I'm not getting any power to my upper thermostat, but checked the
breaker and have 120 and each pole there. I checked the top of the
heater, where the wires come out of the wall and attach to the wires
going into the heater, and I get 2.5 volts coming out of the wall.
Any thoughts on where/what happened?! Do I have to dig through my
walls?! FWIW, I'm in Tampa, FL area, home of massive lightning, which
we had yesterday, but only noticed no hot water today, after two
people showered okay. Possibly they had enough hot water even if it
went out yesterday? But still, I have power out of the breaker...?
I am far from an expert on electric water heaters. I do know that they are
designed so that both elements can not be on at the same time. Because of
that you may not have power to the top element or the bottom at a given
point in time.
I doubt very much that the wiring in you walls has failed. You should be
able to verify 220 to the disconnect box near the water heater.
I suspect you had one dead element and the other failed in the last day or
so. Good news is that replacing an element or even a pair of them is fairly
simple on most units provided the water cut off will shut of the supply.
Thanks for the reply, but the top receives power first. I just
replaced both thermostats and heater elements about 6-9 months ago.
The wires that I'm testing for power, and receiving 0, are coming to
the upper thermostat from the top - the top two terminals. But really
moot, since I'm not even getting more than 3 volts from the wall into
the top of the heater (is the 2.5 odd? - multimeter set on 200 AC).
Don't have a disconnect box near the heater, unless that's what I'm
referring to as having checked and gotten 2.5 volts. It's simply a
small concave part of the top of the heater, wherein the wires coming
from the wall attach to the wires going into heater.
The first thing you need to check, is that you have 240 volts across the two
poles of the breaker. If one leg of the breaker is bad, you'd still get 120
volts from each of them to ground. Once you've determined that you do have
240 volts at the breaker, you can move on to step two.
I am guessing you have a 240 volt water heater. You must be checking from
each side of the breaker to the ground or neutral to get 120 volts. Go
across the two wires at the breaker. YOu should have 240 , but may not be
showing any voltage, or some very odd low voltage. If so , one side of the
breaker is bad or tripped. The reason you show 120 volts on each side is
the voltage if feeding through the water heater and that is where it is
On Fri, 14 Aug 2009 17:43:07 -0500, "Ralph Mowery"
Thanks. I just re-checked just to make sure, and still the same,
although I did confirm that it's 240 between both poles. Actually,
fwiw, it's 237, and going from each to the neutral is 118 and 117 (I
think; could've been 118 and 119). But, clearly not zero.
I was measuring at the breaker by touching the screws, but thought it
possible that the wires weren't screwed in tightly. I tried testing
behind the screws, but couldn't get a reading. Am I right that
touching the screws won't necessarily give me what's coming OUT of the
breaker? I wiggled, or tried to, the wires, but didn't note any
looseness, and re-checked at the heater, still with no voltage.
I guess next step is to undo and re-attach the wires at the breaker?
Haven't done that yet, and hesitate to if not needed.
I IMAGINE this is unrelated, but now no 24 volt to my A/C thermostat.
We had problems yesterday, which happens a couple times a year, but in
all previous instances i get an error code on the thermostat,
indicating there's a problem with the 24 volt line. Now, there's NO
power to it? fwiw...
With the breaker off disconnect the wires where they enter the water heater.
Turn the breaker back on and see what you have there. The reading should be
about the same if not exact as what you have at the screws.
A ruptured element can send the entire load to ground. A bad thermo or
whatever inside the heater can distort the readings.
If you have 220 or 237 coming out of the wires at the heater then you know
the problem is within the heater. Sadly some new parts fail faster than
older ones so don't assume they are good because they are only six months
For the benefit of others do post back your final results in the same
That's what I had done previously. I got 0 (2.5 v.) at the wires. I
detached them from the wires going into the heater, and tested the
wires coming from the wall. So, it seemed like the only issue was
whether testing at the screws was accurate, or if the wires might be
loose from the breaker out.
The power from one pole can show at both screws, so both
being 120 to ground doesn't mean much. My gut sense at this
moment, you may have a bad aquastat, and you're getting
power to both sides of the element from one pole of the
power. Check to see the element is getting 240 VAC. I mean
On Fri, 14 Aug 2009 20:39:43 -0400, "Stormin Mormon"
I'm not even getting 237 v. to the upper thermostat, which receives
the power before it gets to the elements. I only get 237 v. out of the
breaker (at the screws; when breaker is off, it's 0, hence that is
indeed my output). But as soon as it's coming out of the wall at the
heater, it's 0.
There is no use to worry about a couple fo volts differance.
Cut off the breaker and test to make sure the voltage is really off.
Switch the meter to ohms and see what the resistance is to the heater. It
should be very low on the two wires and almost an open circuit to the ground
wire. If the resistance is low on the two wires in the breaker box comming
from the heater, the breaker must be bad. If it is almost an open circuit,
go to the heater and measuer the resistance of the wires going to the
breaker. If low, you have a bad wire. If high, the element is probably
open, you can measuer that.
You may also want to make sure the power is off, then hook both hot wires to
the ground at the water heater. Then go to the breaker box and check each
wire to ground. If one is low and one is ooen, you have just found your
open wire and will have to trace the wiring and maybe replace or splice it.
On Fri, 14 Aug 2009 20:19:55 -0500, "Ralph Mowery"
Thanks for the great, specific advice! In exchange, I have a feeling
I'm going to be asking a stupid question.
So, I turned the breakers off (two 30 amp ones), and pulled the wires
out of the breakers to measure the resistance between them. Right? I
get 1. Likewise, when testing from each wire to the neutral bar
holding all the white wires, that earlier I used to measure the 120 v
coming into each main wire to the box.
I went to the heater, and also measured the resistance between the
same wires coming out of the wall, and also got 1. likewise when I
went from one of the wires to a ground (metal part of the heater).
Did I do this right? what does this tell us? Sorry for my ignorance,
and thanks so much for the help.
UPDATE: LOL... okay, very well could be some "user error" in place
here; what a shock, huh? I replaced both breakers, just in case. I get
120 between each and neutral. Went to where the wires came out of the
wall and joined with the wires going into the heater... and realized
that one was white (flesh tone), and the other black. Duh... So,
obviously the black is coming from one of the breakers; not sure
where the other black goes into the heater, but it isn't this
off-white one coming out of the wall.
Still no reading between the black and off-white wires coming from the
wall; 120 between the black and ground; nothing between off-white and
A Black and Red wire are attached to the top two poles of the upper
thermostat, coming in from above. No voltage between them. This should
read 120 or 240, depending on system, right? I do get 120 between each
pole and ground, though.
Pushing the reset button does nothing, so it apparently wasn't
Does the lack of voltage between the two top poles, L1 and L3,
indicate a bad thermostat and it's as simple as that?!
Okay, replaced the upper thermostat. Still no reading between L1 and
L3; should there be? Still 120 from each pole to ground.
No reading between the upper element contact screws, so no power is
getting there. Another bad thermostat? I'm stumped (but that doesn't
That symptom indicates the two legs (red and black) are from the same
phase instead of from the two alternate phases. That's a miswiring
somewhere that connected them both to the same side of the 240V breaker.
I've not followed this thread; just amazed this AM it was still alive
(and seemingly well) so glanced at your response here--did you
disconnect something looking to trace the power earlier? It would seem
perhaps if so that would be where it got crossed up when put back altho
just what would be where w/o two leads on one terminal is puzzling.
Unless there were pigtail connections, would be possible to have
inadvertently connected the two together. If it's been wired this way
all along it never would have had an upper element working.
Trace back from where the two power leads have the 120V and eventually
you'll find they're connected to the same side of the 240V supply.
Wherever that is, split them back apart and get one to each side.
You'll then still see 120V to ground but 240V relative to each other.
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