Current limiting resistor for LED or other loads

Limit Circuit Open. Limit circuit open or External Load on "W" Nordyne/Intertherm M3RL080A Here is what I have done so far (most as part of general service): Changed 2 x limit switch Changed Pressure switch Changed ignitor Changed flame sensor Changed board Anyone any ideas with these furnaces as to why it would still throw this code after this? A 4-flash code can be for an open main limit or an auxiliary limit

The wiring diagram also shows a stack-over limit switch that may be tripping limit circuit open I have Gibson furnace, fan blows but no heat

Limit Switch Explained Working Principles YouTube

I have found in most cases the limit switch is fine. Have a customer with a ICP high efficiency furnace, throwing a 4 flashing light code, limit switch open I have found in most cases the limit switch is fine.

Limit circuit open or External Load on "W" Nordyne/Intertherm M3RL080A. Have a customer with a ICP high efficiency furnace, throwing a 4 flashing light code, limit switch open It is a bad circuit board either not sending 24v to the limit circuit, OR it does not recognize the 24v returning back from the limits

Limit circuit open or External Load on "W" Nordyne/Intertherm M3RL080A. Even raised the limit temp up by 10 degrees didnt want too but was told to by tech support Here is what I have done so far (most as part of general service): Changed 2 x limit switch Changed Pressure switch Changed ignitor Changed flame sensor Changed board Anyone any ideas with these furnaces as to why it would still throw this code after this?