Gusmer H20/35 Troubleshooting Advice

We do our best to answer your product-related questions in an informative and easy-to-understand manner. Below are several frequently asked questions from our customers.

Frequently Asked Questions

  • Check the position of the relay. 
    • If the relay is in the down position, check the motor. 
    • If the relay is in the up position, check wiring.
  • Check wiring between the following components:
    • Motor junction box and CB4
    • Wires on fuses F1 and F2
    • RLY2 and main disconnect switch
  • Confirm wiring is correct and insulation is intact. 
  • Reset CB4 within the electrical enclosure.
  • Verify that all FTS connections are snug and that pins of connectors are clean. Unplug and replug FTS wires along length of hose, cleaning off any debris.
  • FTS should be installed close to end of hose in same environment as gun. Verify FTS installation. See Repair Fluid Temperature Sensor (FTS), in manual.
  • Feed pump pressure is too low. Adjust pressure to maintain 100 psi (0.7 MPa, 7 bar) minimum.
  • Fluid is too thick. Consult your material supplier for the recommended fluid temperature to maintain a viscosity of 250-1500 centipoise
  1. Check the functionality of each proximity switch.
    • Remove the front cover.
    • With the motor powered off, confirm that the indicating light son the body of each proximity switch turns on when a metallic item, such as the shaft of a screwdriver, is placed on the face of each switch.
    • If the indicating lights turn on, the proximity switches and switch wiring are likely operating correctly; proceed to step 2. If the indicating lights do not turn on, proceed to step 6.
  2. Confirm the proximity switches, switch bracket, and switching plate are firmly mounted and not damaged.
  3. Check distance between the proximity switches and the switching plate.
    • Park the pump.
    • Confirm that the proximity switch nearest the A-side of the pump is backed out 0.5 to 1.5 turns from being in contact with the switching plate.
    • Disconnect the cable from the proximity switch nearest the B-side of the pump. Operate the pump until the switching plate is located above the B-side proximity switch, then turn off the motor/pump. 
    • Confirm that the proximity switch nearest the B-side of the pump is backed out 0.5 to 1.5 turns from being in contact with the switching plate. 
    • Reconnect the cable to the B-side proximity switch.
  4. Check functionality of the directional valve.
    • Inspect wiring inside the cover of the directional valve. See Electrical Schematics, in manual.
    • During operation, the direction indicator lights on the directional valve body should switch on based on the valve that is open.
    • Turn on the motor and stall the pumps at the lowest pressure setting (compensator knob turned fully counter-clockwise). The pump will travel in either the A or B direction until the pressure setting is reached.
    • Identify the solenoid that is operating by viewing the direction indicator lights on the cover of the directional valve. Measure voltage across the associated terminals to determine if proper voltage is reaching the valve (approximately 200 to 240 VAC). See Electrical Schematics, in manual, and the Pump Position Table to identify the proper terminals to measure across.
    • Trigger each proximity switch with the shaft of a screwdriver, confirming each solenoid within the directional valve operations as described in the Pump Position Table.
    • If one or both sides are not operating properly, according to the Pump Position Table, first reconfirm wiring to directional valve per Electrical Schematics, in manual, then replace directional valve.
  5. If you have determined that the cause is none of the previous possible causes, check for a loose piston packing retaining bolt. This causes the piston to contact the inner face of the pump inlet flange before the switching plate activates the proximity switch. Shut down the unit and disassemble the appropriate pump for repair.
  6. Following step one, if the proximity switch indicating lights do not light:
    • Check for loose or faulty proximity switch cable or connections. Confirm the connections to the proximity switches are tight and internally free from oil and other contaminates.
    • Swap the cables to the proximity switches to see if the problem follows the switch or is in the cable. Replace either the failed switch or the cable.
  • The Gusmer proportioner requires standard, 2-component heated hoses with thermocouple.
  • Check FTS. See Repair Fluid Temperature Sensor (FTS), in manual.
  • FTS should be installed close to end of hose in same environment as gun. Verify FTS installation. See Repair Fluid Temperature Sensor (FTS), in manual.
  • Check connections. Repair as necessary.
  • Reset breakers CB3 and CB5. See Electrical Enclosure, in manual.
  • Turn on hose heat zone.
  • Check setpoints. Increase if necessary.
  • Increase A and B setpoints. Hose is designed to maintain temperature, not to increase it.
  • Increase A and B setpoints to increase fluid temperature and keep it steady.
  • Use smaller mix chamber. Decrease pressure.
  • Wait for hose to heat to correct temperature before spraying.
  • Verify line voltage. Low line voltage significantly reduces power available to the hose heat system, affecting longer hose lengths.
  • Relocate hoses to a warmer area or recirculate heated fluid through the hose.
  • Check FTS. See Repair Fluid Temperature Sensor (FTS), in manual.
  • Verify line voltage. Low line voltage significantly reduces power available to the hose heat system, affecting longer hose lengths.
  • Match tap setting on transformer to hose length being used.
  • Check primary heater for either a thermocouple problem or a failed element attached to thermocouple. See Electrical Schematics, in manual.
  • Verify that all FTS connections are snug and that pins of connectors are clean. Unplug and replug thermocouple wires, cleaning off any debris.
  • Cover hoses or move to a location with a lower ambient temperature.
  • Match tap setting on transformer to hose length being used.
  • Check electric motor rotation. Both motor and hydraulic pump must rotate counterclockwise when viewed from the shaft end. If rotation is incorrect, reverse leads L1 and L2. See Connect Power, in manual.
  • Check dipstick to ensure that hydraulic reservoir is properly filled. See Preventative Maintenance Schedule, in manual.
  • Check that inlet fitting is fully tight to ensure no air is leaking into the pump inlet.
  • To prime pump, run unit at lowest pressure setting and slowly increase pressure. In some cases, it may be necessary to remove motor cover and drive belt to allow for manual (counterclockwise) rotation of hydraulic pump. Turn fan pulley by hand. Verify oil flow by removing oil filter to see flow into filter manifold. Reinstall oil filter. Do not operate until without a properly installed oil filter.
  • If noise continues longer than 30 seconds, shut off motor by turning the motor power switch (c36) to OFF position. Check that the inlet fittings are tight and that the pump has not lost its prime.
  • Ensure that the reservoir is properly serviced. 
  • Improve ventilation to allow more efficient heat dissipation.
  • Motor must operate counterclockwise from pulley end.
  • Verify motor is wired properly according to schematic found inside motor junction box.
  • Check drive belt condition. 
  • Replace if broken.
  • Increase A and B setpoints. Hose designed to maintain temperature, not increase temperature.
  • Check setpoint. Increase if necessary to maintain heat.
  • Use smaller mix chamber. Decrease pressure.
  • Install FTS. Refer to your heated hose manual for instructions.
  • Check connections. Repair as necessary.
  • Relocate hoses to a warmer area or increase A and B setpoints.
  • Match tap setting on transformer to hose length being used. 
  • System is limited to 310 feet (94.5 m).
  • Clean the gun. See your gun manual.
  • Increase fluid supply to proportioning pump:
    • Use 2:1 or greater supply pump
    • Use minimum 3/4 in. (19 mm) ID supply hose, as short as practical
  • Fluid is too thick. Consult your material supplier for the recommended fluid temperature to maintain a viscosity of 250-1500 centipoise
  • Clean inlet strainer screen.
  • Worn pump inlet valve ball/seat or gasket. Replace pump.
  • Remove return line and determine if flow is present while in SPRAY mode.
  • Check if heater and pressure relief valves are plugged. Clear.
  • Replace rupture disk with a new one; do not replace with a pipe plug.
  • Check feed pump pressure and adjust to 100 psi (0.7 MPa, 7 bar) minimum.
  • Check for leaks in the system. 
  • If there are no leaks, set the pressure imbalance dial higher.
  • Determine cause of pressure imbalance. Correct issue. See Pressure/Material Imbalance, in manual.
  • Turn the pressure balance switch to the OFF/RESET position.
  • Check thermocouple connections and wire for damage. Replace if necessary.
  • Loosen the ferrule nut.
  • Push in the thermocouple wire so that the tip contacts the heater element.
  • Hold the thermocouple tip against the heater element while tightening the ferrule nut 1/4 turn past tight.
  • See Replace Heater Element, in manual.
  • If there is a signal failure from the thermocouple, the thermocouple controller will prevent the heaters from operating.
  • If this occurs, replace the thermocouple. See Replace Thermocouple, in manual.
  • Check for a resistance of 4-6 ohms between purple and red wires on the temperature controller. There should be a reading of infinity between the ground wire and purple wire.
  • Turn on heat zones.
  • Check CB1 for A-side heater and CB2 for B-side heater.
  • While red temperature controller light is on, measure voltage (5 VDC) between T3 and T4 on SSR.
  • While red temperature controller light is on, measure line voltage (230 V) between T2 of the heater control relay and T2 of the SSR.
  • If testing fails to determine the problem, replace the SSR.
  • The two primary heater controllers are interchangeable.
  • To test for a faulty controller, turn off the main power disconnect and disconnect incoming power.
  • Replace the suspect controller and retest.
  • If this occurs, replace the thermocouple. See Replace Thermocouple, in manual.
  • Check for a resistance of 4-6 ohms between purple and red wires on the temperature controller.
  • There should be a reading of infinity between the ground wire and purple wire.
  • Thermocouple must make contact with the heater cartridge.
  • Heater cartridge must be functioning properly.
  • Lack of either of these conditions may cause erratic temperature control and possible overheating. To check thermocouple position, see Replace Thermocouple, in manual.
  • See Replace Primary Heater, in manual.
  • Observe gauges to determine which pump is losing pressure.
  • Determine where the pump has stalled by checking the directional indicator light (c35).
  • Repair the valve. See your pump manual.
  • Open fluid hose to clear obstruction or use hose with larger ID.
  • Check feed pump pressure and adjust to 100 psi (0.7 MPa, 7 bar) minimum.

NOTE: For diagnostic purposes, it is possible to manually override the directional valve by using a small screwdriver to depress the button in the center of either directional valve end cap. Depressing the button in the right end cap should cause the pump to travel to the right. Depressing the left button should cause the pump to travel to the left.

  1. Check the functionality of each proximity switch.
    • Remove the front cover.
    • With the motor powered off, confirm that the indicating light son the body of each proximity switch turns on when a metallic item, such as the shaft of a screwdriver, is placed on the face of each switch.
    • If the indicating lights turn on, the proximity switches and switch wiring are likely operating correctly; proceed to step 2. If the indicating lights do not turn on, proceed to step 6.
  2. Confirm the proximity switches, switch bracket, and switching plate are firmly mounted and not damaged.
  3. Check distance between the proximity switches and the switching plate.
    • Park the pump.
    • Confirm that the proximity switch nearest the A-side of the pump is backed out 0.5 to 1.5 turns from being in contact with the switching plate.
    • Disconnect the cable from the proximity switch nearest the B-side of the pump. Operate the pump until the switching plate is located above the B-side proximity switch, then turn off the motor/pump. 
    • Confirm that the proximity switch nearest the B-side of the pump is backed out 0.5 to 1.5 turns from being in contact with the switching plate. 
    • Reconnect the cable to the B-side proximity switch.
  4. Check functionality of the directional valve.
    • Inspect wiring inside the cover of the directional valve. See Electrical Schematics, in manual.
    • During operation, the direction indicator lights on the directional valve body should switch on based on the valve that is open.
    • Turn on the motor and stall the pumps at the lowest pressure setting (compensator knob turned fully counter-clockwise). The pump will travel in either the A or B direction until the pressure setting is reached.
    • Identify the solenoid that is operating by viewing the direction indicator lights on the cover of the directional valve. Measure voltage across the associated terminals to determine if proper voltage is reaching the valve (approximately 200 to 240 VAC). See Electrical Schematics, in manual, and the Pump Position Table to identify the proper terminals to measure across.
    • Trigger each proximity switch with the shaft of a screwdriver, confirming each solenoid within the directional valve operations as described in the Pump Position Table.
    • If one or both sides are not operating properly, according to the Pump Position Table, first reconfirm wiring to directional valve per Electrical Schematics, in manual, then replace directional valve.
  5. If you have determined that the cause is none of the previous possible causes, check for a loose piston packing retaining bolt. This causes the piston to contact the inner face of the pump inlet flange before the switching plate activates the proximity switch. Shut down the unit and disassemble the appropriate pump for repair.
  6. Following step one, if the proximity switch indicating lights do not light:
    • Check for loose or faulty proximity switch cable or connections. Confirm the connections to the proximity switches are tight and internally free from oil and other contaminates.
    • Swap the cables to the proximity switches to see if the problem follows the switch or is in the cable. Replace either the failed switch or the cable.
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