Norcold Fridge Thermocouple

Wavery · 01-24-2011, 02:45 PM

Has anyone replaced the thermocouple in their Norcold fridge?

This weekend our fridge would not stay lit. The burner would light but no matter how long I held down the gas button, the burner would go out when I released the gas button.

I hate to say this but I finally pushed the gas button in and put a screw in the gap between the button and the housing to keep the button depressed and the burner going. I left it that way all weekend. There was no wind so I wasn't concerned about the burner going out. I still didn't like doing that though (and I certainly don't recommend doing that).

I'm fairly confident that the thermocouple is bad. I tried cleaning it as best I could and that didn't help. It doesn't look like fun to replace that thing and I am hoping to get some tips from someone that has already done it.

**commodor47** · 01-24-2011, 05:06 PM

Wayne,

I've had a similar issue with our refrigerator. Turns out it is caused by oxidation on the gas button terminals. If you remove the radio, the two terminals are accessible. Carefully remove each, clean, add a little dielectric grease and make sure the connectors are snug.

Dick

Wavery · 01-24-2011, 05:14 PM

Quote:

Originally Posted by commodor47

Wayne,

I've had a similar issue with our refrigerator. Turns out it is caused by oxidation on the gas button terminals. If you remove the radio, the two terminals are accessible. Carefully remove each, clean, add a little dielectric grease and make sure the connectors are snug.

Dick

I'll try it but I don't see how that could be the issue. The burner runs perfectly as long as the button is pushed in. That seems to indicate that the switch (button) is working fine. Am I missing something here?

**commodor47** · 01-24-2011, 05:24 PM

This thread may explain it better:

http://www.trailmanorowners.com/foru...t=refrigerator

Dick

**Bill** · 01-24-2011, 06:30 PM

You can check the thermocouple with a good voltmeter - and you have one, as I recall.

The thermocouple is actually a small thermo-electrical generator. When it is hot, it generates a small fistful of millivolts. My memory is hazy, but I'm thinking on the order of 20-30 mV?? You should look it up, rather than taking my word for it. Anyway, this very small voltage operates the gas valve.

If you see these hot millivolts, then the thermocouple is good. If it generates no millivolts, then it is probably bad.

Bill

**rickst29** · 01-24-2011, 07:57 PM

Quote:

Originally Posted by Bill

You can check the thermocouple with a good voltmeter - and you have one, as I recall.

The thermocouple is actually a small thermo-electrical generator. When it is hot, it will generate a small fistful of millivolts. My memory is hazy, but I'm thinking on the order of 20-30 mV?? You should look it up, rather than taking my word for it.

Wayne, I don't know if your 2004 contains a "genuine N300.3", or whether it's a preceding model with substantial differences. But if it's a "modern" N300 3-way, like mine, then you should use the flowchart on page 10 of the Service Manual. (That's the one named "Burner Ignites but Cannot Maintain Flame.")

We've got the manual, right here on TMO: http://www.trailmanorowners.com/foru...7&d=1268332435

As you see from the chart, you replace the thermocouple for one combination of voltage readings; the interrupter on a second combination; and the safety valve on a couple of others. It would just be a shame to buy a new thermocouple, and then discover that the problem was elsewhere. So use the chart! That's why I uploaded the manual.

scrubjaysnest · 01-24-2011, 06:43 PM

The thermocouple is a very low millivolt output device, think in terms of battery connections and charging from the TV. Any corrosion will make the flame meter think there is none. Both the flame meter and the thermocouple interrupter are wired at the same point according to my Norcold manual. I'd try cleaning those connections first.

Wavery · 01-24-2011, 06:56 PM

OK.......now that I have thought the problem though better. Thanks for all of the links. I didn't know that Norcold had a bulletin covering this very issue. It seems that the N300 series fridges built in 2004 had some defective wiring issues and they supply a new wiring kit as a fix.

I hadn't even considered something like that because I'm so used to thermocouples going bad and replacing them. I've done it on a couple of water heaters and about 5 or 6 fireplaces in our apt building over the years.

Boy, I sure would have hated myself if I went to all that work and it didn't fix the problem. I appreciate all the brain storming that goes one here.

I'll go down and check the voltage on the thermocouple in the morning, just to be sure. If the voltage is OK, I will call Norcold with my serial number and see how it goes. Seems like there have been mixed results. I'll keep this thread updated as I progress through this.

Thanks guys......