A 20-gallon water heater is a pretty large thing to find under the kitchen sink. Before anything else, I would relocate the heater, if possible. If not, I would certainly make sure that the outlet of the T&P went to a place that should receive it.

So, this is a bit unusual, but you are talking about a valve that trips with either excessive pressure or temperature. Since the unit is new, you probably can get a free replacement on the T&P valve, which will fairly eliminate any concern that the device is defective. Even if you have to buy one, that would be the right thing to do.

New tanks often contain the instruction that an expansion tank be put in parallel in the COLD supply line. Expansion due to heating is normal, but it must have a place to go. (Municipal systems with no check valve or Pressure Regulator Valve can accept the expansion.) Otherwise, unless another path is provided, it will flow to the T&P.

Because the tank was new, all its water was COLD. In a tank that is just replacing the HOT water used, the degree of expansion would be considerably less. So it is possible that, had you drawn water before the six hours, the amount of trapped water would have been relieved.

Pinoke

Unfortunately relocation isn't an option. I did some dishes and ran some other hot water to give it a little of an outlet. But, we ran some errands and got back home and it had happened again. The thermostat had kicked off and the TP valve had reset itself. So, no major catastrophe, just some water on the floor. I went ahead and reset the thermostat to get the heater to kick back on. We'll see what happens this time.
Next question, where is the check valve or pressure regulator valve? I'm fairly ignorant to these things and don't mind checking the pressure coming into the house etc but I don't have any idea where to look to find it. Our water cut off is out by the street in front of our house but I don't really know where to look from that point. Let me know what to look for and I'll try to find it. We've got a local plumber that might be able to find it as well as check the pressure in the line. Is this something that the city might do as well? I live in a small town and we know many of the people that work for the city. Thanks, Greg

Yes. A small town is the best town in the world. The sincerity of city workers is just the kind of help you need. Ask them to verify that you have or do not have a pressure regulator. It would be at the meter, more or less. That is, before any outlet.

I do believe in DIY. But maybe you could use a bit of help. You could pay a fee for information and then do the work yourself. YouÂre almost there.

Pinoke

I'll get there. I just noticed that I've got the thermostat turned all the way down to 90 degrees. I just ran some water out of the hot water faucet and it was at 150 degrees. Would that make a difference? I think the TPR valve is rated for 210 so it may not matter. Thanks again, Greg

IÂve purposely ignored the temperature, because it is a factory control which is not changeable in the field. If this is the cause of your problem  that the temperature setting is not controlled  it is a matter for the manufacturer, via your dealer. It no longer is about your installation.

This amount of temperature difference is too great to be a transient reading error. If you believe your information is correct, you need to take this up with the seller. Such a unit will never be a reliable appliance in the home.

This is one manÂs opinion. Please consider all kinds of input and then ask your supplier what you should do about it.

Pinoke

Had the local plumber check it today. The water pressure coming into the house is 45 psi. We again checked the temperature of the water and it was right around 150. So, I replaced the thermostat, put the plastic cover and insulation back over it then put the cover on. It should be fitting nice and tight on the tank so as to get an accurate reading. I'll post here in a bit and let you all know what the temp. does. Thanks, Greg

Didn't mention it earlier but got to thinking about it and thought it was strange. There is an "extra" 120 volt line running from the other side of the cabinet to the heating element. No idea why its there but I just traced the line and all it is, is a plug thats plugged into an outlet, run through a small hole in the cabinet and attached to the water heater. It looks like this connection was keeping the element running all the time. After disconnecting this, the thermostat seems to be working fine. It looks like all it was, was a cord to something. All it says on it is 16/3 type sjo neoprene I unplugged the plug and the line went dead. I don't think I even want to know how this all came about. But, like I said, the mind got to tickin and looks like the problem is solved. Any ideas now after the explanation what this was? I tested the connections numerous times and always came up with 120, never 240? Thanks, greg

I believed you when you said, "Â I replaced (the original tank), wired it as directed." Now, this new tidbit has me concerned about the whole electrical scheme.

As I started to read your message, I expected that you were trying to say that there was a circuit taken off of one leg of the line. But you describe it as a line coming into the heater and powering one of the elements. That suggests that the other element is also powered by a simplex, 110-V circuit. If so, this needs rewiring as you have a seriously miswired condition.

I suspect this because you said: "I tested the connections numerous times and always came up with 120, never 240" To get 240 V, you need to have two legs of the service wired into the heater. And this would put each (say, the Âblack and the ÂredÂ) on each heater, the upper and the lower.

Since each of them has a second terminal, those are wired to the neutral (white) wire. If that is the case, that you have a 3- or 4-wire cable properly connected to the heater, then it means that the one element was not able to be shut down by the thermostat.

Moreover, it also appears that the chance wiring has allowed the one element to be powered by 240V via the cord connection. Certainly, removing this cord is the right and the first thing to do.

It appears that, for the first six hours, the new heater was being warmed by only one element. When the thermostat attempted to shut down both elements, the miswiring stopped one and started the other at doubled voltage. (Boom!)

While a water heater is power with 240V, the elements operate independently at 120V, each. They should never see 240V, unlike the heating element in a clothes dryer.

Now, if the unit is properly wired, you can test voltage again and get the following results. If the colors are Black, Red and White (and Green, if available,) the voltages will read as follows:

B to R > 240V; B to W > 120V; R to W > 120V; W to G > zero V. For purposes of testing only, you should get the same voltages comparing a HOT wire to either neutral or ground (Green.) The White and Green will only share a terminal in the service entrance panel. (Different, though if the feed is a subpanel.)

Please reply.

Pinoke

That's funny, I wondered about the wiring myself. Also, given the issues I've been experiencing at home, I also wonder if OP has a check valve or pressure regulator in their system, thereby requiring an expansion tank.

Sorry to confuse. Its a 20 gallon, 120 volt, 1500 watt, single element heater. It is hooked up as described/diagrammed in the installation guide. The exception was the extra electric line run from the wall outlet, through the side of the cabinet and wired to the element also. Basically, each post of the element had 2 wires going to it (both the same color just different power sources). Basically the thermostat controlled 1 set and the power outlet the other. The wires from the outlet were always on because they were coming directly from the outlet to the element and not in any way connected to the thermostat. This was causing the element to continually stay on, increase the temperature and pressure thus activating the TP relief valve. I've done away with the "extra" power source and its now wired as directed with no extras. Does that make a little better sense? Sorry for the alarm and confusion my earlier post caused. Seriously though, thank you for your concern for me and my families well being, its nice to know there are people out there who truly care. Take care, Greg

HELP,
Hope it is Ok to ask question here. Put in a lowboy Hopt water heater in a remodel. Had a contract to sell the house until one of those house inspection company from the re company came to inspect for the buyer. He said my water heater did not have the extension on it. DUH? It is a low boy with a T P Valve on the side. Is ot suposed to have an extension?
Thank you Carla

ItÂs "OK," Carla. But the question is not clear. Maybe you should ask the inspector what he meant by "extension" and where it is to be placed. And since that could be your own, different issue, You could start a new thread, using the new description.

Pinoke

Pinoke, Did I clear up my issue and does it sound safe now? Thanks, Greg

I believe carla is referring to a piece(s) of pipe connected to the t&p valve to direct the water downward. Its a simple easy fix.

Greg,
Yes, I think you cleared it all up and found the problem. But, please, donÂt think my opinion counts for anything, IÂm just blogging here. A water heater can be a very dangerous appliance. On the other hand you have had a plumber involved and I would think that is sufficiently due caution.

The one issue that I remain confused with is why did the un-regulated wiring work on the original unit? In fact, why was it there to begin with? The picture is a bit unclear, but I trust that you understand it better than I do.

For some reason, I continue to believe that the original wiring was an attempt to tap power from the heater circuit. Anyhow, with that cord gone, itÂs so straight-forward and simple that itÂs hard to disagree.

Pinoke

As to Carla, she started her own thread for her issue. I just donÂt expect an inspector to call the pipe an Âextension. If I were to guess, I would think the inspector did not see a metal connector on a gas heater, required 18" above the connections. No relationship to the T&P valve.

I think it is peculiar that a person could see the two FIP threads on a T&P and not expect to use them both.

Pinoke