Confusing but simple tech problems

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regval

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The most common Refer heating element is a 325 Watt element for 120VAC. The resistance should be about 44 ohms across the leads from the heating element and zero ohms from either lead to ground.
It's important not only to check the resistance of the element by measuring between each lead (unattached from the control board) but also to check each lead to the outside metal case of the heating element to insure there is no connection (meg ohms or infinite resistance).
 
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DonTom

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The most common Refer heating element is a 325 Watt element for 120VAC. The resistance should be about 44 ohms across the leads from the heating element and zero ohms from either lead to ground.
It's important not only to check the resistance of the element by measuring between each lead (unattached from the control board) but also to check each lead to the outside metal case of the heating element to insure there is no connection (meg ohms or infinite resistance).
Thanks for that info! Those are the type of numbers I would expect. Far from what I am seeing. But obviously you must mean infinite resistance to ground as zero ohms is a dead short.

Also obvious is that my ground fault was more serious than I thought. The heater element must have shorted to ground after it broke. Now I can believe the problem was a short on the AC line as the generator probably saw it as close to being a dead short, but I would expect a low voltage alarm before a missing 1 second of AC after 14 seconds. But it had to be well above a normal load. I wonder if a code 27 can set from an overload.

I just checked the service manual. The very FIRST thing it says to check for a code 27 is the AC voltage. But IIRC, I did and it looked normal during the time I had the issue.

Perhaps when I plug in to the house with no GFI that blew the element apart enough to get rid of the excessive load or short to the generator.

This is all speculation, of course, but an overload shutting down the generator I can make SOME sense out of.

I wonder if I should start a new thread. I have no idea where to start to replace the AC element in my refrigerator. But I think I do have some tech info on my refrigerator that I will read first, just in case there is a clue how to replace the element.

I am now going to consider the big mystery as solved, after finding such a big issue right on the AC line. It sure explains the ground fault issue, it had nothing to do with the rain.

BTW, all this would have been obvious if the refrigerator's outlet had GFI. I will plug in one of those GFI thingies into that outlet after I repair the refrigerator and plug the genny into it.

-Don- Auburn, CA
 

regval

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Don, you’re right, my mistake, don’t know why I said zero ohms to ground. Getting old, I’ll blame in on that!
The ac element usually just sits in the boiler chimney. It may have a screw holding it in place, but it just lifts out of its holder. Sometimes you have to wiggle it some to free it up while lifting, kinda shaped like the letter L.
Good luck
 

DonTom

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Good luck
Thanks, I just now removed it (yeah, at night). But it was a thousand times tougher than shown in the video. I didn't think I was going to be able to get it to move it at all. No trace of play in it at first, after blasting it with a lot of Blaster penetrating oil and waiting. My using a lot of force (and I do mean a lot) and with the help of vice grips, I was able to get some play in it. But even after all that, it would not move up at all. I just stayed with it for about an hour, wiggling as much as possible as I added more oil as I go. Finally got it out, but I destroyed it on the way out. Not that I care, but that is how much force I had to use. I had to use vice grips and other tools to even get any movement at all.

I would like to add one thing to the video that makes it a little easier and can clearly then see what is being done. The bottom part of the outer thingy with that heat sensor (or whatever it is) can be bent out of the way and then we can clearly see the tube the heater element goes down into.

Anyway, thanks again. I didn't intend to remove it tonight until I saw your video. That made it look so easy. But my case was really a lot of work.

I assume the new one won't be as difficult to go in at this one was to get out!

I am not surprised mine was so much trouble to remove knowing it had a short to ground.

-Don- Auburn, CA
 

DonTom

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Don, you’re right, my mistake, don’t know why I said zero ohms to ground. Getting old, I’ll blame in on that!
Not a big deal, I knew what you meant and your info. was very helpful to me and saved me some time.

I wish the edit would not time out in this forum software. A couple of messages back I said I was going to plug the genny into the GFI when I meant refrigerator.

I am also getting old, so I will use your excuse as well.:)

-Don- Auburn, CA
 

DonTom

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Don, no that outlet for my converter is not a GFI outlet. At least there's no buttons on it.
It seems strange that the area that is perhaps the most likely to get a ground fault is the only outlet in my RV that doesn't use GFI. But I guess GFI is mainly to save people and they don't expect that outlet to be used in any other way.

Or perhaps it switching back and fourth causes too many GFI trips.

I have an GFI adapter that plugs into a non-GFI outlet that I will plug into that outlet. I will know to check it once in a while as a ground fault will simply make it switch to gas and I wouldn't even know it tripped. It would be nice if they would put led indicators on the front of the refrigerator so I would know which source I was using. There is no way to tell on mine, just an "auto" and "check" light with no changes from AC / propane when working normally.

Perhaps that is why they don't use GFI. If it trips, most people won't even know as the refrigerator will simply continue working but on propane.

If it trips too often, I will remove it. The more I think about it, I bet that is the real reason they don't use GFI there, switching from propane to AC probably trips GFI too often. I will soon know, as I am going to try it and let it switch back and fourth several times between AC and propane.

-Don- Auburn, CA
 

DonTom

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I assume the new one won't be as difficult to go in at this one was to get out!
Boy, was I wrong there. I tried to put the new one in today, it gets stuck around 25% in. And that is with penetrating oil on it.

But the old one now goes in and out easily. I only have trouble with the new one. I finally gave up trying to force it in, before I break it. I took it back out. I am now trying to loosen it up a bit more by using the old one, forcing it in and out and twisting it as I go up and down with it many times.

There seems to be rust in the tube the heat element goes into. Perhaps that is causing the problem with the new one. I couldn't find a micrometer here to measure the difference between the old and new heater element, but I will have one in a few days (Amazon) and also some long round brushes. But both elements look the same by eye.

Is there another better way to deal with this, where then new heater element is too tight?

And is it the norm for them to be a bit thicker when new?

-Don- Auburn, CA
 

Old_Crow

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How about a gun cleaning rod and a brass bore brush to clean out the tube? Then blow it out with air.
 

DonTom

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How about a gun cleaning rod and a brass bore brush to clean out the tube? Then blow it out with air.
That sounds like a great idea! I just ordered a pistol cleaning kit on Amazon. I could use one here anyway, as all my gun cleaning rods are in Reno.

The rod has to be somewhat short to fit in there. I will try this kit first. 10.5" inch rod, two in series, plus brush length should be about right.

I will post back here what caliber the tube is. :)

-Don- Auburn, CA
 

DonTom

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I will probably receive my pistol brushes tomorrow. But today, I received my new digital caliper.

The old refrigerator heater element , measured at at the thickest area I could find that goes into the tube, is 9.70mm. The new heater element measures 10.07mm. The difference between these two measurements is 0.37 mm and that is enough difference that the old one fits easily and the new one gets stuck around a third of the way down the tube.

If the brushes do not do the trick, I will try some fine sandpaper on the new heater element.

-Don- Auburn, CA
 

John From Detroit

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Your mention of pistol brushes....

Had a Dodge van many moons ago where the blanged accelerator linkage liked to bind when it went through the firewall via a bushing.... Pistol cleaning kit was how I fixed it.. Mighty useful tool... What did I not clean with it? Pistols. don't have any.
 

DonTom

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Your mention of pistol brushes....

Had a Dodge van many moons ago where the blanged accelerator linkage liked to bind when it went through the firewall via a bushing.... Pistol cleaning kit was how I fixed it.. Mighty useful tool... What did I not clean with it? Pistols. don't have any.
Well, I do have pistols here, but I also doubt if I will ever use my pistol kit here for pistols. All the pistols are still NIB--never fired. And will most likely stay that way.

I don't know why I never thought of that idea to use a pistol cleaning kit. Appears to be the perfect tool for such things as cleaning tubes for heating elements! I should receive it today and then I will try to complete the repair of my refrigerator.

-Don- Auburn, CA
 

DonTom

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A piece of wood dowel wrapped in sandpaper is another simple and handy tool for cleaning tubes.
Gary,

I would be afraid some of the sandpaper would get caught in there. I don't think there is way to get to the bottom of the tube. Or is there? Or is it possible to remove the tube if I cannot clean it out while in the RV?

I don't have any wood dowels here. But if the gun brushes do not work, I will try various other things, which can include a trip to Home Depot to get some wooden dowels.

I figure at worse case, I just run my refrigerator on propane even when I have AC available. It's a lot more important to me that it works on propane, which it does. I figure running the refrigerator on propane at all times won't use up that much anyway. But I prefer to fix it right, of course.

Have you heard of this problem before, where to old one would fit fine but the new one would not?

I find it surprising with all the force I had to use to get the old one out. But after I did, it slides back in and out easily. But the new one gets stuck at just a few inches down the tube.

I should get my pistol cleaning kit late this afternoon.

-Don- Auburn, CA
 

Gary RV_Wizard

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I've not heard of the dimension difference you found in the old/new elements, but it's fairly common to have problems fitting it into the tube. Rust, of course, and maybe heat-induced warping. The heater tube is typically welded to the boiler. Is the replacement an OEM part? Even so, the manufacturing tolerances are probably large enough to account for the difference.

As for the dowel, I always use a long enough dowel & sleeve of sandpaper so that I can easily keep a hold of the end. And if I'm serious, I glue the paper on or use an adhesive-backed paper. Understand you probably don't have much working room on this chore, though.
 

DonTom

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Okay, we all need to remember this:

DO NOT USE GUN BRUSHES!

Here is the problem:

They go in very easily. They do NOT come back out. They are designed ONLY for the direction of a bullet.

And when I say they don't come out, I mean they don't! Period!

I broke my new gun rod for the brush inside the tube when I tried to force it back out. So my refrigerator will never work on AC again. I doubt it is possible to remove or even to fix for AC at this point. If that tube were open at the bottom, that could have been the fix.

Too bad we could not put the gun brushes in the opposite way. Hard in, easy out. That would be the perfect tool to clean a refrigerator tube.

The good news is, this is not that big of a deal to m
e. I will just only use propane from now on, even if at a full hookup RV park.

-Don- Auburn, CA
 

Mark_K5LXP

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Might be too late if there's only a nub of the cleaning rod in there but if you were to use a section of the rod that didn't swivel and threaded the brush onto that, then you could rotate the rod and brush at the end, which will allow the bristles to move and change orientation so you could pull it out. I've used rifle, pistol and shotgun brushes on all manner of engine exhaust and breather ports, and as long as you can rotate the brush via the rod they don't become "one way".

Mark B.
Albuquerque, NM
 
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