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No 110 volt heat in Atwood 10 Gallon Water Heater GC10A-4E


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I've just lost the 110 volt heat in the Attwood 10 gallon GC10A-4E water heater in my 2005 Knight.

I suspect the 110 volt heating element is dead.  The propane side of the water heater works fine.

It seems that the heating element is in the rear of the water heater, which won't make it easy to repair.

Has anyone done this replacement in a Knight or a Diplomat?  Does the water heater need to come out to do the replacement? Or is there some magical access to the rear of the tank when it's in place?  If the water heater needs to come out, then I guess the plumbing needs to be disconnected.  How to get access?

We're using the coach constantly, so I don't want to have the water heater down for long.  Therefore any suggestions about how this is done would be most welcome, so that I can be prepared for the repair.  

Dwight L
05 Knight

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On 6/25/2020 at 12:53 PM, Dwight Lindsey said:

How does one get at the rear of the water heater?

Dwight L
05 Knight

Dwight,

It is almost always necessary to remove the water heater to replace the heating element. It is usually not very difficult. You must drain the water and disconnect the water lines behind the unit. On ours there is an access panel in the bay next to the water heater that allows one to reach in and operate the by-pass valve for winterizing. We are able to use our hand to unscrew the the water line connections thru that access. The 110 VAC power is applied thru a standard wall outlet and you just unplug it. There will also be a 12 volt control line that needs to be unplugged. The water heater can be removed and replaced in a few hours.

Your problem may not be the heating element. First plug a lamp into the duplex outlet behind the water heater to make sure that AC power is present. Next use a meter to make sure that the 12 VDC control signal that energizes the relay that turns on the heating element is working. You should be able to unplug the connector and have someone cycle the switch a the control center to check this. If that is in working order then the relay is another possible point of failure. My experience with RV electric water heaters has shown that the most likely failure is a high resistance connection in the 110 VAC circuit that has overheated due to the large current flow required for the heating element. Sometimes this is a wire nut or relay contact. Often it is not even in the water heater itself and could be in a electrical junction box between the duplex outlet for the water heater and the circuit breaker in the main distribution panel. Don't forget to check that circuit breaker and its connection inside the distribution panel.

The high amperage demand of the water heater will heat these connections and over time they can become so resistive that the heater will not function. Another big point of failure is, if you have one, the power management board located inside the main distribution AC panel. We once lost power to our rear air conditioner because of the power management board. The electric heating element in the water heater is one of the items that the power management system will shed. Examine these connections for signs of overheating. Use a multimeter on the AC range to check both sides of the screw terminals for each shedding relay. There should be AC power on each side. If not then one or more of the relays has failed. I make it a point once a year to go thru and tighten all the screw terminals in the AC distribution panel, the transfer switch, and the power management board. This is very important in an RV because they have a tendency to get loose and cause overheating. The overheating is a snowball thing and the longer it persists the more resistive the connection becomes.

 

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  • 2 years later...

I guess it is okay to add a related question to a very old water heater thread?  My water heater is not working right on 120V.  It works for several weeks, then suddenly it quits.  The breaker doesn't look tripped, but turning it off and back on cures the problem.  It just stopped working again,  this time only a day later.  Instead of flipping the breaker, I decided to do some troubleshooting.  I found a couple of things:  1) the outlet the water heater is plugged into has power, and 2) there is a small area inside the compartment (seen thru the access hatch) that is damp, but not puddling. 

I replaced the thermostat and ECO in Sep/Oct, but still, one of them could be bad... 

I read in this thread that my EMS shedding relay(s) could be the issue,  but I don't know where to find those in my 2008 Knight.

I checked my electrical panel terminal screws in Oct, but maybe another sequence of loosening and tightening of the connections may be worth a shot. 

I'm also opening the access body panel on the passenger side just behind the water heater  to see if there is a junction box there that might have a bad connection.  I wouldn't begin to know where else to look for junction boxes...

Any insights on anything to do with any of this would be greatly appreciated! 

Thanks, 

Steve P

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Steve:

When my 120 volt to the water heater died, I took the water heater out to replace the electric heating element.  I did replace it, sill no joy.  Then and only the I found out that one of the wire nuts connecting the 120 volt cord to the water heater had MELTED and there was no connection.  On mine, there's a little box on the back of the water heater, where the flexible 120 volt cord attaches to the water heater.  Wire nuts inside that box connect the flexible cord to the water heater wiring.

You'll need to remove the water heater from the motor home to get at that box.

Dwight

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Steve, what make/model of water heater do you have.

On my coach the EMS board is mounted in the main service panel breaker box but you have to remove the cover to see the board.  On mine it right of the breaker. 

Do you have a switch that turns the water heater on electric?  My water heater switches are mounted on the kitchen cabinet near the sink below the counter top.  There is one for gas and one for electric.  On my coach the electric switch is actually 12 volt and it controls a relay that turns the 120 volt circuit on.  The relay is mounted in a 6"X6" Ormon box mounted behind my main service panel.  Hard to see and harder to get to.  I was having another problem and saw the box so decided to check it out.  It actually has 2 relays, one for the water heater and one for the block heater.  The relay for the water heater was connected using wire spad connectors and they had been hot so I replace.  I checked then again ~2 years ago and they looked like they had gotten hot again so I replaced them again.   I have this in the back of my mind as a potential failure for the water heater. 

My water heater, a suburban,  has a separate control module that is mounted behind it mounted on the bay wall across from my transfer switch.  Two years ago I was having trouble with the water heater working on gas, it wouldn't ignite.  Pulled the module to take a look and when I pulled it out a couple drops of water came out of it.  Took a hair dryer and dried it out and that fixed the problem.  No idea where the water came from as the rig had been parked in my garage for +1 year.

 

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If you are on 50 amp the load shedding is not functioning, however the power does still pass through a load shedding relay on the EMS board which is inside the AC breaker panel.

You stated that there is 110 volts at the outlet behind/near the water heater so it is not load shedding. 

I have not looked at the schematic for your water heater yet so doing this from memory. There may be a box on the back of the water heater with a relay inside. 

In any case, a voltmeter across the element is in order. Could be an intermittent element but not likely. As suggested, bad connections or a bad control relay. 

 

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I'm still not entirely sure what to do next...  since the water heater clearly has power, it seems it isn't an issue with the wiring or the breaker tripping as a result. So I'm wondering if the new thermostat or the new ECO has an issue.  Could the dampness I noted in the water heater bay have been due to overheating and the pressure relief valve blowing and releasing some water?  (That still wouldn't explain why heating wouldn't resume when the tank cooled down, right?).  I can't quite decide whether to chase that possibility, or some electrical gremlin in one of the relays, or connections.  No clue...

If I chase the connections or the heating element itself, either way, I'll have to pull the whole water heater out of its bay, which seems like a real pain (electrical, water, and gas disconnects, and a tight fit with the styrofoam insulation) .  At least that will allow several assessments.  Does that seem like the next step or have I skipped something?

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