N also called a NO CO code. What that means is this. When the refer starts a cool down, there is a steady progression DOWN in temp-- 65-64-63 and so on. IF the refer does NOT complete an initial cool down within spec, then the refer assumes there is something wrong with the cooling system. This usually means something that can RUIN a cooling unit.
1. Out of level
2. LP flame not to spec/low gas pressure
3. low 120 voltage
4. restricted convection air from the bottom up the top on the back of the coils
5. If condenser fans are installed, they are not working
6. refer door not sealed adequately.
7. A bad cooling unit
When the N happens the refer will allow you 1 chance to turn it OFF wait 10 seconds and then turn it back on. IF THE CONDITIONS THAT TRIPPED THE CODE ARE NOT FIXED, THEN THE 2ND N CODE TRIPS AND IT LOCKS THE REFER OUT AND YOU HAVE TO DO A RESET PROCEDURE.
What this means is simple, there is something wrong with the system(NOT the main board), and you need to find and fix that condition. NOT to continue doing a reset. A BAD Thermister can cause this condition and is a cheap way to take it out of the loop. Since you do not know what is causing this problem and if the thermistor does not fix it, you need to get it to a qualified Technician to find the problem. Doug
