Fridge propane troubleshooting - looking for input

[ttavasc]

I picked up my trailer earlier today from the service place where they were looking at the fridge not cooling properly on propane. The freezer would get somewhat cold but the main compartment, even after running for several hours on propane would still be about room temp. I fired it up when I got it back home and it does seem like they improved the situation some, but I think it's still not working quite the way it should be. It works great on electric so I know that the cooling unit on the fridge is working properly. I do have a vent fan installed to improve the flow of air over the back of the fridge.

So I'm gearing up to do some additional troubleshooting - I need to learn how to do more of this stuff myself anyway. Prior to dropping it off at the dealer I cleaned the burner and chimney assembly, ensured the spiral baffle was in the correct place as well as cleaned the burner orifice per the service manual procedure. I've got a manometer coming from Amazon in a couple of days so I can test the pressure to the various appliances. I've also got a digital volt meter I keep in the trailer so I can test the thermocouple too.

Regarding the thermocouple - the test instructions that I've looked at indicate that if it doesn't register at least 20 millivolts it should be replaced. My fridge is a manual ignition - there is no pilot light. Is it possible that if the thermocouple is starting to have issues it could be causing a minor restriction in the flow of gas as opposed to completely shutting it off?

Regarding the main regulator on the front of the trailer - if the pressure throughout the system is low - less than 11.5 column inches I believe - would it be recommended to adjust the pressure on the existing regulator or would it be better to just replace the regulator. It's the original regulator that came with the trailer.

I've not smelled any leaks in the propane system but I do keep on hand some leak detection fluid to use after connections are closed up and tightened again. I suppose that if the pressure is slightly low I could have a leak somewhere as well so I should check all the connections I can find before adjusting/replacing the regulator.

Anything else that I could or should be looking at regarding the propane system on the fridge? Appreciate any input provided as I'm sure I've overlooked something.

[Fr8Train]

I would assume the service folks would've checked, but I've seen/heard of critters getting in the gas line causing problems. Mud daubers, spiders, etc.

[DanNJanice]

Originally Posted by ttavasc

I picked up my trailer earlier today from the service place where they were looking at the fridge not cooling properly on propane. The freezer would get somewhat cold but the main compartment, even after running for several hours on propane would still be about room temp. I fired it up when I got it back home and it does seem like they improved the situation some, but I think it's still not working quite the way it should be. It works great on electric so I know that the cooling unit on the fridge is working properly. I do have a vent fan installed to improve the flow of air over the back of the fridge.

So I'm gearing up to do some additional troubleshooting - I need to learn how to do more of this stuff myself anyway. Prior to dropping it off at the dealer I cleaned the burner and chimney assembly, ensured the spiral baffle was in the correct place as well as cleaned the burner orifice per the service manual procedure. I've got a manometer coming from Amazon in a couple of days so I can test the pressure to the various appliances. I've also got a digital volt meter I keep in the trailer so I can test the thermocouple too.

Regarding the thermocouple - the test instructions that I've looked at indicate that if it doesn't register at least 20 millivolts it should be replaced. My fridge is a manual ignition - there is no pilot light. Is it possible that if the thermocouple is starting to have issues it could be causing a minor restriction in the flow of gas as opposed to completely shutting it off?

Regarding the main regulator on the front of the trailer - if the pressure throughout the system is low - less than 11.5 column inches I believe - would it be recommended to adjust the pressure on the existing regulator or would it be better to just replace the regulator. It's the original regulator that came with the trailer.

I've not smelled any leaks in the propane system but I do keep on hand some leak detection fluid to use after connections are closed up and tightened again. I suppose that if the pressure is slightly low I could have a leak somewhere as well so I should check all the connections I can find before adjusting/replacing the regulator.

Anything else that I could or should be looking at regarding the propane system on the fridge? Appreciate any input provided as I'm sure I've overlooked something.

I think you are on the right track. Since it works well on AC, you have pretty much eliminated everything except the burner components. As others have stated, spiders seem to love propane lines. I had a gas fireplace that had a low flame, one year because spider built a web in it.

You might take a look here Service Documents and Manuals
It has service manual for many types of refridgerators.

[Marcm157]

In my experience a thermocouple is either good or bad. I haven't seen one that fails slowly.

[ttavasc]

Originally Posted by Fr8Train

I would assume the service folks would've checked, but I've seen/heard of critters getting in the gas line causing problems. Mud daubers, spiders, etc.

I made the same assumption. I do need to add screens to my fridge vents - it's been on my list for a while but have not yet gotten to it. Maybe before I cover it at the end of this season.

[Fr8Train]

You know what they say about the word assume....

[ttavasc]

Originally Posted by DanNJanice

I think you are on the right track. Since it works well on AC, you have pretty much eliminated everything except the burner components. As others have stated, spiders seem to love propane lines. I had a gas fireplace that had a low flame, one year because spider built a web in it.

You might take a look here Service Documents and Manuals
It has service manual for many types of refridgerators.

I checked out the manuals on the link provided. Looks like the Norcold N300 one was newer than the one I had come across elsewhere, so I downloaded the newer one. Thanks!

[ttavasc]

Originally Posted by Fr8Train

You know what they say about the word assume....

Yes - that's very true. I based my assumption on the service description which included a "propane system diagnostic". Shame on me if that's just a "marketing" gimmick... All the more reason for me to learn how to do more of my own troubleshooting and repairs.....

[ttavasc]

Originally Posted by Marcm157

In my experience a thermocouple is either good or bad. I haven't seen one that fails slowly.

I've been getting that impression as I look into them more. I did have problems with the one on my water heater, which does have a pilot light, last season. The "fix" was to pull it and clean it up with some sand paper. Haven't had any issues with it since I did that.

Of course I did run a test on the fridge after getting it set back up at the house. The short of it is that letting it run overnight did confirm that it was cooling on propane again. When I checked the next morning it was in the low 30's where I would expect it to be.

The part that leads me to believe that it's not working as well as it should be is it used to cool faster on propane that electric. Now that's reversed - and noticeably so. If I fire it up on electric with the main compartment temp around 70 - in about 2 hours it will have dropped about 15 degrees. Same starting point on propane and after 2 hours it has dropped less than 5 degrees. After 4 hours on electric it will be in the upper 30's to 40. On propane it will be around 50-55.

We are heading out for a few days at the coast this next week so I'm planning to run it on propane even though we have electric hook ups. I need to get an idea of how well it is going to do because we have another longer trip coming up just after Labor day where a portion of the time we won't have any hook-ups. That's the one I've been worrying about - 8 days/1600 miles and we made reservations last fall so I don't want to be derailed because the fridge isn't working. If it seems to be OK for the trip next week then I'll probably not dig into it further until after the longer trip.

[DanNJanice]

Everything you have said would make me suspect a problem with the gas flow or flame position. My Norcold 811 does seem to cool better on propane, but I have never attempted to measure the difference.
However, the cooling rates you are talking about are pretty good. I would not expect an absorption refrigerator to reach fully cold any faster that 4-8 hrs.

[pamanc]

Ours takes a good 12 hours to get to maximum cooling


Sent from my iPhone using Tapatalk Pro

[ttavasc]

Originally Posted by DanNJanice

Everything you have said would make me suspect a problem with the gas flow or flame position. My Norcold 811 does seem to cool better on propane, but I have never attempted to measure the difference.
However, the cooling rates you are talking about are pretty good. I would not expect an absorption refrigerator to reach fully cold any faster that 4-8 hrs.

Since I got it back from the dealer I would agree that it does appear to be working pretty well. I mean, it's actually working again which it wasn't before I took it in. But it definitely doesn't work as good on propane as it did before our last trip when it failed to cool at all on propane. I do wonder if excessive heat had anything to do with it. It quit working on the drive home which was a bit more than a day and a half in around 100 degree temps.

At any rate, this is a good opportunity to learn more about this part of the camper and how to troubleshoot/maintain it. I certainly do appreciate everyone's comments and feedback.

[SloPoke]

Originally Posted by ttavasc

I do have a vent fan installed to improve the flow of air over the back of the fridge.
.

Is the fan drawing air out of the top vent? or is it moving air around behind the fridge?

The most efficient method is to place the fan in the exhaust hood at the roof vent and assist in the convection process. Having the fan drawing out the hot air from the fridge cabinet so that it can bring in fresh air in the lower vent.

Drawing air over the condenser coil at the top of the fridge is the most beneficial air movement, along with insuring that the baffle is placed properly around that coil.

[ttavasc]

It's a side vent unit, not a roof vent. I have the fan installed in the top vent above the coils to pull the air up from the bottom vent. It has a thermistor on it that kicks it on above 110 degrees and then off when it drops below 90 degrees. In hotter weather it seldom kicks off - in more moderate temps it may run half the time or less. I think the side vent for exhausting the hot air is less efficient than a roof vent, especially when rolling down the freeway at 60.

[Campers & Fishers]

In my experience, the gas fridge that has a seperate freezing compartment directs almost all of the start up cooling to the freezer. When the freezer is cooled to spec. then it directs cooling to the lower box.
And fridges that have been off all winter will require a longer time to get to temp. Mine takes a couple of days at least to to begin to work right. Then, it's pretty good.
good luck....

[Atlee]

Take off the cover to the refrigerator on the outside of the RV. Sniff around to see if you get the faint "aroma" of ammonia. If you do, it means your fridge is done for.