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120V Failure - Water Heater


J Goddard
Go to solution Solved by Tom Wallis,

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Over the past several weeks, the Atwood GC10A-4E has not worked on the 120V however works fine on propane. My initial troubleshooting included checking the electrical outlet above and behind the water heater. All good there. Of course, can't access the relay which is mounted on the back of the water heater - just not enough room through an access door in the pass through compartment. So, I drained and removed the water heater. Actually not a horrible job. It didn't take long to discover why it hasn't been working on 120V. See photo. The neutral (white) wire shows signs of arcing and the wire nut was melted into the green ground wire. If you look close, the plastic box shows sign of some melting too. Kinda scary. The Water Heater breaker never did trip; I just turned it off after a couple of times when I couldn't get hot water from 120V and used propane.

My question for the group is do you think it safe to rewire? That would certainly be a straight forward task. Then I would test prior to reinstalling by filling the unit, plug into 120V using extension cord and temporarily wire around the 12V relay. Needless to say it also needs a full flush and vinegar treatment. 

Of course another lingering question is how did this happen? Have any of you seen or heard of this type of failure? 

Oh, I took a resistance reading across the heater element - 12 ohms. Does this sound right?

Thanks...

IMG_0736_1.jpg

Edited by J Goddard
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I would say that a poor connection in the wire nut caused the wires to overheat due to high resistance. And 12 ohms sounds just about right for the element. After replacing any faulty or damaged wire and connections and testing as you suggested I would not be afraid to use it.

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I had the same problem.  Also had the spade connection to the relay overheat and cause the relay to fail.  I replaced the relay.  I could access it by removing a couple drawers, then accessing but only with one hand.  I just learned about WAGO connecters and may replace my wire nuts installed singlehandedly with WAGO.

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@Seward G WAGOs are mint.  Basically all we use now in the elevator industry for control wiring connections.  
There are a few different types, I personally prefer the “lever-nuts” which allow for reuse and ease of entry.  

They other “push-in” style are one time use really and it’s pretty silly trying to get a stranded wire seated properly in them. 

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Just wanted to add that it’s important to use a properly rated WAGO.  there are different sizes for different ampacities.  The WAGO 221 for example is good for 30 amps at 300V and can accept wiring ranging from 20-10 AWG. 

 

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Thanks to those who weighed in on this topic. I didn't know about the WAGO connectors but am going to get some today. Also didn't realize that others had experienced the same failure. Now I am wondering where else Monaco may have used wire nuts for electrical connections. 

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57 minutes ago, J Goddard said:

Thanks to those who weighed in on this topic. I didn't know about the WAGO connectors but am going to get some today. Also didn't realize that others had experienced the same failure. Now I am wondering where else Monaco may have used wire nuts for electrical connections. 

There are many other places where wire nuts are used.  BUT....FWIW.  I would definitely do some research before going down a path that might not be as robust.  If you look at the failure, it was a High Resistance connection.  What I PERSONALLY would do is go back with the Silicone (Dielectric) filled wire nuts that are used on well pumps where the connection is made in a J Box and is outside in all sorts of weather.  These are the SAME type that are supposed to be on irrigation systems.  They come in all sizes.  Odds are you need the Blue ones that are for #12.  I have helped neighbors as well as working with a Professional Geologist that runs a well recovery service and has lectured on pump installs and such.  He uses them....we just finished installing my new pump this morning.  If you look at the contact area of a properly installed wire nut area, you have quite a bit of surface (for good connection) area.

I did do a lot of reading on the WAGO (brand) and the competitors.  They are widely used in the US for LED fixtures and such....but NOT intended for VIBRATION.  They do have a place....but not, IMHO, for use a MH where we have constant vibration.  If you don't want to wire nut, then use a insulated butt splice and a ratcheting crimper.  That is the most contact area and will not, if properly installed, come loose.  Many folks don't like them as they "Failed".  NOPE.....there were TWO main reasons.  Monaco had NO training, to speak of, requirements.  SO, someone quickly went over how to use them and did not emphasize the proper stripped wire length.  The OTHER was that Monaco used the limits (number of connectors) and that was a disaster that happened.

We have wire nuts in J-Boxes and the HVAC and other places.  NOW....one could make a case for max contact from a terminal strip.  BUT, the screws back out.  Think of the high resistance issues we have with ATS and such.

So....I would either use the proper wire nut....which would be well suited for the environment....the Well or Silicone filled ones or use a quality butt splice...

NOT knocking the WAGO concept....except many of us that have been wiring cars for 50 or 60 years were ELATED with the 3M ScotchLok taps or splice....until we realized just how little contact area there was and that was worse in a car.

Hope this helps...

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  • 1 month later...

I need help. During the night we had a heavy thunderstorm. This morning I took a shower and about 1/2 hour later the LP detector went off. Ear splitting to say the least. My son said there was a plastic bag in front of the detector when it went off.

Yesterday I had turned the inside water heater switch on (it lit up red). I’m not familiar with how the propane system works on this RV and the manual didn’t explain it very well. I turned the inside water heater off just in case. We went outside to get fresh air. The switch in the LP bay is switched off. Yet the propane ignited on the water heater while we were outside. 
 

After the alarm I tried to turn the gas off with the manual control valved in the LP bay. The valve didn’t turn clockwise so I turned it counterclockwise. When I turned the knob counterclockwise I heard a hissing so I turned it back all the way clockwise.

I believe the LP alarm went off because of the plastic bag being to close.
 

So my questions are:

How do I turn the propane off;

When the inside water heater switch is on, what does that mean in terms of how the water heater functions?

Does anyone think it is unsafe?

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