Fridge on Propane

I recently posted this question, but I think it was swallowed up by the techno glitzes that went on recently, so I will try again.

We went camping recently with the couple that bought our TM, and they had a question regarding the fridge operation on propane. Since they don't have a decent online connection, I thought I would post this question for them.

The TM is a 2003 model 2720 with a Norcold fridge, model N300.3. It starts and cools well on propane. But if the fridge gets too cold, and you turn the themorstat down until you hear the "click", the propane meter goes to the red and you have to manually restart it when the temperature gets back to the desired range. The fridge always worked that way for me, and I just thought it was normal. But now that they asked me about it, I was wondering if that is the way that it is intended to function and that is the way that it worked on other TMs.

Thanks in Advance,
Chap

That is not normal.

Norcold had a Service Bulletin that may solve the problem.

MY fridge would tern itself off. I never figured out why, but quite likely the same situation you are describing.

It is an electrical problem in the fridge.

[Bill]

Well, according to the Norcold manual, the CLICK you hear is the main gas valve ("safety valve") shutting off. Once this has happened, it requires a manual relight, just as you are seeing.

Question - is it possible to back off the setting a little less, to a point somewhat before you hear the click, and see if that helps to control the temp where you want it?

Wayne, as I recall, the electrical problem you refer to was a loose wire or crimp connector on the back of the thermostat. When this problem occurred, the refrig wouldn't light on gas at all. I don't think that's what Dave's people are experiencing.

Bill

When running on propane, my normal location for the control knob is prtty close to straight down.

As I rotate the knob back and forth across that setting I can hear it click. I can rotate the knob to position one, which is darn near off and then later rotate it back to 5, to freeze the lettuce. I never have to relight the fridge.

I use the click sound to determine the setting. If I want the fridge a little colder I rotate the knob towards one until I hear it click. Then I rotate it towards 5 until I hear it click again. That is where I stop, because it is now barely on, meaning just a bit colder that it was before I changed it.

You are probably right about the Service Bulletin. At least in terms of what they claim. My experience what that it was difficult to light, but once lit it would stay lit for an hour or two. I had to use my generator for the fridge that weekend.

[commodor47]

My experience running the refrigerator on propane is the same as Wayne's. I did have a problem keeping the refrigerator operational on propane, similar to Chap's description, and traced the cause to the wires connected to the safety valve button. Once the pilot light is lit, the unit should function as if it were on A/C power . . . that is, the thermostat will control the temperature. We typically set the thermostat at 3 for A/C and for propane operation. It is important to set the thermostat to 5 when starting the unit on propane. Within a few minutes of start, we set the thermostat to 3 and the refrigerator cycles to maintain the temperature as needed.

I corrected the safety valve button wire issue by carefully removing the two wires from the back of the button, applying a small amount of dielectric grease, gently squeezing the connector ends, and reconnecting the two wires to the back of the button. That fix was done 4 years ago and the refrigerator has worked perfectly on propane, to date.

Originally Posted by Bill

Well, according to the Norcold manual, the CLICK you hear is the main gas valve ("safety valve") shutting off. Once this has happened, it requires a manual relight, just as you are seeing.

Question - is it possible to back off the setting a little less, to a point somewhat before you hear the click, and see if that helps to control the temp where you want it?

Wayne, as I recall, the electrical problem you refer to was a loose wire or crimp connector on the back of the thermostat. When this problem occurred, the refrig wouldn't light on gas at all. I don't think that's what Dave's people are experiencing.

Bill

That is exactly what the TM that I had is doing. And that is the way that I figured that it should work when I owned the TM, and it made sense to me.

And I too remember the Norcold Service bulletin as the fridge refusing to light on propane, so I don’t think that would apply in this application, as the fridge lites OK on propane.

Originally Posted by PopBeavers

As I rotate the knob back and forth across that setting I can hear it click. I can rotate the knob to position one, which is darn near off and then later rotate it back to 5, to freeze the lettuce. I never have to relight the fridge.

I use the click sound to determine the setting. If I want the fridge a little colder I rotate the knob towards one until I hear it click. Then I rotate it towards 5 until I hear it click again. That is where I stop, because it is now barely on, meaning just a bit colder that it was before I changed it.

That is the way the new owners thought it should work.

Originally Posted by commodor47

My experience running the refrigerator on propane is the same as Wayne's. I did have a problem keeping the refrigerator operational on propane, similar to Chap's description, and traced the cause to the wires connected to the safety valve button. Once the pilot light is lit, the unit should function as if it were on A/C power . . . that is, the thermostat will control the temperature. We typically set the thermostat at 3 for A/C and for propane operation. It is important to set the thermostat to 5 when starting the unit on propane. Within a few minutes of start, we set the thermostat to 3 and the refrigerator cycles to maintain the temperature as needed.

I corrected the safety valve button wire issue by carefully removing the two wires from the back of the button, applying a small amount of dielectric grease, gently squeezing the connector ends, and reconnecting the two wires to the back of the button. That fix was done 4 years ago and the refrigerator has worked perfectly on propane, to date.

Commodor47, since you have a 2003 model TM, then that should prove that the 2003 that I had should probably work the same way. I did not realize that the fridge had a pilot light. So, if you cut the themostat back, does the gauge go to the red when the main flame goes out, and the pilot is still on ???

Commodor 47, if you and others observe how the propane meter works when the themostat clicks off, then that will really help me and the new owners maybe find a solution here. If it goes down to towards the red on y’all’s, then maybe the fridge that I had will again pick up when the thermostat calls for a colder temperature….meaning the new owners need to wait until that happens. If the meter doesn't go down after the themostat clicks off, then maybe the pilot light isn't lighting, or staying lit.

Thanks for all of the input, and maybe we can get this (possible) problem diagnosed and fixed.

Chap

Bottom line is, once you light the fridge, it should remain lit until:

1. you turn it off
2. you run out of propane
3. it malfunctions

Sounds like you have encountered situation number 3.

Quite likely there is not enough electric power from the thermocouple to keep the gas valve open. Once that valve closes you lose the flame.

There are several different things that could be causing this:

1. wiring or connection problem
2. weak thermocouple
3. bad gas valve

there may be other causes that I can not think of.

[Bill]

Wayne -

The other cause, of course, is that the thermocouple has moved a bit, and is no longer bathed in the flame. When the refrigerator cooling at full throttle, the flame is quite big, and a small position error won't cause a problem. But when you turn back the thermostat a bit, the gas cuts back to idling, and the flame becomes quite small. The thermocouple must still be bathed in this small flame. If it is not, CLICK!

Fortunately, of all the problems considered, this is probably the easiest problem to solve - look for the picture in your refrigerator owner's manual.

Bill

PopBeavers pretty well has it down. You may try cleaning the thermocouple.
On my 2007 there is no pilot light on the fridge. Once it’s lit it stays lit. The temp is controlled by the flame size, same as your stove top burners. That’s the reason it lights so much easier when it’s set to “5” ( more gas flow), then turned down to your preferred setting. The red/green gauge is a temp. reading from a sensor next to the flame. The fridge will work without it (the gauge). The sensor also controls the gas valve, when it’s hot, it keeps the main gas valve open. If the flame goes out, it cools and the valve shuts. If it’s dropping into the red either there is a loose connection in the wiring to the gauge and the fridge is still working or, the gas flow to the fridge quit and it will have to be relit. If you turn the temp setting all the way up or down you can watch the meter go higher or lower into the green as the flame go higher or lower. You can also verify this by being outside and watching the burner flame as some one inside the TM turns the control up and down. The clicking is the thermostat that controls the AC operation of the fridge. It gives a good indication of the temp inside the fridge but it has nothing to do with the operation on gas.
Hope I haven't confused anyone, it's early and I haven't had my second cup of coffee yet.

[commodor47]

Originally Posted by mtnguy

. . . I did not realize that the fridge had a pilot light.

As Digger points out in his post, there is no pilot light per say - it is easy to confuse the small flame associated with a low temperature setting for a pilot light.

So, if you cut the themostat back, does the gauge go to the red when the main flame goes out, and the pilot is still on ???

Sorry for the confusion here . . . there is only one flame. If it goes out then the meter does move into the red zone.

Commodor 47, if you and others observe how the propane meter works when the themostat clicks off, then that will really help me and the new owners maybe find a solution here. If it goes down to towards the red on y’all’s, then maybe the fridge that I had will again pick up when the thermostat calls for a colder temperature….meaning the new owners need to wait until that happens. If the meter doesn't go down after the themostat clicks off, then maybe the pilot light isn't lighting, or staying lit.

Both Digger and Wayne have aptly described how the refrigerator should work on propane. I have observed the meter move all the way to the end of the green zone when running on propane. Digger did shake my memory cells when he noted that how far the meter travels into the green zone is a function of the flame size, which is a result of the thermostat setting. I agree with Wayne's suggested remedies. If your meter is dropping off into the red zone the flame is out. That is easy to verify visually. My refrigerator exhibited the same inconsistent operation you describe Chap. Sometimes it would run for several hours then shut down; other times it would shut down within a few minutes. But since I added dielectric grease to the push-on spade connectors on the safety valve wires the refrigerator has worked perfectly on propane.

Dick