Norcold Not Cold on LP

[jburnside]

I’ve got a Norcold 1211IM (high serial #) in my 2014 Itasca Sunstar 35F that gets warm on LP after a few days running. The cooling unit was replaced a year ago after a blowout failure. We dry camp most of the time.

We took a 6 week trip in June and stayed in RV parks for a lot of it. The refrigerator worked fine on 120 VAC and I have to admit I could get used to the constant air conditioning and princess showers that come with hookups. We dry camped in Glacier NP for a week and noticed the temp in the refrigerator had climbed to 50 one morning a few days in. Freezer was 26 – 30. I checked the burner assembly and noticed the flame sensor was a bright orange color as it deflected the flame. I pulled the sensor and scraped some carbon from it with my fingernail which revealed some damage or wear into the substrate. The flame burned blue upon replacement but the orange glow returned the following morning. The refrigerator temp would drop below 40 with the generator running, but quiet hours got in the way of that solution. We bought ice blocks for the bottom tray to get us through the week.

We stayed in RV parks for most of the rest of our trip but ran into a couple of parks with “unreliable” power pedestals during the record heat wave. The higher refrigerator temps would return when the mode switched over to LP due to power outages or voltage drops.

I searched this Forum and downloaded the Norcold 1200 service manual (thanks rayin) to figure this thing out. No fault codes were displayed on the Optical Control Assembly but the Diagnostic Mode Screens 4 & 5 did have a few stored faults like Door Ajar, low DC voltage, etc., which were consistent with our experiences. Screen 5 would usually show Segment 7 lit which shouldn’t happen according to the 1200 manual. Segment 7 on Screen 4 is AC Heater Failed Open but I don’t know if this would be the same or something different on Screen 5. Screen 8 Power Board Outputs usually shows Segment 3 DC power to divider heater lit.

Once we got home and recovered from our long journey, I fired the Nocold back up on LP and let it run for a couple weeks while tracking the temperatures in each compartment. I started out with temperature setting 8 which rendered freezing conditions in the refrigerator. About 5 days in the refrigerator hit 52 and I could really feel the heat coming from the divider between the freezer and refrigerator. There were no faults stored and the Power Board Outputs indicated DC power to Divider Heater. I turned the temp setting down to 5 where we usually run it and watched it for a couple more days. On the second day the refrigerator temp hit 74 with an ambient temperature of 71. The divider was extremely warm and the cooler fans were cranking. The refrigerator started cooling down to ambient temp as I held the door open. I cleared the codes (screen 5 segment 7) and cycled the unit off/on. The temps were good for the next few days before I had to shut it down because my propane tank was almost empty. During this test period, Screen 4 Segment 5 AC mode selected but not available was lit but I had never tried for AC mode as my RV is parked in a storage lot.

Questions:

Does the 1200 service manual apply to my 1211 model or is there another manual I should be looking for?

Do the stored fault codes on Diagnostic Screens 4 & 5 have any operational control logic or are they just informational? Does clearing them reset the unit?

What does Segment 7 on Screen 5 indicate on 1211 model?

Does the flame sensor work OK with surface damage or does it do more than sense flame?

Is the divider heater always energized or should it only come on in a defrost cycle?

How is the defrost cycle triggered?

Can anyone recommend a relatively low cost temperature logging device to track changes over time?

[rayin]

The flame sensor has an additional function of supplying the spark to ignite LP, then the flame temperature generates about 14 millivolts to hold the gas valve open. You know the flame sensor is working because he flame remains lit,  if it is faulty the flame will not remain lit. just use Scotch-brite to shine it up and replace it.

Here is the Norcold 1211 service manual. On the same website is the installation instructions for constructing the chimney so the proper convection occurs, when the chimney is ill-constructed the cooling unit over-heats, resulting in cooling unit failure.

The divider and defrost cycles are set by the control board. I don't remember more, but I think I remember reading the 12V+ wire to the flapper can be cut and a switch inserted to conserve battery power. The service manual should address that.

Have you got a fan on the back of the fridge blowing upward on the coils to improve ventilation? This is especially important if your fridge is in a slide.  If the coolant mixture does not dissipate heat quickly enough, your condition is what happens  You can buy a small blower type 12V fan for less than $10, which will move much more air than a muffin - computer type fan.  I have one on the back of my 1200 LRIM that works great. 

 

 

Edited October 7, 2023 by rayin

[jburnside]

THANK YOU Rayin! Just gave the 1211 service manual a quick review and it turns out the diagnostic screens do have subtle differences from the 1200 manual indicating potential venting issues. My segment 7 query points to the high limit switch tripping without a lockout or displayed fault code.  

My unit is not in a slide out. I do have the fans below the condenser but will look into installing the blower you suggested as well. When I got my coach back from having the new cooling unit installed last year, I remember thinking that there were some baffles missing that had been there before. Unfortunately, I hadn't captured any pictures of it prior to the work being done. I did notice that I could hear the cooling fans much more prominently while sitting in the adjoining bathroom and the burner seemed to run longer and throw more heat from the exterior service door.

It is starting to make more sense. I'll touch back when I figure it out.

[jburnside]

Got this figured out after chatting with the certified Norcold tech at the local RV shop that replaced my cooling unit last year. I was thinking I might have a chimney issue after pulling the cap off the roof and not seeing a deflector shield on the top of the unit. I fished a length of 14 gauge copper wire through the screen and swung it towards the front of the refrigerator and found the deflector a couple of inches back where Winnebago had originally installed it. The Norcold installation instructions recommended the shield be placed flush to the back of the refrigerator extending up to the roof cutout so I was thinking the heat might not be exhausting as efficiently as it should. However, this situation would have caused problems years ago and it hadn't.

The Norcold tech told me that a chimney issue would present when running on 120 VAC too so his guess would be either a dirty burner or a bad gas regulator since I was only having problems running on LP. He said the older burners were chromed and tended to get all roughed up over time leading to a dirty flame and regulators tended to relax over 10 years old. I don't have a manometer yet so I bought a new burner off him and headed home. I pulled the old burner and sure enough, the edges were rough and not sharp and crisp as the technician said they should be. I probably could have wire brushed the old one and gone with that but I had the new one in hand at a reasonable cost so in it went. The swap out was about a 15 minute job. I cleaned up the old burner to keep as a spare and ran the refrigerator for a week with no more issues. We are ready for the road again.

Thanks again for your assistance Rayin. I am still thinking the blower fan on the cooling unit is a good idea and will likely install one soon. Where did you connect yours too? Did you connect directly to the power board, splice into the condenser fans wiring, or pull 12VDC from somewhere else? Did you use a solenoid switch or does it run nonstop?

 

[rayin]

jburnside; my blower-type fan is controlled by a button thermostat clamped to the cooling unit piping; it is an addition to the Fridge Defend/ ARP unit I installed to protect the cooling unit  from overheating. I suggest you read up on it's function and safety features.