611LT is throwing the NOCO fault for 3 weeks now. Every other time we can get it to cool on either AC or propane

Question

611LT is throwing the NOCO fault for 3 weeks now. Every other time we can get it to cool on either AC or propane

So unlike the usual situation where it requires a reset through the pin 15 and ground every time the NOCO fault is shown we can get it to restart the cooling process by just switching the reefer off using the eyebrow switch. I have replaced the circuit board (PN 621991001 from Amazon) and problem persists. Thermistor seems to be working as expected based on resistance readings at hot (8000 ohmns) and cold (30000 ohmns). Propane flame is present when that is switched on. Doors don't seem to have any issues.

Status: Open Sep 26, 2026 - 07:19 AM

Do you have the same question? Follow this Question

Report it

1answer

Staff Answer

Sep 26, 2026 - 07:19 AM

Since the board and thermistor check out and it restarts with the eyebrow switch, the NO CO fault itself is the clue. The board is shutting down because it isn't seeing the cooling it expects after heating. That points to a cooling unit that's getting weak or partially blocked, even if it cools some of the time. See our "no CO" fault article. If the cooling unit is failing, we carry the Nordic Cooling Unit 3361A for the N611. The N611 is discontinued, and Norcold's replacement is the Norcold N7X. See our Norcold replacement guide.

If you have any questions, just reach out at info@rvfridgeguys.com or call us at 800-712-8822. You can find everything we carry at www.rvfridgeguys.com.

Report it

Browse by Category

Norcold N611, N621, N641

View our complete selection of Norcold N611, N621, N641 to find the one that suites your needs.

View All

View all Norcold N611, N621, N641 Questions & Answers

Browse by Category

Tools