PMC PH Series - Metering Pump Line

PH-20/PHX-20 Manual
33
TROUBLESHOOTING
Metering Pump Line
Follow the recommended procedure in the indicated order to solve the problem and
avoid unnecessary repairs. Make sure all Switches are in the correct position and
Indicator Lights ON before determining the existence of a fault.
PROBLEM
Metering pumps do not change direction and the pressures on both of chemical
gauges are lower than normal.
SOLUTIONS
1. The top of the hydraulic piston shaft actuates a reversing switch at the end
of the stroke. The reversing switch in turn actuates the appropriate Directional
Valve Solenoid.
Failure to make contact with the reversing Switch may be caused by:
 Deformation of the Reversing bushing or a bent or loose reversing switch
mounting plate.
 Foreign material preventing the Reversing bushing from contacting the Switch.
If this is not the problem go to the next step
2. Passing of the Reversing bushing beyond the switch may be caused by:
 Failure of the Switch and related components on the side of the over-run.
 Failure of a component of the Direction Valve.
 Mounting Plate is bent or is out of adjustment.
3. Failure of the reversing switch or reversing valve coil
 If the pump directional indicator light is on check the reversing valve coil, each
coil should read approximately 19 ohms.
 If the pump directional indicator light is off and there is no hydraulic pressure
check for a defective reversing switch.