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 Hot Water Heater
Author: topo0323 (TN)

We have a 10 year old hot water heater. Last week the floodstop shut off water to the house after the pressure relief valve spewed water into the floor. We called a plumber from a Google search. He came and looked at it, said it was a bad pressure relief valve, replaced it and eas gone in 20 minutes and charged $120. The next day the hot water got extremely hot and the breaker ended up popping on the hot water heater. I decided to test of myself because what he did didn't sound like it was fixing the problem. I find that the bottom element was bad. So, long story short, I drajned the tank and replaced both thermostats and both elements from a kit from Lowes (figured I'd just knock it all out while it was down) then I vacuumed out the bottom of the tank with a shop vac and did notice quite a bit of build-up. Hence the bottom element burning out. Fast forward to today and the hotwater heater spewed again and the floodstop shut down the water again and the tank had overheated again. The breaker didn't pop but the reset on the tank did pop. So I'm at a loss. What could be causing the tank to overheat? It's set at 120° on top and bottom as well. Could the breaker be overloaded? It's on a sub panel with 3 other things. The only thing that's changed recently in the house is a remodel on an upstairs master bathroom that was renovated professionally and an additional vanity was added and a new tile shower with dual showerheads. I just don't want to be misled again. Can anyone help? I don't know where to go from here but am leery of calling a plumber until I'm more educated. Thank you.

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 Re: Hot Water Heater
Author: North Carolina Plumber (NC)

The breaker should not have tripped just because the water heater overheated, so you've got an electrical issue there. Are you positive the thermostats are wired correctly ? That the bottom element only receives power when the top thermostat is satisfied ? Have you turned the thermostats up and down, heard them click and verified that the power is being turned on and off to the elements when it should ?

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 Re: Hot Water Heater
Author: topo0323 (TN)

Should only one element be heating at a time? I haven't tested but if I run a test and they are both on, would that be the probable cause?

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 Re: Hot Water Heater
Author: hj (AZ)

Well, the elements in those kits are the poorest ones made, and I have seen them fail in a matter of weeks. You are describing what happens when one of the elements shorts out. When you start replacing thermostats, however, it is possible to miswire them if you just duplicate where the wires are attached on the old one, because there are two models of thermostats and they are wired in different ways.



Edited 1 times.

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 Re: Hot Water Heater
Author: topo0323 (TN)

I'll look at the wiring diagram again but I did take pics and wire it back the way it was. It's flipped the switch on the hot water tank again about an hour ago. The water in the task is getting too hot. Thanks for your help. I'm at a loss on this one.

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 Re: Hot Water Heater
Author: hj (AZ)

IF you have a different "pattern" thermostat, you have to wire according to function, NOT like the old one was wired.

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 Re: Hot Water Heater
Author: North Carolina Plumber (NC)

One of your elements is receiving power after the thermostat has been satisfied. The top element receives power first, and when it has got the temp up to the setting, it switches off and sends power to the bottom element, and when it gets up to the temp setting it will switch off.

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 Re: Hot Water Heater
Author: topo0323 (TN)

This thermostat looked identical to the one that was one it so I just assumed it would be wired the same. The dial, the screw layout etc were all the same. That may be where I messed up. Not sure BUT this thing tripped long before I replaced anything. It initially shot out of the relief valve for some reason and tbe tank had not been touched.

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 Re: Hot Water Heater
Author: topo0323 (TN)

I think that is what's happening but I don't know what changed to make that occur. This happened the first time and nothing had been replaced. It just shot out of the relief valve and the Floodstop shut our water off. So sommething happened to start this reaction and I cannot seem to figure out what that is. Water is extremely hot again tonight. I just turn the breaker off to keep it from getting too hot overnight and possibly doing more damage.

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 Re: Hot Water Heater
Author: PlumberLoren (CA)

With a 10 year old water heater I would consider replacing it. Do you know a good electrician? I think you might want to hire him for the price of a service call to make sure everything is according to code electrically.



Edited 1 times.

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 Re: Hot Water Heater
Author: hj (AZ)

The letters on the various terminals is what determines HOW you connect the wires, and some t'stats have A, B, C, and D in a different arrangement.

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 Re: Hot Water Heater
Author: topo0323 (TN)

So, plumber comes today, tests and says it looks like one of the elements I just installed is bad. He did say it was wired correctly. He drains tank (scalds his hand from water doing so) ... replaces both elements. Fills tank back up. Turns on power and tests elements. Everything seems fine. 4 hours later water is boiling again. I guess there's somethings even the professionals can't figure out.

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