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Old 06-18-2019, 06:53 PM   #1
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Norcold 611 Troubleshooting

Hi all, been troubleshooting a Norcold 611 fridge, wanted to see what you all think:

Unit is fairly new (3.5 yrs old) in a 2016 Hurricane 29M. It's a combo AC/Propane fridge, not residential.

Fridge works great on AC. Does not cool on propane. I am always level so that is not the issue.

Propane lights, stays lit just fine. Flame is solid blue, no yellow/orange, no flickering, appears to be a good flame.

I've spoken to Norcold and a couple of mobile RV guys (one coming to the house tomorrow) and they are suggesting a few things, wanted to see what you think:

Norcold and 1 RV guy - says cooling unit itself is fine, because it works like it should on AC. Your thoughts?

Same 2 folks said it could be propane pressure (regulator). All my other propane appliance work perfect and my fridge flame looks strong, so I'm a little weary about this. Could this still be the issue?

All said it is likely NOT the oriface given the strong flame.

Norcold suggested it could also be a control board issue. Thoughts?



Leading up to today, I have had some intermittent issues on propane.

On 2 different camping trips in the last 9 mos, I have had the fridge get too warm during the trip. Was camping at the beach on both trips, so outside temperature was mild. Did some research, folks suggested testing the thermister by unplugging it. Unplugged it and overnight fridge got nice and cold. So I replaced the thermistor and all was good for another 4-5 camping trips.

Then, in the middle of another trip at the beach, fridge got warm again. So I unplugged the thermistor and after about 1.5 days the fridge was nice and cold again.

Strange to have a new thermistor go bad again and so soon?

So I got another new thermistor and put that in and this is where I am today. Fridge won't get cold at all on propane, with or without the thermistor connected. But it works great on AC, with or without the thermisor connected.

The thing I'm most concerned about is someone telling me I need the cooling unit rebuilt or need to buy a new fridge if that in fact is NOT the case.

Thoughts?
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Old 06-18-2019, 08:39 PM   #2
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To me, if the fridge/freezer works fine (maintains a relatively constant appropriately cold temp) on 120VAC then fridge portion is OK......including the thermostat sensor. If it does not work on propane only, even though the flame seems good (all blue), it sounds like not enough heat (BTUs) getting to the correct location on the ammonia tube in the flue/baffle/chimney space above the burner. Possible reasons for inadequate heat from the burner would be lower than normal propane pressure; partial blockage of oriface or burner tube (like soot, rust bits, dirt, bugs); flue/chimney blockage perhaps so inadequate draft. Does your fridge give any alarm codes on the control display when running on propane? Has the chimney ever been worked on or the AC element replaced ? Ever been cleaned out ?

What is the condition of your coach battery charge (12.6vdc wet cell unloaded is approx full charge)......when on shore power the converter is charging the coach batteries so DC voltage at the fridge cct board should be good; when on propane only (shore disconnected), if the coach batteries are discharged perhaps the fridge control board may not operate like it should.......you should get a Lo DC code for that though.

Not sure about the fridge control board being faulty for propane only......clearly it works for 120VAC operation you say......so to me you are changing the heat source, but the control temp sensing system should be basically the same (famous last words) not having a detailed schematic. Of course different switch contacts used etc.
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Old 06-18-2019, 09:29 PM   #3
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Quote:
Originally Posted by javelin View Post
To me, if the fridge/freezer works fine (maintains a relatively constant appropriately cold temp) on 120VAC then fridge portion is OK......including the thermostat sensor. If it does not work on propane only, even though the flame seems good (all blue), it sounds like not enough heat (BTUs) getting to the correct location on the ammonia tube in the flue/baffle/chimney space above the burner. Possible reasons for inadequate heat from the burner would be lower than normal propane pressure; partial blockage of oriface or burner tube (like soot, rust bits, dirt, bugs); flue/chimney blockage perhaps so inadequate draft. Does your fridge give any alarm codes on the control display when running on propane? Has the chimney ever been worked on or the AC element replaced ? Ever been cleaned out ?

What is the condition of your coach battery charge (12.6vdc wet cell unloaded is approx full charge)......when on shore power the converter is charging the coach batteries so DC voltage at the fridge cct board should be good; when on propane only (shore disconnected), if the coach batteries are discharged perhaps the fridge control board may not operate like it should.......you should get a Lo DC code for that though.

Not sure about the fridge control board being faulty for propane only......clearly it works for 120VAC operation you say......so to me you are changing the heat source, but the control temp sensing system should be basically the same (famous last words) not having a detailed schematic. Of course different switch contacts used etc.
Not throwing any codes, no flashing lights. Fridge is in the slide out, I have pulled the top outside vented panel and cannot see anything unusual. It's clean in there, but to your point I have not looked specifically into or cleaned the flu. I will check that tonight.
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Old 06-18-2019, 10:37 PM   #4
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I'm leaning towards that the cooling unit is fine. If not it would not work on electric. I would find a water column pressure gauge and test pressure. Minimum is 10.5 inches of water which is 0.37 PSI. The flame may look OK but if it's not enough BTU or propane feeding it you won't have enough heat for the cooling cycle. I would also clean out the burner assembly the flue. A pair of 12VDC pancake fans at the roof vent will help improve performance on either heat source.

My 6 cu/ft gave up two years ago but I still have the owners and service manual which will help. I had an obstruction in the piping between the freezer and fridge.
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Old 06-18-2019, 11:41 PM   #5
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Does the gas solenoid on the fridge control the propane pressure? Or is it the main propane regulator that is right off the propane tank?
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Old 06-19-2019, 12:56 AM   #6
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Usually the main tank regulator feeds all gas appliances. The regulator also must be able to respond to loading (multiple gas appliances running at the same time). The gas valve solenoid is basically an on off switch for gas.
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Old 06-19-2019, 07:42 PM   #7
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Tech came to the house today, the oriface was not flowing as freely as it should.

Cleaned it with alcohol and it flows freely now.

Also checked gas pressure, it was actually high at 15. He adjusted down to about 11.8.

The burner flame is slightly stronger looking now and I can actively hear the flame burning. Before it was not really audible.

Will check fridge temps is a few more hours to see if this takes care of it. Tech was confident that was the problem,
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Old 06-19-2019, 08:15 PM   #8
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Fingers crossed for your fix. Hopefully you watched the mobile tech with the cleaning process so you can do it for yourself in future as required. Thanks for letting the forum know what action was taken. Happy cooling.
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Old 06-20-2019, 05:32 AM   #9
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Unfortunately, it did not fix it. Tech says there is nothing left to check, doesnít understand why itís not working right.

Something is keeping the heat from properly exchanging on propane only. The freezer works great, got down to 3 degrees on propane but the fridge just kept warming up as the day went on. 59 at its coldest.

On electric, fridge gets to 31-33, freezer to -3.

Last suggestion by the Tech (who is a retired Norcold service rep) was to put a brand new burner/oriface in which I did about 2 hours ago.

Freezer is already down to 7 degrees but the fridge is only 69 (down from 81). Iíll check it in the morning but Iím not holding my breath.
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Old 06-20-2019, 10:24 AM   #10
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I would pull the fridge and check the entire burner, flue even the roof vent for anything that might be a problem with the flow of the heat from the burner. I'm trying to remember what the burner assembly looked like when I replaced my fridge. As I recall the electric element was up against to the tubing for direct heat conduction (or at least very close) while the propane flame had more of an air gap and was dependant on convection and good air flow with the heat rising thru the burner assembly and flue for transfer to the cooling unit. Either way if there is a cooling unit problem you'll need to pull the fridge to replace.

I made a stand that I could lift with a transmission jack to get the old fridge out and the new in. Made it real easy. Disconnected the propane line, unplugged electric and about six or eight screws and the fridge came out. Unfortunately I don't have any images of the old fridge but you can access every inch of the cooling unit other than the few sections that are buried in insulation. This will also give you full access to the burner and flue so you can do a detailed check. It could be something as simple as a piece of fiberglass insulation is blocking the heat from rising thru the flue/roof vent and you can't see it from the maintenance panel.

You could also put together the right pipe fittings, tubing and a low pressure regulator for full up test on propane with the fridge out of the alcove. Just incase I would also get the fridge out of the coach before attempting. Although the risk is small working with sub 1 psi propane it's still a risk in a close space such as a class A.
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Old 06-20-2019, 03:45 PM   #11
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Pleasant surprise this morning! Fridge 28, freezer 0!

Now I just hope it maintains. I can hear a random gargling sound coming from the flame, not sure what that is about. Iíll keep my fingers crossed!!
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Old 06-20-2019, 06:59 PM   #12
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I think it normally takes at least 4 hours or more depending on ambient outside temps to get the propane RV style fridges down to where they need to be. The DW turns fires up our Norcold fridge the evening before we are to start traveling so that by morning we are ready to pack the items needing refrigeration.
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Old 06-20-2019, 09:32 PM   #13
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Originally Posted by VetPartTimer View Post
Pleasant surprise this morning! Fridge 28, freezer 0!

Now I just hope it maintains. I can hear a random gargling sound coming from the flame, not sure what that is about. Iíll keep my fingers crossed!!
Well then disregard my last.
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