Testing heating element- Dometic/173712

[PA BAMBI II]

Hello,

My 1964 fridge has been tested and operated safely (out of the trailer) on LP. The fridge does not work on 120 electric. I dug into it today and found the electric heating element. It is a Dometic 135W 110V #173712 heating element.

How can I test it to see if it gets hot? Just plug the fridge in and feel the progress or lack thereof?

I found a replacement online for about $45. Not afraid to spend that on the old girl, but want to be sure it is needed.

Thanks for any input...

[Gearheart]

Test it first with a circuit tester to see if power will go through the element. If not then you know it is toast. Putting the power to it and seeing: if it gets warm, how warm and how fast, would be my second test. It should get hot like a light bulb.

[lewster]

Two ways. Continuity will tell you if the element is in tact but really says nothing about its condition.

Take an Ohm reading with a multi meter. IIRC, you should see 350-450 Ohms as a good reading.


Lew Farber
RVIA/RVDA Nationally Certified Master Tech
Master Tech Energy Systems, Inc.
AM Solar Certified Installation Center
Lifeline Batteries**Magnum Inverters
541-490-6357

[TG Twinkie]

If you suspect it is the original or not much newer. Part with the $45 and replace it.
They have a finite life. Kind of like a light bulb.


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[Jacob D]

Our '67 heating element went out a couple of years ago and it turned out to be a standard Calrod heater available off the shelf from almost any industrial electrical supplier. Your volt/ohmmeter will show an open circuit when tested across the leads if it is burned out. Test any new heater as recommended by lewster and if ok, install it and plug it in. Calrods are very reliable and rugged and the older reefers are simple with no electronics to play tricks on you. I don't recommend plugging a Calrod in before installation. That is a good way to burn yourself and shouldn't be necessary if tested ok.

[PA BAMBI II]

Thanks again for all of your replies. The heating element tests fine and gets plenty hot on direct 110 volt. The on/off switch (gas/electric) works fine. So...

I am thinking it is the thermostat. I am not sure how to test that part or where to source a new one.

Any ideas? I have been having fun troubleshooting today. I think I am close to the answer.

Ben

[TG Twinkie]

You may have a bad connection where the power wires and heating element plug in to the thermostat with spade connectors.
You might try disconnecting the wires at the terminals and reconnecting them. Make sure the power is off.


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[lewster]

Originally Posted by PA BAMBI II

Thanks again for all of your replies. The heating element tests fine and gets plenty hot on direct 110 volt. The on/off switch (gas/electric) works fine. So...

I am thinking it is the thermostat. I am not sure how to test that part or where to source a new one.

Any ideas? I have been having fun troubleshooting today. I think I am close to the answer.

Ben

If you're talking about the 'thermister', which is the little device clipped on to the right most fin in the fridge section, there is a definitive test to determine if it is operating properly.

It involves removing the t/mister from the unit and taking an ohm reading at room temperature. You them soak it in a glass of ice water for about 10 minutes and take another reading.

Dometic has tables listing the required values that you should see for t/misters from the various fridge models.

The other way is to disconnect the t/mister from the control board (the plug position is shown on the schematic pasted to the back of the fridge). This will allow the fridge to run wide open with no temperature control. If the fridge doesn't get to almost freezing, then you have other issues.