PROALL P Series, Service Manual, Page: 38 / 118

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1. There may be a problem with the RPM sensor. The
control system requires feedback from the RPM
sensor to maintain the desired aux speed. Check the
sensor gap or replace the RPM encoder. If manual
operation is desired, then the operator can over-ride
the aux control valve to “full” or 100% open. More
product will be consumed if the desired ratio is
smaller.
2. The coil on the aux hydraulic valve may be faulty or
the valve may be sticking reducing the required oil
flow rate to the motor. If the problem is a faulty
coil, the operator can manually over-ride the valve
and set the desired aux ratio on the mixer control
screen using the “Actual” value shown in the rpm
field. This is a temporary solution and should be
done with a fixed belt speed.
Water PID alarm. This alarm indicates
that the desired water flow rate cannot
be achieved when the control system is
in automatic water mode. This alarm
will shut off the mixing operation. The
operator must acknowledge the alarm
by pressing the belt button on the
keypad. The mixing operation may be
continued by performing the following
operations.
If there is a problem with the automatic mode, the
water control can be placed in manual water mode (see
Mixer Control). Water control is in manual mode when
the yellow light flashes on the Water ON button on the
keypad (#17). Manual mode allows the operator to
control the water pump or water valve manually using
the Water to Cement (W/C) ratio dial on the HOME
PAGE. The W/C ratio is no longer a real time value. It is
simply a percentage out of 100. If the problem is with
the water valve controls, then the operator can
manually over-ride the hydraulic valve and control the
water flow using the manual water control valve at the
back of the mixer. Typical causes for this alarm are:
1. The hydraulic system has not had sufficient time to
become warm before high water flows can be
achieved. Reduce water flow requirement until
operating temperature is achieved, typically above
90°F/32.2°C. Water flow required is reduced by
lowering the belt speed.
2. The engine RPM is not at high idle. If the pump is not
turning fast enough the oil flow rate required for the
water pump and the belt circuit may not be
achievable. Increase engine RPM.
3. There may be a problem with the water flow meter.
The control system requires feedback from the water
flow meter to maintain the desired water flow rate.
Check the water flow on the display to see if a
reading is showing.
4. The coil on the water hydraulic valve may be faulty
or the valve may be sticking reducing the required oil
flow rate to the water pump motor.
The charge pressure feeding the main
pumps is low. Check charge pump
operation ensuring the charge pump
suction valve is open. If oil is cold,
allow the system to warm up before
running belt or mix auger at high speed.
The hydraulic oil temperature is
reaching a critical limit and should be
monitored. Check to ensure cooler is
running and oil levels are correct.
The hydraulic oil level is at a critically
low level. Verify tank level on sight
glass to ensure the sensor is working
properly.
The hydraulic pressure filter for the belt
circuit is in bypass. Change the filter
element to see if alarm goes away.
The hydraulic pressure filter for the
auger circuit is in bypass. Change the
filter element to see if alarm goes away.