TM 9-2540-207-14&P
F4 - VENT AIR OVERHEAT
F4
The Ventilation Outlet temperature has exceeded a safe operating temperature of 345F (174C)
CHECK/POSSIBLE CAUSE
REF.
REPAIR
1
Check to see if fault occurs at
If fault occurs at Start Up go to step 7
Start Up
2
Check that all dampers in
Open all dampers fully
vehicle are open
Switch Heater to Low mode
3
Check for obstructions in front of
Remove obstructions
Heater Ventilation Outlet
Switch Heater to Low mode
4
Check all Ducting connections
vehicle
Install proper ducting correctly
TM
Switch heater to Low mode
2.2
2.3
2.7
5
Defective Heat Exchanger
5.4.1
Replace Heat Exchanger
Restart Heater
6
Heater did not properly Purge
2.5
Check all electrical connections and purge
3.5
Heater 3 times.
Restart heater
7
Defective Electronic
5.2.5
Replace Electronic Programmed Controller
Programmed Controller Board
Restart Heater
6-24
