Nor cold n811 codes

There is no 6X code.

ON LED Flashing
5X is no cooling detected by controls (ventilation or board needs reset ----same as a 'no co' fault)
4X is controls failure (replace board)
3X is AC heater failure (element bad or board)
2X is Mode switch failure (replace optical control assembly)
1X is Backup system operation (thermistor disconnected or failed)

ON LED on & GAS LED Flashing
1X is Gas Lock-out (Ignition/flame failure)

ON LED & GAS LED both flashing
1X is IF in 'Auto' no AC Power OR LP gas available
1X is IF in GAS Mode......no ignition

ON LED Off
Fridge turned off
NO 12V DC
DC Fuse blown

You wasted money. 5 flashes means that it still has the lock out code from when your cooling unit failed. That means the refer tried to cool down twice and each time it could NOT due to the bad cooling unit and it locked out the control board. That means you have to do a HARD reset. Now, you purchased a new board, but there is NO 6 flash code I am aware of. The new board would be a Virgin board and not have the lock out code. You have 1 chance to avoid lockout. If the Refer does NOT sense a cool down cycle it will lock oiut and throw the 5 flashes. You then get 1 bite. Turn the refer OFF for 10 seconds, FIND the reason for the lack of cool down, correct it and start again. IF you did NOT correct the 1st fault, then the 2nd try will lock out the control board. So, I suspect you tried twice and you have a 5 flash code not 6. I also suspect you have NOT either installed the New CU correctly or you have some wires not connected correctly. Doug

Page 21 or 24 depending on how your PC counts the pages.

http://bryantrv.com/docs2/docs/ncoldnnewnseries.pdf

Moved to Tech Issues forum from 5th Wheel forum.