Norcold NO CO, n or Flashing 5 Times: What the Lockout Code Means and How to Reset It

The short version

• NO CO, n and flashing 5 times are Norcold’s “no cooling” lockout. Which one you see depends on your model (table below).
• It’s a safety shutdown. If a cooling unit keeps heating while its solution isn’t circulating, it can overheat and start a fire.
• Your power board is usually not the problem. It’s doing its job.
• Check the cooling unit for warning signs first, then reset the board and find the cause. A plain reset just brings the code back.

Your model	Lockout code
1200, 1210, 1211	Display shows no co
2117, 2118	Display shows no co
N641, N841 (and NX / NXA / IM versions)	Display shows no co
N621, N821	Display shows n
N400, N410, N500, N510	Display shows n
N611, N811	Front light flashes 5 times

Polar N7X / N8X flashing 5 times is a different fault

On the N7X / N8X, 5 flashes means a flame-sensed fault, not a cooling lockout. Use the N7X/N8X flashing five times flowchart instead.

STEP 1

Look for signs of a leaking cooling unit

Open the lower outside vent and look at the back of the fridge. Yellow powder or residue, or an ammonia smell, means the cooling unit has leaked. Turn the fridge off (gas and electric) and don’t reset it.

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Yellow residue or ammonia smell?

STEP 2

Reset the power board

Follow the lockout reset guide. You jump a reset pin on the power board to ground for about 10 seconds with the fridge on and showing the code. If it won’t clear, see power board won’t reset.

STEP 3

Find out why it locked out

Norcold’s list of common causes: poor ventilation, the RV off level (limits are 3° side to side and 6° front to back), a dirty burner, low AC voltage, a failed cooling fan, improper installation or the wrong orifice. Fix what you find before you rely on the fridge again.

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Code comes back after a reset and those checks?

Parts for this repair

Shop by category: Norcold fans, Norcold burners & orifices, Norcold AC heaters.

What does NO CO mean on a Norcold refrigerator?

No cooling. The fridge didn’t sense the temperature drop it expected, so it shut down for safety. 1200, 1210, 2117, 2118, N641 and N841 models show “no co”.

Can I just reset the board?

You can, but if the cause isn’t fixed the code comes back. Check the cooling unit for residue or an ammonia smell first, then reset and work through the causes.

My N621 shows “n”. Is that the same thing?

Yes. N621, N821 and the N400/N500 series show “n” for the same no-cooling lockout. N611/N811 flash the front light 5 times.

Lockout reset guide   Norcold error codes   Error code lookup
Still stuck? Ask a tech with your model, serial number and what you’ve found. We’ll confirm the part before you order.
Model codes and causes from Norcold service information. Updated October 2026.