Hey guys please delete if I have asked this in the wrong section


I have a C&R diesel engine heater it worked great for a while now when I start it the error code F31 comes up on the screen.

Has anyone come across this?
There isn’t a F31 code in the manual I have


Any help would be greatly appreciated

Combustion air blower fault/ check lead to combustion motor for continuity

This was on a c&r dealer website I tried to upload it but I couldn’t,sorry