TCA200 Rev171031
15
Running Away From Water, Low Water, or No Supply Water
There are situations during pump operations when there may be low or no supply
water. This can be due to an empty water tank, a problem on the intake line, air in the
pump, changing the water source, or an insufcient water supply.
The governor constantly monitors discharge pressure and compares it to the engine
RPM. It is programmed to limit RPM increases when conditions arise that fall outside
normal operating parameters.
Running Away From Water: If the discharge pressure starts dropping while
operating in pressure mode, the governor will increase the engine RPM and attempt to
maintain the selected pressure setting. If pressure drops and an increase in RPM does
not bring the pressure back up, the governor recognizes this as a running away from
water condition. When this condition occurs the governor will switch to the RPM limit
mode and limit the engine RPM accordingly.
RPM Limit Mode: When the RPM limit mode is in effect the PRESSURE LED
will stay on. To alert the operator the RPM LED and the RPM display ash, and the
message display ashes LO WATER. When the pressure comes back up, the RPM
limit mode is canceled and the governor switches back to normal operation in pressure
mode with the existing pressure setting.
In some cases the pressure may not come back up but remains at a level above
45 PSI. In the RPM limit mode the governor will behave like a manual throttle and
the operator can raise or lower the engine RPM by pressing INC/DEC buttons. In this
mode the pressure setting will not change, the PRESET button is disabled, and if the
engine is set to idle using the IDLE button, the governor comes out of RPM Limit
Mode and cancels the pressure setting.
Low Water Cycle: If the discharge pressure is below 45 PSI but stays above 15
PSI the governor goes into a low water cycle. It sets the engine at 1100 RPM, if the
pressure does not rise above 45 PSI in 7 seconds the governor sets the engine at idle
RPM. The governor repeats this low water cycle as long as the discharge pressure is
between 15 and 45 PSI. When the pressure rises above 45 PSI the governor resumes
normal operation. (The values for RPM and PSI in the low water cycle are programmable
and may vary for some engine/pump combinations.)
No Supply Water: If the discharge pressure is below 15 PSI the engine RPM is
set to idle. If within 3 minutes the discharge pressure rises above 15 PSI the governor
enters the low water cycle. If the discharge pressure does not rises above 15 PSI within
3 minutes the governor stays at engine idle and cancels the pressure setting. To restart
pumping the operator will have to take action (press PRESET and/or INC/DEC buttons
to select pressure setting).
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