Water heater was not providing hot water. I replaced elements after
testing showed resistance was out of spec (6 ohms instead of 10-15).
Still no hot water. Check voltage coming into heater with Simpson
Analog meter. Reading is 0 volts between the two wires, but about 115V
from each wire to ground (the tank).
This seems like I must be getting the same (in phase) 120 V power to
each lead instead of the separate (180 degree out of phase) power
The wiring has not changed!
I do notice that the circuit breaker for the water heater is "soft".
It does not have the snap and spring tension of other similar breakers
in the box.
Is it possible for a breaker to fail in this way?
Thanks for any help.
Sounds like one leg is open, either in the wiring or in the breaker.
If you feel competent enough, pull the panel cover and measure
the two hot lines at the breaker. This should help you diagnose
it. Do NOT do this if you're not familar with the procedure and
are the least bit wary doing it.
Yes, a breaker can fail in this fashion, and if it has, the panel
cover will have to be removed to replace the breaker.
That of course is assuming he's measuring it with the feed wires
connected to the heater, which seems reasonable, as it accounts for
the readings. Also, if he's measuring the resistance of the elements
without disconnecting, then he's probably reading both elements in
parallel which is why he's getting about half what he's expecting.
I did not have the feed wires disconnected when checking voltage on
I see how an open leg could cause my reading since (assuming the
thermostat was working) there would be a circuit (including the
element) between the feed leads.
I did however test the element resistance with one wire disconnected.
So I was getting the same phase 120, because it was from the same lead
by way of the circuit through the element (and not from the breaker).
I'm embarrassed that I missed this.
Thanks Leroy and trad.
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