PH-20/PHX-20 Manual
34
TROUBLESHOOTING
Metering Pump Line (cont’d)
IF THE DIRECTIONAL LIGHT IS OFF PROCEED BELOW
BEFORE TROUBLESHOOTING THE REVERSING SWITCH PLATE MUST BE MOVED
AWAY FROM THE SWITCH.
a) Bleed the down the chemical pressures.
b) Ensure Pump Switch [Y, page 12] is OFF.
c) Turn on the motor [X, page 12].
d) Go to the Directional Valve and locate the Actuation Coils. Located in the middle of
each coil is small round tab that can be pushed in to manually shift the spool to
move the pumps. If the Reversing bushing is all the way to the bottom push in on
the right side coil. If it’s all the way to the top push in on the left side coil.
TURN OFF ALL ELECTRICAL POWER TO THE MACHINE.
Using an ohm meter check the reversing switch
TROUBLESHOOTING
Metering Pump Line (cont’d)
4. Safety Pressure Switch
Each Metering Pump has a Safety Pressure Switch [I, L, page 9] set to 2,200 psi. for
#123 pumps, 3,200 psi for #61 pumps. When the material system reaches this
pressure, the Safety Pressure Switch will remove power from the Directional Valve
and Direction Indicator Lights [Y, page 11]. Lack of Direction Indicator Lights along
with high pressure indicated on one or both of the material Pressure Gauges [H, K] is
a indication of a over-pressure condition. The Safety Pressure Switches are a
momentary design; when the pressure bleeds off the Metering Pump Line will resume
normal operation. However, the cause of the over-pressure should be determined and
corrected. The three most common causes are:
a) Cavitation of the Metering Pump on the low pressure side
b) Causing high pressure on the opposite side.
c) A restriction in the Spray Gun on the high pressure
side.
5. Pressure/Material Imbalance
In summary troubleshooting this problem requires the applicator
to:
a) Know what the NORMAL spray pressures are for the application in progress.
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