Generac Power Systems MAC 750F Owner's Manual page 26

Troubleshooting
Message
Heater Shutdown due to temperature, pressure
or level out of range
Fuel Over temp.
22
High hydraulic temperature
Low hydraulic pressure
Low hydraulic level
Fuel temperature >= 140° F
Open heat circuit solenoid
1.
Increase scroll fan RPM to max RPM via fan circuit sole-
2.
noid and drop engine to idle
Monitor fuel temperature for five minutes
3.
Fuel temperature is still >= 140° F
Open heat circuit solenoid
1.
Drop engine to idle
2.
Unit will shut down after five minutes
3.
Cause
Owner's Manual for Flameless Air Heater