Midmark® Smart G-Vacuum Troubleshooting Chart

When working on Twin units, unplug parallel harness.

Display/Symptom

Cause

Check

Action

  N/A Front panel ON/OFF switch is OFF. Verify status of switch. Turn switch ON if in OFF position.
Circuit breaker tripped. Check disconnect box/main circuit breaker. Verify disconnect box/main circuit breaker is not tripped and in ON position.
Door limit switch disengaged. Verify when door limit switch engaged, motor turns on. Refer to: Door Limit Switch Ensure front panel fully engages door limit switch.
Remote Wall Switch
harness disconnected/loose.		 Verify Remote Wall Switch harness is fully seated on PCB J11 connection. Refer to: Remote Wall Switch or Wiring Diagram Secure connections or replace harness/Remote Wall Switch.
Separator Tank not draining. Possible clog in tank. Remove lid to see if tank is full. Remove clog.
Check valve is stuck closed. Refer to: Check Valve Repair/Replace check valve.
Check float harness is fully seated to electrical box connection. Check float PCB harness is fully seated on J6. Refer to: Wiring Diagram Repair/Replace harness.
PC Board malfunctioning. Verify LED's DS3 & DS4 are solid green. If green move to next step. If not, move to action. Check harness in J7 is seated. Refer to: Wiring Diagram Check power to board. Refer to: Check Fuse & Transformer
Verify LED's DS2 &/or DS9 are blinking on startup. If blinking move to next step. If not, move to action. Note: if DS9 light stays on after startup, there is an error in the system. Refer to: Check PC Board
Verify LED DS5 is solid green. If solid green then move to action. If not green then move to next step. Refer to: Check Variable Frequency Drive Test and Repair
Wire harness between VFD & line filter loose or broken. Check for loose or broken wires. Replace or Re-connect harness.
VFD not working properly. Check if error code is displayed on keypad. Refer to: VFD Error Code Chart
Look into side air vents of VFD and verify amber lights are on in VFD. If no lights on, refer to: Line Filter
Check Motor Enable Harness connection at J12 is secure. Secure/Replace harness.
Check loose or broken VFD harnesses. Refer to: Variable Frequency Drive or Wiring Diagram. Replace VFD or harnesses.
Pump is locked up. Feel for pump pulley drag or sticking. Refer to: Motor and Pump Test and Repair Contact Midmark Technical Service. 1-800-643-6275
Motor bad. Perform motor checks. Refer to: Motor and Pump Test and Repair Replace motor.

Display/Symptom

Cause

Check

Action

N/A

Motor not running.

Refer to: Motor not running or breaker keeps tripping

Refer to: Motor not running or breaker keeps tripping

Leaking or loose connection.

Check hoses and bulkhead fittings.

Secure/Replace hoses or bulkhead connections.

Check drain line check valve. Refer to: Check Valve

 Replace Check Valve.

Check Separator lid gasket.

Secure/Replace lid gasket.

Pump pulley not spinning freely.

Moisture in the pump.

P trap not installed properly.

Drain and release pump. Install P trap per instructions.

P trap drain system clogged.

Drain and release pump. Remove clog from P trap drain.

Leak in separator tank or drain check valve causing sudsing/spraying Check tank for air leaks. Repair or replace tank. Check tank drain check valve for leaks. Clean or replace valve.

N/A

Exhaust Hose Clogged

Remove exhaust hose to see if suction increases. If suction increased, check for clog.

Unclog or replace exhaust line

Pressure sensor not working properly.

Check pressure sensor. Refer to: Pressure Sensor

Replace pressure sensor.

Improper Belt Tension Tension pulley arm spring seized. Check if tension arm is seized by rotating the arm clockwise. Replace tension arm if cannot rotate smoothly.
Pulley belt worn or loosened. Check if belt is worn or loose. Replace pulley belt.

Display/Symptom

Cause

Check

Action

N/A

Ambient temperature too high.

Check equipment room temperature is within 40⁰ to 104⁰ F or 4⁰ to 37⁰ C

Refer to: Installation Manual site requirements

Pump is locked up.

Refer to: Motor and Pump Test and Repair

Contact Midmark Technical Service. 1-800-643-6275

Exhaust Hose Clogged

Remove exhaust hose to see if suction increases. If suction increases, check for clog.

Unclog or replace exhaust line

Motor not running.

Refer to: Motor not running or breaker keeps tripping

Refer to: Motor not running or breaker keeps tripping

VFD not working properly. Check if error code is displayed on keypad. Refer to: VFD Error Codes

Display/Symptom

Cause

Check

Action

N/A

Pressure sensor not working properly.

Check pressure sensor. Refer to: Pressure Sensor

Replace Pressure sensor.

Plumbing lines leaking.

Check office plumbing system for leaks.

Repair/Replace Plumbing Lines.

VRV malfunctioning.

Check VRV. Refer to: Vacuum Relief Valve

Adjust/Replace VRV.

Vacuum tank leaking. Check tank for holes, corrosion, or loose fittings. Repair/Replace tank or fittings.

Display/Symptom

Cause

Check

Action

Leaking Oil

Oil Reservoir is overfilled.

Check sight glass. Refer to: Motor and Pump Test and Repair

Drain Oil.

Pump is overheating.

Check ambient temperature in the room. Temperature should be 40⁰ to 104⁰ F or 4⁰ to 37⁰ C.

Contact a certified specialist to adjust temperature.

Check Clearance around unit. Allow 12 inches on the front and right side and allow 6 inches on the left side and back.

Adjust base unit to clearance specifications.

Check if fans are working. Refer to: Fan Test and Repair

Replace fans.

Minor Oil leak.

Minimal oil leakage may occur with no harm to the vacuum. Refer to the oil sight glass fill level requirements.

Monitor oil levels and fill as needed. Replace absorbent pad if required.