v legs and a neutral) was swapped by mistake by the company and I am only running 120 through a 220v unit? Will it still turn on but heat only half as much?

What happens if the "power" wire and the "nuetral" wire were mislabeled?
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Old 12-31-2012, 04:10 PM   #4
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If its such a piece of junk then maybe the element is defective. Have you checked the resistance? Posting the manufacture and model number helps too.
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Old 12-31-2012, 04:15 PM   #5
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If it's actually a 240V unit, it would heat 1/4 as much on 120V. You would probably notice it working, but it wouldn't work well. If the hot and neutral labels are reversed, it should function normally (but there could be a safety issue). You'll need a clamp-on ammeter to measure current to figure out what the problem is. It could be that the flow switch is not sensing water flow and turning the unit on.
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Old 12-31-2012, 04:19 PM   #6
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Even the worst piece of junk should have a UL (Underwriters Laboratory) plate on it specifying the voltage, amperage, and probably wattage for the unit. Also a serial number, manufacturer's name, and possibly a date of manufacture. So check the plate and see what it says.
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Old 12-31-2012, 05:02 PM   #7
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You did fill it before you turned it on correct?


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