PROALL P Series, Service Manual, Page: 25 / 118

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then there is blockage or stuck downstream valve/function
(cement, color or aux).

In the Mixer Control screen activate the last downstream
function in unload mode first. For example, if the mixer has
a color feeder as the last function in the series circuit then
run the color feeder by itself first. Run each function
individually checking to see if it turns and the pressure has
dropped below 3600psi.

During this sequential process you will likely get to a
function when in unload mode that causes the pump to go
to compensator pressure of 3600psi.

There are a couple reasons for a function to cause the pump
to compensate at high pressure. One of those reasons is a
stuck hydraulic valve. You can try and manually override
the valve to free it up. If this does not work, you can try and
replace the valve with another downstream function and
see if the issue moves. If the issue moves or goes away,
then the valve needs to be replaced.

If replacing and/or manually overriding the valve does not
work, then there is something mechanically
blocking/jamming the function from turning.
5.4.4 CEMENT

If the Commander system is showing an auto cement alarm,
then this is an indication that the output speed is not
matching the set-point speed.

Check to see if the actual RPM is showing in Digital
Readouts and that it matches the set-point RPM when
mixing (see the CANBUS Speed Sensor section for more
detailed troubleshooting).

Confirm that the speed set-point is above about 10RPM. If
the mix design entered has a very low content of cement
then the output speed required may be very low, which
may cause control issues. If possible, increase the belt
speed % to increase the cement setpoint.

In the Electrical Diagnostics screen select the cement
current diagnostic and check and see if the current
increases when the cement is activated. Also, confirm that
the cement speed solenoid indicator light is on.

If the speed sensor is working properly and electrical
current is going to the cement valve coil the next step is to
check the belt pressure in the Diagnostics screen. Run the
cement in cement unload mode and watch the belt
pressure. If the pressure is under 2000psi and the cement is
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