you're welcome
can i presume you found the problem?
blown fuse?

Thank you swoop. I can see from the other discdussions that your are a professional at your trade. jc

f4 is not a normal status (error) code on these GE systems
error codes are generally displayed by a -xx (traction) or -**** (pump) code format. No letters

If you are getting a f4 i would check the fuses in the rear panel and make sure none of them are blown.
FU4 on the main control panel is the main 350A or 500A (depending on what controller it has in it) fuse connected to the line contactor circuit buss.
Check that and make sure it's not blown or badly connected.
check for burning etc.