Rheem 40gal not heating

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Mystery1982

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I have a Rheem 40 gallon water heater it's got power from the breaker box all the way through the top thermostat the elements and the bottom thermostat I just replaced both elements but for some reason the water is not getting hot both top and bottom elements are 4500w/240v I also replaced the electrical wire and a new double 30amp breaker. What could possibly be the issue
 

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Plumber69

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You should have 240 at between terminals on top element first. If not then see if you have 240 going into the top thermostat. If you do at thermostat, check to see if that red button tripped.

wh-reset-button.jpg
 
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Reach4

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I have a Rheem 40 gallon water heater it's got power from the breaker box all the way through the top thermostat the elements and the bottom thermostat
Do you read 240 volts across the top pair of terminals on the thermostat?

Do you read 240 volts across the terminals on the top element?
 

Mystery1982

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You should have 240 at between terminals on top element first. If not then see if you have 240 going into the top thermostat. If you do at thermostat, check to see if that red button tripped.
I've checked the thermostat breaker it's not tripped I have 120v on each side of the top terminals on the thermostat but when I try to test them together I don't show 240 like it should but the current is there for each side.
 

Reach4

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I've checked the thermostat breaker it's not tripped I have 120v on each side of the top terminals on the thermostat but when I try to test them together I don't show 240 like it should but the current is there for each side.
Power is not making it to the terminals. You would get that same symptom if one of the two hot wires was broken, or disconnected, or even entirely missing..
 

Mystery1982

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Power is not making it to the terminals. You would get that same symptom if one of the two hot wires was broken or disconnected.
It's a brand new wire and double 30a breaker is it possible to be the breaker box?
 

Reach4

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It's a brand new wire and double 30a breaker is it possible to be the breaker box?
Can you probe the two wires in the breaker box at the 2-pole 30 amp breaker? If you don't have 240 across the two wires at the breaker box, the problem is in the breaker box.

Turn the breaker off completely and back on. Do you have 240 then? I wonder if the breaker had tripped.

If still bad, show us a picture of the 2-pole 30 amp breaker and the wires.

If you don't have 240 across the two wires at the breaker, and you reset the breaker, and if it is a proper 2-pole 30 amp breaker, I suspect the breaker is bad or one of the wires connected to the breaker is shorted out.
 
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Mystery1982

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Can you probe the two wires in the breaker box at the 2-pole 30 amp breaker? If you don't have 240 across the two wires at the breaker box, the problem is in the breaker box.

Turn the breaker off completely and back on. Do you have 240 then? I wonder if the breaker had tripped.

If still bad, show us a picture of the 2-pole 30 amp breaker and the wires.

If you don't have 240 across the two wires at the breaker, and you reset the breaker, and if it is a proper 2-pole 30 amp breaker, I suspect the breaker is bad or one of the wires connected to the breaker is shorted out.
I'll check that out tomorrow I have another breaker box I can try thank you for the advice I'll post an update.
 

JerryR

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What do you read across the top heater element? If it’s 0 when water is not hot then the top thermostat is defective or one phase is missing.

If you read 240v between the top heater element contacts and water is not heating then that element is Defective, open or the red over-temp button is tripped on the upper thermostat.

You will ALWAYS read 120 v to ground on each screw contact heating element no matter hot or cold water.

Water heater thermostat only switches On one leg when calling for heat. The opposite contact is always hot.
 

JerryR

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I think he is measuring across the top of the thermostat -- incoming power.

I reread it and now I got it.

He’s missing one incoming leg if he’s reading 120 v on each yet 0 V across both inputs.
 

Master Plumber Mark

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Unless you have a leak on the hot side of the system in the slab or crawl space,
you would be wise to just go out and buy yourself an upper and
lower thermostat and simply change them...... sometimes those things just go bad
and you end up chasing ghosts in the system for days on end and they
are almost impossible to chase down ......

dont be ashamed about it....
just change it all out and you have hit the home run.....
 

Mystery1982

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Unless you have a leak on the hot side of the system in the slab or crawl space,
you would be wise to just go out and buy yourself an upper and
lower thermostat and simply change them...... sometimes those things just go bad
and you end up chasing ghosts in the system for days on end and they
are almost impossible to chase down ......

dont be ashamed about it....
just change it all out and you have hit the home run.....
After an entire day spent tracking down the problem I took your advice and replaced both thermostats and it worked when all else fails replace it all it was still cheaper than buying a new water heater thank you for the advice and help from everyone.
 

Master Plumber Mark

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I have to do this all the time, and I am really over being ashamed of it....
.and sometimes customers complain to me about not knowing what the hell I am
doing and I am chargeing them for extra parts that they dont need........
I normally tell them that I will do a half way
job and gamble on being correct, if they wish me to and save them 10 bucks, ---------
but if I have to come back because I did not change a 10 dollar part that you fought me over
their will be another 125 dollar service charge you will have to pay again..........

that normally singes their bungholes just enough to let me do a 100% changeout....
and everyone goes home happy
 

Reach4

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After an entire day spent tracking down the problem I took your advice and replaced both thermostats and it worked when all else fails replace it all it was still cheaper than buying a new water heater thank you for the advice and help from everyone.
Good that it's working, but a bad thermostat could not explain why you did not see 240 coming in.

An independent-trip breaker that was broken on one leg only could explain it, and then at some point you reset the breaker. That's why I had suggested a picture of the breaker.

An intermittent supply connection could also have explained it.

Probing the wrong pair of terminals plus a bad breaker could certainly have explained it.
 

Mystery1982

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Good that it's working, but a bad thermostat could not explain why you did not see 240 coming in.

An independent-trip breaker that was broken on one leg only could explain it, and then at some point you reset the breaker. That's why I had suggested a picture of the breaker.

An intermittent supply connection could also have explained it.

Probing the wrong pair of terminals plus a bad breaker could certainly have explained it.
The issue with the 240 was that it was an old breaker box luckily I had another breaker box that was new once I switched to that and replaced the thermostats I had full power all the way through. I essentially replaced every thing except the water heater itself
 
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