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Truckmount Troubleshooting
Identify and solve technical issues
Quickly diagnose and resolve issues with your Prochem or Sapphire truckmount. Select your model in the pull-down menu to access the relevant troubleshooting guide.
Legend GT Troubleshooting Tips
Main circuit breaker on the control panel has been tripped.
After inspecting the unit to determine the cause of the tripped breaker, press the reset button.
Loose or corroded battery connections.
Clean, tighten or replace the battery terminals.
Dead battery.
Recharge or replace battery
Defective ignition switch.
Test ignition switch for power going into the switch. If there is power going in, but none coming out, replace the switch.
Defective starter motor.
Test the starter motor. Replace if necessary.
Vacuum pump seized.
Refer to the vacuum pump manufacturer service and repair manual.
Waste tank is full.
Empty the waste tank.
Defective fuel pump.
Replace the fuel pump.
Loose or broken wires leading to the waste tank float switch.
Repair or replace any broken electrical connections.
Defective float switch inside waste tank.
Check switch for proper operation. Replace if necessary.
Oil pressure switch (located on engine), fuel shut-off solenoid (located on engine).
Test these components. If any are defective, replace. Refer to the engine Operation and Maintenance Manual.
Engine is malfunctioning.
Refer to the engine Operation and Maintenance Manual.
Engine is out of gasoline.
Check the fuel tank.
Waste tank is full.
Empty waste tank.
Main circuit breaker on the control panel has been tripped.
After inspecting the unit to determine the cause of the tripped breaker, press the reset button.
Oil pressure switch on engine has shut down due to insufficient oil pressure.
Refer to engine Operation and Maintenance Manual. DO NOT restart the engine until the cause is determined and corrected.
Defective fuel pump.
Replace fuel pump.
Defective float switch inside waste tank.
Check switch for proper operation. Replace if necessary.
No ignition in the engine or the engine is malfunctioning.
Refer to engine Operation and Maintenance Manual.
Vacuum gauge is giving an improper reading.
Examine the tubing between the vacuum relief valve and the vacuum gauge and remove any blockage.
Plugged vacuum hose or vacuum plumbing between vacuum inlet and strainer basket.
Unplug vacuum hose or inlet plumbing.
Vacuum relief valve requires adjustment or has a vacuum leak due to damaged diaphragm.
Re-adjust the vacuum relief valve. If the vacuum does not increase, remove and inspect the relief valve diaphragm. If damaged, replace.
Vacuum hose is damaged, causing a suction leak.
Inspect hose, repair or replace.
Waste tank gaskets not sealing properly, not positioned properly.
Inspect the gasket. Repair seal or replace Re-position lid.
Waste tank filter or strainer basket is plugged.
Clean or replace filter. Clean strainer basket.
Loose vacuum pump drive belts.
Tighten the drive belts.
Waste tank drain valve is damaged or left open, causing a vacuum leak.
Drain the waste tank. Close drain valve, if open. Replace valve if defective.
Vacuum exhaust heat exchanger plugged.
Remove and clean.
Vacuum pump is worn out.
Replace the vacuum pump.
Vacuum relief valve requires adjustment.
Readjust vacuum relief valve to 13 in. Hg.
Improper throttle adjustment.
Adjust throttle to set desired vacuum pressure.
Water supply is turned off or the float valve is stuck or improperly adjusted.
Turn the water supply on or up. Check for kinks in the water supply hose. Examine the float or replace.
Water pump inlet supply line is plugged or drawing air.
Examine the water inlet filter inside the water box. Remove accumulated debris and replace if required. Check for suction leaks and loose clamps or fittings. Tighten any loose fittings or clamps. Replace any ruptured hose(s).
Improper engine speed.
Using a tachometer, check the engine speed. Full throttle engine speed is 3000 RPM. Idle engine speed is 1500 RPM.
Pressure regulator O-rings are dry and/or worn. See instructions on regulator.
Check O-rings. Lubricate and/or replace as needed, using O-ring lubricant.
Pressure regulator is dirty, stuck open, or improperly adjusted. See instructions on regulator.
Clean or repair regulator. Adjust to working pressure. Lubricate O-rings, using O-ring lubricant.
Low pump volume. (Measure the amount of water being returned to the water box from the pressure regulator. It should fill a gallon container about every 17.6 seconds).
Examine the check valves, plunger cups, and cylinder head on the water pump. Repair, whenever required (refer to the water pump service manual).
Defective water pressure gauge.
Replace gauge.
Orifice (spray nozzle) in the cleaning tool is worn, defective or wrong size.
Replace nozzle or change nozzle size.
Debris clogging water lines or water inlet disconnect.
Clean or replace as needed.
Belts loose or broken.
Re-tension or replace as needed.
Loss of pump prime.
Manually prime water pump.
Temperature balance orifice missing.
Replace orifice.
Plugged orifice and/or screen in the cleaning tool.
Unplug or replace orifice and/or screen.
Internal block between the inlet pressure regulator and the solution outlet manifold, or the solution screen is clogged.
Inspect all lines, remove accumulated debris which is blocking flow. Replace any defective hoses. Remove, inspect, and clean the solution screen. De-scale unit and install a water softener, if necessary.
Outlet check valve is plugged.
Examine the check valve, remove any debris.
Defective quick-connect on one or more of the high pressure hoses.
Replace defective quick-connects(s) on high pressure hoses(s).
Cleaning tool valve is malfunctioning.
Repair or replace valve.
Hose inner lining is constricted.
Remove restriction or replace hose.
Air leak in chemical supply line, priming valve or metering valve.
Check for air leaks. Replace faulty parts.
Water pump circuit breaker has been tripped.
Check the water pump circuit breaker on the control panel. Press the circuit breaker reset button.
Defective electrical connection in the console wiring or defective switch.
Examine switch, electrical connections, and wiring. Repair any defective connections. If there is power going to the switch but not going out, replace the defective switch.
Water pump has not been activated.
Turn water pump switch to on.
Defective water pump clutch.
If there is power in the switch, but not power at the clutch, replace the defective wire. If there is power at the clutch, replace the clutch.
Loose or broken water pump belts.
Tighten or replace belts.
External leak in chemical piping.
Tighten or replace fittings. Re-apply thread sealant where required.
Outlet check valve is full of debris or damaged, not allowing it to close properly.
Close the chemical valve on the instrument panel. If the flow meter does not indicate flow, remove debris or replace check valve, if necessary.
Chemical pump diaphragm is ruptured.
Close the chemical valve on the instrument panel. If the flow meter still indicates flow, replace the chemical pump diaphragm.
Internal leak in chemical valve causing continual flow through prime tube returning to container.
Tighten valve packing nut (see “General Service Adjustments). Replace valve, if necessary.
Chemical pump is improperly primed.
Refer to chemical pump priming instructions.
The strainer at the inlet end of the chemical inlet line is clogged.
Unclog the strainer. If damaged, replace.
Suction leak in the inlet line leading into the chemical pump.
Inspect inlet lines and flow meter for air leaks or damage.
Chemical pump check valve(s) is clogged.
Remove any debris from the chemical check valve(s). Replace chemical check valve(s) or seals, if necessary.
Chemical prime/on-off valve or chemical metering valve is defective.
Replace valve(s).
Chemical pump diaphragm is ruptured.
Disassemble the chemical pump and replace the damaged diaphragm.
Defective cylinder in the pressure pump.
Measure the pump volume. If the pump volume is less than normal, refer to “Loss of Solution Volume” in this section.
Orifice clogged.
Clean orifice.
Flow restriction caused by hard water scaling.
Descale unit, repair or replace damaged plumbing components as necessary. Install a water softener.
Not enough water flowing during normal operation.
Check jet size of tool.
No vacuum hose is connected.
Connect vacuum hose to vacuum inlet port.
Temperature relief valve on water box is stuck open.
Clean temperature relief valve and test. Replace if necessary.
Engine RPM is low.
Reset engine RPM.
Defective temperature gauge.
Test gauge and sensor. Replace failed component.
Temperature balance orifice missing.
Replace orifice.
Temperature control valve left open.
Close valve, check for leaks. Replace if leaking.
Water is dripping from the exhaust port due to condensation build-up.
NOTE: The heat exchanger will produce water condensation discharge at times during normal operation. Do not confuse this with a leak.
Heat exchanger is damaged from frozen water.
Inspect heat exchanger for leaks. Visually inspect for damage. Pressure check after removing the unit (maximum test pressure – 1500 PSI).
Defective waste pump float switch.
Replace float switch.
Broken diaphragm(s).
Replace diaphragm(s).
Weak battery.
Charge or replace battery if needed. Check charging station.
Pump-out circuit breaker on control panel has been tripped.
After inspecting waste pump to determine the cause of the tripped circuit breaker, press the reset button.
Inspect check valve for debris or damage.
Clean or replace if necessary. Ensure that check valves are seated correctly.