18th Jun 2016

Norcold Fault Codes LI OP, O, or 6 flashes (potential fire hazard!)

Is your refrigerator doing one of the following?

N610, N611, N810, N811
- front light flashing 6 times
N400, N410, N412, N500, N510, N512, N621, N622, N821, N822
- front display showing "O"
N641, N642, NX641, NXA641, N841, N842, NX841, NXA841, 1200, 1210, 1211, 2117, 2118
- front display showing "LI OP"

These codes appear when either your high temperature limit switch has been tripped or there has been a break in the connection at LIMIT IN and LIMIT OUT on the rear power board. The first thing we would recommend you do is to take a look at your power board by removing the power board cover. Look at LIMIT IN and LIMIT OUT on that board. If there are wires attached, they should lead you to a thermal switch. This switch is designed to trip power to the refrigerator if the temperature at the flu exceeds safe parameters. This is a safety precaution designed to prevent a fire. Don’t reset the thermal switch yourself. Resetting it without finding the cause is a fire risk. Check everything else first: AC ripple, the burner and flue, ventilation, the fans (if your model has them), and the cooling unit for signs of a leak (yellow, powdery residue or an ammonia smell). If the cooling unit is leaking, it has to be replaced. Resetting the switch is the last step, and we recommend a certified RV technician do it and test the fridge after it’s turned back on.

If you have a model refrigerator without a thermal switch, meaning there are no wires connected to the LIMIT IN and LIMIT OUT, you should have a small jumper wire going across that terminal. For those individuals, we recommend paying attention to how level you are when you camp. Cooling unit failures are caused from overheating which is often times just a result of accidentally running it off-level for extended periods of time.

Just replaced your power board? If your fridge has the jumper instead of a thermal switch, that jumper has to be moved from the old board to the new one. If it wasn’t, the new board will show this code right away. Move the jumper over (or install a new one across LIMIT IN and LIMIT OUT) and the code should clear.

For those of you with a thermal switch that has NOT gone off and yet you're still getting one of the codes above, this could be a problem with either your refrigerator power board or with dirty voltage being supplied to the refrigerator.

AC ripple can cause this code too. Dirty power from your converter can trip it even when nothing is overheating. Set your meter to AC volts and measure across the fridge’s 12V DC supply while plugged into shore power. More than 0.3 volts AC means the converter needs attention before you replace any fridge parts. See AC Ripple: The Silent Killer of RV Refrigerator Power Boards.

Step-by-step flowcharts: Norcold 1200 / 1210 L1 oP · Norcold N641 / N841 / N1095 L1 oP · Norcold 2118 oP LI