What am I missing?


  #1  
Old 07-30-05, 04:56 PM
89ACC
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What am I missing?

My electric water heater (Kenmore) has stopped working altogether. It's just over a year old. I'm getting ice cold water only. I'm getting 220V to the heater (it was tested and confirmed onsite by the power company), I've changed both thermostats and both elements with the Sears replacement parts. I actually changed the upper thermostat and upper element twice, figuring that maybe I got unlucky and the replacements were bad right out of the box. Neither reset switch ever trippped, nor did the breaker. I made sure the tank was full and all air was out of the pipes prior to turning the power back on, so I know I didn't fry the elements. Ohm meter shows everything is fine, so the heater shoud be working but it's not. My final thought was that maybe the dip tube broke, so it's cycling cold water right back out the hot side, but I opened the drain valve at the bottom and the water that came out was also ice cold (I figured it would be hot or warm if the elements were working but the dip tube was broken). I have no other ideas on what could be wrong. Any thoughts would be appreciated.
 
  #2  
Old 07-30-05, 06:14 PM
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If the dip tube was cracked or broken you would still get warm water on the initial draw down. Here are a few things to recheck.

1. Make sure you test with an ohm meter across both terminal of the element at the same time. To check one side of the element to ground at a time will not show you combined voltage.

2. If possible place an amp meter on one wire lead going to the element. This will show if the element is actually drawing current.

3. Make sure your water is not continuously running thru the heater never getting a chance to heat. Several ways you can test this is to place your ear up to the heater and see if you hear water running. You can also turn off the water inlet valve at the heater to see if the heater heats up.
 
  #3  
Old 07-30-05, 07:44 PM
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#3- Great idea
A few years ago I had a call where the h/o changed the water heater twice. I put a screw driver to the hot water side side and you could hear water running. Next I spotted the water meter and water was flying thru. Make sure no water is being used and go to the water meter and check the hand for movement.
should not move.
 
  #4  
Old 07-31-05, 06:15 AM
89ACC
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Thanks for the advice. I did check across the 2 terminals of both elements with the power on and I'm getting the correct voltage, so power is getting there. With the power off and with the wires disconnected, I'm getting the correct resistance across the element terminals (about 15.4 which I understand is correct for 3800 watt elements). I know that cold water is not running constantly through the heater b/c I'm not on city water (I have a well), so if that was the case, I'd hear the system running on and off as the bladder tank and well pump continue to work, which they're not.

I'll check to see if the elements are drawing current, but I tried two new upper thermostats, since it's my understanding that the upper thermostat controls the lower one. What are the chances I got 2 bad uppers right out of the box? I also tried one new lower thermostat, just in case. This problem is just baffling.
 
  #5  
Old 07-31-05, 12:06 PM
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Something is being missed here that needs reviewing.

If you have a CONSTANT 220v going to your heating element as you measured across both terminal and not to ground then the thermostats at this point are not the problem since you have voltage at your element. Please post the EXACT voltage that you are reading.

If you have resistance when measuring your element and you have voltage then your element must warm the water UNLESS you have the incorrect element for your voltage. Please post the ratings stamped on the side of the elements for us to review.

Since you are on a well and nothing has been discussed about bladder pressure, line storage etc, then it would be easier to just shut off the water supply valve at the heater to eliminate this variable.
 
  #6  
Old 07-31-05, 05:28 PM
89ACC
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The ratings on the sides of each element are 3800W/240V, both are exact replacements for the elements that were in there before.

I just rechecked the voltage across the upper element. Yesterday I remember it being about 251-252, but now it's 0. Resisitance across the element is still about 15.4. I assume this points to a defective upper thermostat since it controls the power to the element.
 
  #7  
Old 07-31-05, 08:00 PM
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The upper thermostat in most domestic applications transfers the voltage to the lower thermostat once satisfied. With a cold water tank the upper element should be the element that has voltage to it. Don't alway assume the thermostat is bad before checking across both terminals at the top of the hi-limit switch.
 
  #8  
Old 08-02-05, 08:42 AM
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Just a thought. Is there a brass jumper connection installed between the high limit section and the thermostat section on the thermostat assembly? On some models, the jumper has to be there.

Nashcat
 
  #9  
Old 08-02-05, 02:59 PM
89ACC
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Yes there is a jumper bar installed.

I rechecked everything today and I am definitely getting power to the heater. There are three hot wires coming to the heater (three phase power I assume), which I disconnected from the wire nuts and separated so I could get three clean readings. Each individual wire read 120-121 volts to ground. I then reconnected them to the heater, measured each thermostat terminal (each screw) to ground and got the same 120-121 at each terminal.

Then I disconnected one of the hot wires from the upper element. Voltage from that disconnected wire to ground was also 120-121. Voltage from the wire I left connected to the element to ground was also 120-121. I take that to mean that voltage is getting to the element. But, voltage across the 2 terminals of the element when both hot leads were connected is 0. Does this mean the element is bad, despite a resitance measurment of 15.3-15.4, or is that normal?

I'm really baffled here. I do appreciate everybody's help greatly and if you guys have any other diagnostics you could recommend, I'll certainly try them out. Thanks again.
 
  #10  
Old 08-02-05, 05:16 PM
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When you had your wires totally disconnected from the water heater and were testing them one by one to ground did you ever test across any two wires? From your description it sounds like your 3 phase circuit is all on the same phase. Is the breaker to turn off the power a single 3 pole breaker?
 
  #11  
Old 08-02-05, 05:40 PM
89ACC
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It is a 3 pole breaker in a seperate subpanel box all by itself. I have had the breaker box cover off and the two outside breakers have the two hot leads on top coming from the meter outside (an offpeak meter, seperate from the main house meter), with the red wire underneath one breaker and black wire underneath the other breaker, going to the hot water heater. The middle breaker has no wire coming into it from the top, but has the white wire underneath leading to the hot water heater.

I haven't tested across the 3 wires. Should I unscrew the wire nuts again, separate the 3 wires and test across the different combo's (white/red; white/black; black/red) and post all three results?

When the heater was first installed, the wire connections were: black/black(heater wire), red/blue(heater wire) and white/yellow(heater wire), and it worked fine up until the point it just stopped alltogether. I changed no wiring in between.
 

Last edited by 89ACC; 08-02-05 at 05:50 PM.
  #12  
Old 08-02-05, 07:56 PM
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If I am reading this correctly you have two 220v single phase ( two hot wires) and a neutral (white) running to your heater. If this is correct you should change your breaker to a two pole reflecting the amperage of the heater and appropriate wire size.

Now we must figure out how your water heater was wired incorporating that strange neutral. This is not a NORMAL installation. There are three scenarios.

First is that the neutral is not being used and you have 220v (red and black leads) supplying power to your elements. If you measure voltage across the top two terminal on the hi-limit( the one with the red button) you should have 220v.

Second is you are using one hot leg and the neutral and you are not using the other hot leg. This would give you 110v if you measure voltage across the top two terminal on the hi-limit.

Third is you have one hot leg and neutral supplying the upper element and the other hot leg and same neutral supplying the second element.

If you have the second or the third case wiring then you put the wrong voltage elements in when you initially changed them.

In your previous post you said you measured 120v across all 3 wires going to ground coming from the breaker panel. How is that possible when the white wire is not connected to the breaker?
 
  #13  
Old 08-04-05, 05:56 PM
89ACC
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Alright, the problem is fixed. I remeasured the voltages on all three wires and I do have 120 volts coming off the white wire, which must be tied into the red wire at the breaker box in some way. Perhaps the two breakers have some sort of jumper? I say that because when I measured across the bare wires, I got the following readings: red/black 238 volts; white/black 238 volts; red/white 0 volts. I assume that means the 120 volts coming off the red and white wires must be on the same phase. So what I did was I capped the white, and rewired the heater in a manner other than the way the electrician wired it after it was installed. He used all three wires, while I rewired it by tying the hot black wire to the black/blue heater wires and the hot red wire to the yellow heater wire. The black heater wire goes directly to the lower element and the yelllow and blue wires go directly to the upper thermostat. That gave me 238 to the upper thermostat and element and 238 to the lower element once the upper thermostat turned on the power to the lower thermostat. I turned up the temp settings on both thermostats (the lower one set higher than the upper one), and now the heater is producing plenty of hot water.

My guess is that the upper thermostat was actually the part that went down when I lost hot water. However, I'm still wondering why the heater was producing hot water before (when the heater was wired incorrectly), and it wouldn't do it after I changed the thermostat, but before I changed the wiring around. Just doesn't make sense.

Thanks for everyone's suggestions and for anyone else reading this post, make sure you have a multitester and know how to use it. It's invaluable for figuring out electrical issues. It sure helped me get to the bottom of this problem.
 
  #14  
Old 08-05-05, 12:08 PM
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It might be working but it isn't wired correctly.

My Kenmore book says for a two wire connection: yellow goes to L1 and blue/black goes to L2. This is what you have now and I would GUESS you are bypassing the off peak feature.

For a 3 wire lead it says L1 to yellow, L2 to blue and L1/L2 to off peak meter. I would GUESS this is the third wire from the box.

It also says, "off peak meter operates bottom element only."

I think I would have this checked even though the way it is wired now should work fine. I know nothing about off peak and such.

Baldwin
 
 

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