13th Oct 2026
Norcold 1200 / 1210 L1 oP Code (High Temperature Limit Switch Open)
L1 oP CODE
Norcold 1200 / 1210 L1 oP Code (High Temperature Limit Switch Open)
The display alternates between L1 and oP and the alarm beeps. The high temperature limit switch on the cooling unit boiler is open or disconnected. It opens when the boiler gets hotter than 378°F (192°C), to protect against overheating. Resetting it gets you running again, but you still need to find out why it got that hot.
Before you start
- Level first. Make sure the RV is parked level. Running off-level is a common cause of overheating on absorption fridges.
- Resettable or not? If your switch is resettable, reset it. If it’s the older non-resettable type, Norcold says to replace it with a resettable switch. Either way, work through the steps below.
- Where it is. On the cooling unit’s boiler canister, behind the lower outside vent.
STEP 1
Think back
Before L1 oP showed up, was the fridge cooling normally?
Was the fridge cooling before the code appeared?
Reset the switch and test cooling
Reset or replace the high temperature limit switch, then test cooling on both AC and LP. If it still won’t cool on either, see what causes cooling unit failures.
Norcold High Temp Limit Switch 637360 →Resettable switch on the cooling unit boiler. Fits the 1210.STEP 2
Look at the burner area
Check the burner and flue area for signs of overheating (blue).
Did the burner overheat (blue)?
Reset the switch and test cooling
No sign of burner overheating. Reset or replace the high temperature limit switch, then test cooling on both AC and LP.
STEP 3
Check for insulation in the way
Look at the heat deflector cap on top of the flue and at the burner box.
Is the heat deflector cap or burner box blocked with insulation?
Clear the insulation
Pull the insulation away from the deflector cap and burner box. Reset or replace the limit switch, then set the controls to LP and test cooling.
NOT THE BURNER
Check the airflow and the fans that move it.
STEP 4
Check the airflow
Look at the roof or side vent and the lower vent, and the space behind the fridge. Anything blocking air from moving through the enclosure counts: leaves, nests, stored items, loose insulation.
Is something blocking airflow through the enclosure?
Clear the obstructions
Clear everything out of the vent path. Then reset or replace the high temperature limit switch, and test cooling on both AC and LP. See why venting matters.
STEP 5
Check the fans
With the fridge running, check that the cooling fans behind the fridge spin when the back gets hot.
Are the fans okay?
Replace the fans
Replace the cooling fans (two per fridge). Then reset or replace the high temperature limit switch, and test cooling on both AC and LP. ask a tech to match the right fans to your serial number.
STEP 6
Check the fan switch
The fan thermostatic switch turns the fans on when the cooling unit gets hot. Test that it closes when heated.
Is the fan switch okay?
Replace the fan thermostat
Replace the fan thermostatic switch. Then reset or replace the high temperature limit switch, and test cooling on both AC and LP.
Norcold Fan Thermostat 640235 →Turns on the rear cooling fans. Service replacement 638278. Norcold High Temp Limit Switch 637360 →Resettable switch on the cooling unit boiler. Fits the 1210.Check the cooling unit
The burner, venting and fans all check out, so the cooling unit itself may be overheating. Test cooling performance, and see what causes cooling unit failures before you replace it.
Norcold Nordic Cooling Unit 6610 →Replaces the discontinued OEM 634746 and 634747. Fits the 1200 and 1210.Still stuck? ask a tech with your model, serial number and the readings you got. We’ll confirm the part before you order.
Based on the Norcold 1200/1210 service manual, L1 oP Code (Open High Temperature Limit Switch) flowchart.