Class1 107490 - UNI-Governor 107396 107269 software v 6 00 - Manual (Page 17)

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9 One or more switches are inoperative
This condition can be diagnosed with the self test IDLE INC IDLE INC IDLE INC IDLE INC
If you cannot enter the selftest, then one of the switches is shorted to ground and the governor must be
replaced. If you can enter the selftest, when the Message Center displays X X X 3 - 5 X X Each time
you press a switch a letter will be displayed in position 2, just before the 3.
i=IDLE
p=PRESET
u=INC (i is used for idle)
d=DEC
m=MODE
If there is a letter constantly displayed in position 2 then that switch is shorted and the governor should
be replaced. If one of the switches does not display it’s letter, then that is the switch that is bad and
again the governor should be replaced. If all of the switches display, then the governor is OK and one
of the functions is not set properly. PRESET would be the most likely one, however if the governor is
configured for the wrong engine type it could show up as the INC switch not seeming to operate.
note: The IDLE switch has a longer ‘debounce’ time than the rest. It must be held for a half second to
adequately be read. This is to prevent an accidental drop to idle when operating.
10 Fast Idle does not work
An RPM PRESET must be configured. Refer to section 8
12 VDC must be present on pin 2 (Throttle Ready)
12 VDC must
NOT be present on pin 10 (Pump Engaged)
12 VDC must be actively toggled at pin 3 once the governor has been powered on. If it is present at
governor power on, it will be ignored until it is turned off and then back on. Automatic Fast Idle activation
can cause this to occur.
11 Pressure Spikes
This can usually be traced to the GAIN setting. Set GAIN to a higher number if it is at 3 or below. The
other possibility is that the discharge is being closed too fast. The governor can maintain pressure
within 30 PSI as long as the change is not faster than 3 seconds. The governor can actually manage
faster changes than this, but the NFPA specification is 3-10 seconds. The governor operates best in
this range.
Snapping a nozzle closed could result in a pressure spike that the governor cannot handle fast enough
to protect other Firefighters.
12 Control does not return to Cab Throttle when finished pumping
This condition is the result of the PTO ON switch not being released. The governor drops out its internal
relay whenever the IDLE switch is pressed. (The governor has no Mode selected.) This can be tested
with a voltmeter at terminals 11 and 12 of the governor 12 pin connector. The PTO ON switch can be
tested at the engine ECM or with a Diagnostic Data Reader (DDR) with the appropriate software. The
governor is not necessarily used to control the PTO ON switch.
Consult your OEM for additional trouble shooting assistance in this area.