Water heater element

D

Deb

New member
Oct 23, 2016
358
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Back again :) Last summer I fried the water heater when we ran out of water and the heater was left on (noob error!). There is a small aluminum
plate bolted to the front of the tank (green wire (ground) attached to it) with what look like the high limit switches on my furnace at home - don't
know what it is but I'll bet that it is something along those lines. Obviously generated a lot of heat - element trying to heat and empty tank.

I can't find anything about this in the binders of upgrades from my PO, but I do see that Jim K lists the same heater.

Anyone know exactly what that little panel is & does? And before I go and pull the element, what to test and what to be looking for on my meter.
Perhaps the element was saved by the "whatever" and that is what needs replacing. Posted pictures...

http://www.gmcmhphotos.com/photos/data/7214/medium/IMG_2495.jpg
--
Deb McWade
Logan Lake, BC, CAN
"Li'l Sister"
'77 Kingsley, 403, EBL EFI;
TZE167V101404
It's Bigger on the Inside!
 
Are you talking about the thermostat? Send me a picture and I’ll tell you.

Emery Stora

>
> Back again :) Last summer I fried the water heater when we ran out of water and the heater was left on (noob error!). There is a small aluminum
> plate bolted to the front of the tank (green wire (ground) attached to it) with what look like the high limit switches on my furnace at home - don't
> know what it is but I'll bet that it is something along those lines. Obviously generated a lot of heat - element trying to heat and empty tank.
>
> I can't find anything about this in the binders of upgrades from my PO, but I do see that Jim K lists the same heater.
>
> Anyone know exactly what that little panel is & does? And before I go and pull the element, what to test and what to be looking for on my meter.
> Perhaps the element was saved by the "whatever" and that is what needs replacing. Posted pictures...
>
> http://www.gmcmhphotos.com/photos/data/7214/medium/IMG_2495.jpg
> --
> Deb McWade
> Logan Lake, BC, CAN
> "Li'l Sister"
> '77 Kingsley, 403, EBL EFI;
> TZE167V101404
> It's Bigger on the Inside!
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
> Are you talking about the thermostat? Send me a picture and I'll tell you.
>
> Emery Stora

Hi Emory. It's the first picture there in the post. I can't see it being a thermostat - it doesn't contact the inside of the tank at all so would
have no way of registering water temp. It's just attached there onto the front of the tank with a couple of nuts and washers where the ground wire
attaches. (second photo)

Maybe it doesn't come through on your end. I'll PM you with a couple of pictures. Deb
--
Deb McWade
Logan Lake, BC, CAN
"Li'l Sister"
'77 Kingsley, 403, EBL EFI;
TZE167V101404
It's Bigger on the Inside!
 
> Are you talking about the thermostat? Send me a picture and I'll tell you.
>
> Emery Stora
>

> >
> > Back again :) Last summer I fried the water heater when we ran out of water and the heater was left on (noob error!). There is a small
> > aluminum
> > plate bolted to the front of the tank (green wire (ground) attached to it) with what look like the high limit switches on my furnace at home
> > - don't
> > know what it is but I'll bet that it is something along those lines. Obviously generated a lot of heat - element trying to heat and empty
> > tank.
> >
> > I can't find anything about this in the binders of upgrades from my PO, but I do see that Jim K lists the same heater.
> >
> > Anyone know exactly what that little panel is & does? And before I go and pull the element, what to test and what to be looking for on my
> > meter.
> > Perhaps the element was saved by the "whatever" and that is what needs replacing. Posted pictures...
> >
> > http://www.gmcmhphotos.com/photos/data/7214/medium/IMG_2495.jpg
> > --
> > Deb McWade
> > Logan Lake, BC, CAN
> > "Li'l Sister"
> > '77 Kingsley, 403, EBL EFI;
> > TZE167V101404
> > It's Bigger on the Inside!
> >
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

Actually, Emory, I think you are right! I google imaged some RV heater thermostats and this one from Suburban looks basically identical.
https://pdxrvwholesale.com/products/suburban-water-heater-120v-thermostat-limit-switch-130-232306
So... I wonder if the thermostat frying may have saved the element, or did I fry both :)

--
Deb McWade
Logan Lake, BC, CAN
"Li'l Sister"
'77 Kingsley, 403, EBL EFI;
TZE167V101404
It's Bigger on the Inside!
 
If you send it to the gmclist (as you have) I don’t see the pictures. You’d have to send it to emerystora

Emery Stora

>

>> Are you talking about the thermostat? Send me a picture and I'll tell you.
>>
>> Emery Stora
>
> Hi Emory. It's the first picture there in the post. I can't see it being a thermostat - it doesn't contact the inside of the tank at all so would
> have no way of registering water temp. It's just attached there onto the front of the tank with a couple of nuts and washers where the ground wire
> attaches. (second photo)
>
> Maybe it doesn't come through on your end. I'll PM you with a couple of pictures. Deb
> --
> Deb McWade
> Logan Lake, BC, CAN
> "Li'l Sister"
> '77 Kingsley, 403, EBL EFI;
> TZE167V101404
> It's Bigger on the Inside!
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
Deb,
It appears to me to be two fixed temperature thermostats mounted on the front of the tank. The physical mounting onto the tank conducts the heat to
the thermostats.

They are wired in series so i'm guessing one sets the normal shut-off temperature of say 120F. The second one will be a backup in case the first one
fails maybe set to 140-150F. Most will have an adjustable thermostat.

Be careful working near that thing, the 120V connections are exposed at the heater element.

Your element is likely fried because it would over-heat before the thermal conduction could trip the thermostats. A trick to help prevent this is to
install a wind-up timer in place of the water-heater switch. Simply crank it up to 45 minutes or so just before you need hot water. My heater can
give me hot water in about 15-20 minutes. The timer then shuts off the power after the set period saving you from remembering to shut it off. You
soon remember to turn on the timer after 1 or 2 cold showers.

BTW, you can replace the heater element with a more robust 240 Volt 4Kw element. When operated at 120 volts, it will consume only 1Kw.

--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
 
I would expect that you burnt out the heating element. You can easily test the thermostat. They should pass current until they get hot and open the circuit. A VOM set on resistance (ohms)or a test light should allow you to test them.

Emery Stora

>

>> Are you talking about the thermostat? Send me a picture and I'll tell you.
>>
>> Emery Stora
>>

>>>
>>> Back again :) Last summer I fried the water heater when we ran out of water and the heater was left on (noob error!). There is a small
>>> aluminum
>>> plate bolted to the front of the tank (green wire (ground) attached to it) with what look like the high limit switches on my furnace at home
>>> - don't
>>> know what it is but I'll bet that it is something along those lines. Obviously generated a lot of heat - element trying to heat and empty
>>> tank.
>>>
>>> I can't find anything about this in the binders of upgrades from my PO, but I do see that Jim K lists the same heater.
>>>
>>> Anyone know exactly what that little panel is & does? And before I go and pull the element, what to test and what to be looking for on my
>>> meter.
>>> Perhaps the element was saved by the "whatever" and that is what needs replacing. Posted pictures...
>>>
>>> http://www.gmcmhphotos.com/photos/data/7214/medium/IMG_2495.jpg
>>> --
>>> Deb McWade
>>> Logan Lake, BC, CAN
>>> "Li'l Sister"
>>> '77 Kingsley, 403, EBL EFI;
>>> TZE167V101404
>>> It's Bigger on the Inside!
>>>
>>>
>>> _______________________________________________
>>> GMCnet mailing list
>>> Unsubscribe or Change List Options:
>>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>
>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
> Actually, Emory, I think you are right! I google imaged some RV heater thermostats and this one from Suburban looks basically identical.
> https://pdxrvwholesale.com/products/suburban-water-heater-120v-thermostat-limit-switch-130-232306
> So... I wonder if the thermostat frying may have saved the element, or did I fry both :)
>
> --
> Deb McWade
> Logan Lake, BC, CAN
> "Li'l Sister"
> '77 Kingsley, 403, EBL EFI;
> TZE167V101404
> It's Bigger on the Inside!
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
It appears your heating element shorted out as it failed and melted the wires and damaged the 2 klixon thermostats . You will need to replace the
heating element and the 2 klixon thermostats also the damaged wires. The good news all these parts are cheep.
--
Roy Keen
Minden,NV
76 X Glenbrook
 
Well those thermostats are definitely done - crispy! I checked the element itself and got 7.2 ohms resistance! Hard to believe, but it should be
more I think. Not certain what W/V is in there right now. Couldn't get my head twisted around upside down to read the specs on it. But either way,
I'm going to get a new element and 2 new thermostats. Bruce I think you're right about one being higher temp. One is 32-6 marking and the other is a
62-6. Now not sure which is which, but the Suburban one is a 120 and it's 62-6 on both units.

So thermostats, a 4000W/240V element and a timer switch!! My job for the week. I'll pull the old one first before I order a new element.
Tomorrow.....

Thanks all!
--
Deb McWade
Logan Lake, BC, CAN
"Li'l Sister"
'77 Kingsley, 403, EBL EFI;
TZE167V101404
It's Bigger on the Inside!
 
Actually the two should be the same temperature setting. The reason for two in series is because if there were only one and it failed in a closed position it could cause the heater to overheat to the point of exploding.
With two in series if one fails in the closed position they the other should still open the circuit when the temperature is reached. One should inspect your system periodically to be sure to catch the fact that one has failed.

Emery Stora
77 Kingsley
Frederick, CO

>
> Deb,
> It appears to me to be two fixed temperature thermostats mounted on the front of the tank. The physical mounting onto the tank conducts the heat to
> the thermostats.
>
> They are wired in series so i'm guessing one sets the normal shut-off temperature of say 120F. The second one will be a backup in case the first one
> fails maybe set to 140-150F. Most will have an adjustable thermostat.
>
> Be careful working near that thing, the 120V connections are exposed at the heater element.
>
> Your element is likely fried because it would over-heat before the thermal conduction could trip the thermostats. A trick to help prevent this is to
> install a wind-up timer in place of the water-heater switch. Simply crank it up to 45 minutes or so just before you need hot water. My heater can
> give me hot water in about 15-20 minutes. The timer then shuts off the power after the set period saving you from remembering to shut it off. You
> soon remember to turn on the timer after 1 or 2 cold showers.
>
> BTW, you can replace the heater element with a more robust 240 Volt 4Kw element. When operated at 120 volts, it will consume only 1Kw.
>
> --
> Bruce Hislop
> ON Canada
> 77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
> http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
> My Staff says I never listen to them, or something like that
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
If you have 7.2 ohms resistance that's exactly right for a 2,000 watt
120 volt element - so the element may not be toast just yet.

One other element failure mode is leakage to ground - measure either
heater connection to ground and you should see infinite resistance or
very close to it.

Measuring 7.2 ohms across the element and no leakage to ground the
element is probably fine and something else caused your thermostats to
release their magic smoke.

Regarding the 4Kw 240 volt element, keep in mind that will be 1,000
watts at 120 volts or 3140 BTU/hour of water heating. In other words,
much slower (2x) recovery time.

Stu Rasmussen W7QJ
Silverton, Oregon
'74 gutted Eleganza

> Well those thermostats are definitely done - crispy! I checked the element itself and got 7.2 ohms resistance! Hard to believe, but it should be
> more I think. Not certain what W/V is in there right now. Couldn't get my head twisted around upside down to read the specs on it. But either way,
> I'm going to get a new element and 2 new thermostats. Bruce I think you're right about one being higher temp. One is 32-6 marking and the other is a
> 62-6. Now not sure which is which, but the Suburban one is a 120 and it's 62-6 on both units.
>
> So thermostats, a 4000W/240V element and a timer switch!! My job for the week. I'll pull the old one first before I order a new element.
> Tomorrow.....
>
> Thanks all!
>
 
Home Depot will definitely have the element and should have the thermostat. 1000 watts is a good consumption rate. I think that is what the OEM one
was. If you are ever plugged into a 120 volt 15 amp shore power feed, a 2000 watt element will trip the breaker and you will have no power for hot
water or anything else 120 volt at all. When people plug in at my hangar that is what they get - 120 volts at 15 amps.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
 
7.2ohms equals 2kw, but that reading is the cold element resistance. I'm thinking the heater element has a positive temperature co-efficient and the
resistance will increase when hot. Maybe its a 1.5Kw?

Like Ken pointed out, I don't think you want a 2Kw as you won't be able to have hot water on a 15Amp service.

Our 4Kw 240V running 1kw at 120V works well for us. Its surprising how fast it can deliver hot water in the morning!

If you ever have the GFI tripping on shore power, its mostly likely the water heater element shorted or leaky internally to ground (the element's
casing). Even with the breaker shut off to the water heater, it can still trip the GFI because the neutral can leak current to ground. Just something
to remember in the future.

--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
 
The trailer parts place in Gainesville had a selection of elements, I got a 1200 Watt one for the last coach. All my coaches have engine heat for the
hot water. If I arrive after dark, in the morning there's still enough hot water to cook.

--johnny
--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
"I forgive them all, save those who hurt the dogs. They must answer to me in hell" - ol Andy, paraphrased
 
> Home Depot will definitely have the element and should have the thermostat. 1000 watts is a good consumption rate. I think that is what the OEM
> one was. If you are ever plugged into a 120 volt 15 amp shore power feed, a 2000 watt element will trip the breaker and you will have no power for
> hot water or anything else 120 volt at all. When people plug in at my hangar that is what they get - 120 volts at 15 amps.

Haven't got out with the camera to get a shot of what's in there yet (print is upside down and backwards, and I'm not that limber anymore!), but if
it's a 2000W, then I guess the reason I didn't trip your breaker last summer was because I had already fried everything in N. Dakota! :blush: :lol:

Now, I would think that if it's fried, it's fried. Either working or not - like a light bulb? I tested and got nothing when I checked for a short
(connected post to housing) and a consistent 7.0 - 7.2 from post to post. Can I get "half" the resistance I should expect from a 1000W element? I
don't think so, but I defer to those who understand this without having to google everything, like I do :( Either way, I think I will replace with a
4K/240 element to get the original amperage but a more robust build.

I did note that when I disconnected everything (with little bits of crispy black insulation falling off!) one of the connectors (the little fork
connector to the element) was only under by one fork. So it didn't have good contact there. May have been enough when everything was hunky dory, but
when the tank ran dry it was too much. Honestly, not one of the things I had looked at before, so I don't know what kind of shape everything was in
when we took off.
Add to the list of things to check before take-off!
--
Deb McWade
Logan Lake, BC, CAN
"Li'l Sister"
'77 Kingsley, 403, EBL EFI;
TZE167V101404
It's Bigger on the Inside!
 
Found the correct thermostat and it's on order. Thanks to Tom for his help on this too.
You folks have walked me through another one and given me a bit more education!
Gotta love the GMC community. 👍
--
Deb McWade
Logan Lake, BC, CAN
"Li'l Sister"
'77 Kingsley, 403, EBL EFI;
TZE167V101404
It's Bigger on the Inside!
 
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