Water Heater Fried Wiring

[dbsea]

Anyone know what would cause the wiring on my iso temp 40L water heater to end up fried like this? The spade terminal on one side is completely fused/melted. See photo link below. Has anyone else seen this happen, and how hard is it to drain it and change the element while it’s horizontal under the fridge?

https://share.icloud.com/photos/01fo_fg ... Cc2Ge-ap_Q

 

[marksandyham]

I see some corrosion which I am sure contributed to a poor connection. A poor connection causes overheating and you see the results. May be able to clean up the connection to the element and replace the spade connector. Try to find a high temperature spade from a local appliance parts store to replace the existing one. Won't stop corrosion but will handle heat better.

 

[dbsea]

Thanks Mark. The element has male spade connectors on it. one is ok, the other is completely melted down / fused / corroded. I ordered a replacement element just to be safe, only $65 from fisheries supply. I have to replace the small wire run and spade connectors all around where there is any corrosion, for sure. I will use Ancor insulated disconnects. My bigger concern is how to ensure the tank is drained before I attempt to remove it. I turned the water pump off and opened all hot/cold water spigots, but there's probably some residual in the tank. I guess the overflow valve, and I'll have to use a bunch of rags or something to collect the water...

 

[SJI Sailor]

It is not difficult to change except for one thing. Drain it using the overflow valve. Remove the wires etc, and then the door. (Isotemp has a PDF online of you search for it, if I recall correctly). Then replace the element in the door.

The difficult part is putting it back together -- in particular, holding the door in place with one hand, aligning it with another hand so the element and seal are positioned correctly, and -- you guessed it -- using another hand to tighten the nuts. Because I only have two hands it took many tries to get everything aligned and held snugly, mostly trial and error. (I could not figure out any good way to use anyone else or any tool to help but I assume there is some clever trick.)

BTW you might go ahead and replace both the large and small gaskets (door + element) at the same time, since that is cheap and would require almost zero additional effort.

 

[dbsea]

It is not difficult to change except for one thing. Drain it using the overflow valve. Remove the wires etc, and then the door. (Isotemp has a PDF online of you search for it, if I recall correctly). Then replace the element in the door.

The difficult part is putting it back together -- in particular, holding the door in place with one hand, aligning it with another hand so the element and seal are positioned correctly, and -- you guessed it -- using another hand to tighten the nuts. Because I only have two hands it took many tries to get everything aligned and held snugly, mostly trial and error. (I could not figure out any good way to use anyone else or any tool to help but I assume there is some clever trick.)

BTW you might go ahead and replace both the large and small gaskets (door + element) at the same time, since that is cheap and would require almost zero additional effort.

Thanks, and yes, the replacement kit for the element comes with both sets of gaskets so I definitely will replace those. How do you drain the overflow without (further) soaking the plywood underneath? As you well know, there's not a lot of room down there. Appreciate the mutual suffering on getting it back together, at least I'll know I'm not alone! 😀

 

[S. Todd]

I have had good luck draining the hot water tank on our R29S by putting the disconnected water line from the fresh water pump in the hose to my shop vac with the hot water faucet open at the galley sink to allow water back in. The shop vac does all the work. Or you could just suck it up with the shop vac at the tank drain but in the 29 that is lots harder to get to.

 

[SJI Sailor]

For the overflow drain, I've mounted a small container there to catch water as it occasionally comes out due to pressure relief.

When draining the whole tank, I use a small 12v "stick" pump to transfer the water as it comes out into that container to go to a bucket. OTOH if you're otherwise happy with the drain then I think a one time drain over the painted plywood is tolerable.

 

[dbsea]

For the overflow drain, I've mounted a small container there to catch water as it occasionally comes out due to pressure relief.

When draining the whole tank, I use a small 12v "stick" pump to transfer the water as it comes out into that container to go to a bucket. OTOH if you're otherwise happy with the drain then I think a one time drain over the painted plywood is tolerable.

good ideas all around. I'll see what I can figure out. do you know what size the fitting is on the overflow valve? is it 1/2" NPT?

 

[SJI Sailor]

I don't recall on the fitting, unfortunately.

FWIW, I had the idea to attach a hose to it to drain down to the bilge ... but didn't have room even to attach an elbow fitting without removing or cutting something, so I gave up on that plan and have not yet circled back to it. Probably depends on the orientation of the valve installation.

 

[dbsea]

I don't recall on the fitting, unfortunately.

FWIW, I had the idea to attach a hose to it to drain down to the bilge ... but didn't have room even to attach an elbow fitting without removing or cutting something, so I gave up on that plan and have not yet circled back to it. Probably depends on the orientation of the valve installation.

no worries, thank you. On the elbow fitting / drain option, which direction would the hose go to drain into the bilge? I can't really tell with the limited visibility in there. Wondering if I should yank the fridge to do all of this...

 

[SJI Sailor]

I'm away from our boat but if I recall correctly, the outlet on the pressure relief valve on ours points straight down with less than an inch of clearance from the plywood. That's why I could not get an elbow in place to divert it sideways instead.

My plan had been to attach an elbow, attach a short hose, and then reduce the line to 3/8 (or something) and run that around by the water tank and into the bilge. Since I could not easily attach an elbow or anything else, I just mounted a small catching container there instead (and that has worked great).

Other options might be some kind of flexible rubber attachment, cutting the plywood to get room, or reseating the pressure valve to point somewhere different (perhaps the best option). I postponed those decisions once I had a good enough solution 🙂 and a nice thing about the container is that I can see exactly what is happening with the overflow.

As for removing the fridge, that would probably help with accessing the front panel/door on the water heater to replace it. And make it easier to research the pressure valve if you went that route. Didn't seem required to me but OTOH not a bad thing to do in general just to see what's going on, I guess. HTH!