Service Home Coolant Refill Option - Troubleshooting Guide - TG0055

Coolant Refill Option - Troubleshooting Guide - TG0055

12.5 Coolant Refill - Troubleshooting

Last updated: 10/10/2025

Coolant Refill Option - Troubleshooting Guide

TG0055

Revision A - 02/2026

Exploded View

 WARNING: DO NOT ADD POWDERED/LIQUID COOLANT ADDITIVES TO THE COOLANT REFILL TANK.  THIS WILL DAMAGE THE SOLENOIDS AND VOID YOUR WARRANTY. ALL ADDITIVES MUST BE ADDED AND MIXED IN THE COOLANT TANK.

  1. COOLANT REFILL SOLENOID COIL CABLE
  2. WASHER 1 STEEL .120THK X1.562O
  3. STRN RLF PG13.5 .12"-.27" CD13BR-BK-N
  4. COOLANT REFILL OPTION CHASSIS
  5. FITG NPT1/8F NPT1/8F 90 BRASS
  6. NIPPLE HEX 1/8 NPTM X 3/8 SMOOTH
  7. NIPPLE 1/8 NPT X 2 BRASS
  8. SOLENOID AIR 2 P0RT 2 POS 1 COIL 1/8NPT
  9. NIPPLE 1/8 NPT X 1 HEX BRASS
  10. FITG NPT1/8M NPT1/8F NPT1/8F TEE BRASS
  11. VENTURI NOZZLE
  12. FITG REDUCER NPT1/4F NPT1/8M STR BRASS
  13. FBHCS 1/4-20 X 1/2 LOCTITE
  14. COOLANT REFILL OPTION COVER
  15. FITG COMP 3/8 X 1/4 MNPT 90 BR
  16. FITG NPT1/4F NPT1/4F STR BRASS
  17. NIPPLE 1/4 NPT X 3 1/2 BRASS
  18. FITG REDUCER NPT3/8M NPT1/8F BRASS
  19. STRN RLF PG13.5 .12"-.27" CD13BR-BK-N
  20. FITG NPT3/8 X DIA 1.000 BKHD BRASS
  21. FITG HOSE BARB-3/8 X NPT-3/8-M 90
  22. FITG BLKHD NPT3/8M/F X NPT3/4M X 2-1/2L
  23. FITG REDUCER NPT1-1/4M NPT3/4F NYLON
  24. GREASE STRAINER
  25. 5G TANK

Introduction

The image show the following components of the coolant refill system.

  1. Coolant concentrate tank
  2. Strainer
  3. Solenoid cable
  4. Filler hose
  5. Water solenoid cable
  6. Coolant concentrate solenoid cable

Symptom Table

Symptom Possible Cause Corrective Action
The coolant concentration in the coolant tank is incorrect. There is insufficient water pressure. Check the incoming water pressure.
The CRO is not calibrated. Calibrate the CRO.
The water supply or coolant concentrate solenoid does not receive voltage. Measure the voltage to the solenoids.
The water supply or coolant concentrate solenoid is contaminated and stays on. Clean the solenoids.
Thick concentrate, high viscosity. Install 1/2" nozzle on fill tube.
The CRO does not power on. The water supply or coolant concentrate solenoid does not receive voltage. Measure the voltage to the solenoids.
The coolant level sensor does not operate correctly. Troubleshoot the coolant level sensor.
The coolant tank overfills. The water supply or coolant concentrate solenoid is contaminated and stays on. Clean the solenoids.
The coolant level sensor does not operate correctly. Troubleshoot the coolant level sensor.
Weak output flow to coolant refill  Orifice is too small in venturi valve causing weak flow.  Order new venturi valve 20-6616 with a larger orifice.

Coolant Concentration and Ratios

Make sure that the water supply has the correct pressure. The water supply must have a pressure of 40-100 psi (2.8-6.9 bar) to produce the desired coolant concentration.

Make sure the water supply screen [1] is not clogged. Clean the screen [1] if it is clogged. Make sure the cone side of the screen points toward the water supply. Make sure that the hose [2] is straight and does not have kinks.

If an aftermarket water filter is installed, make sure it is not clogged.

To correct the batch of coolant that is in the coolant tank, refer to the video Machine Tool Coolant - Top Up High Concentration - Video

The system may need to be calibrated to produce the correct coolant concentration. For calibration instructions, refer to Coolant Refill - Calibration.

Electrical Fault

Disconnect the cable from the CRO unit to the coolant connector bracket on the side of the machine.

For this section, complete all voltage measurements with the CRO unit commanded ON. On the Coolant Refill display, press [F3] to Add 5 gallons of coolant. Press [F3] again when you are ready to stop the CRO.

 Note: Use the notch [A] in the connector as a reference to find the correct pin.

Measure the voltage to the water supply solenoid [1]: The voltage across pins 2 and 5 of the connector on the coolant connector bracket must measure 120 VAC.

Measure the voltage to the coolant concentrate solenoid [2]: The voltage across pins 1 and 4 of the connector on the coolant connector bracket pulses on and off for 0.25 seconds each time it activates. Set your multimeter to Min/Max.

If the voltage is correct at the connector bracket:

  1. Connect the cable from the CRO to the coolant connector bracket.
  2. Shut off the water source.
  3. Measure for the voltage at the solenoid connectors [1 and 2]. They must measure 120 VAC. If there is no voltage at the solenoids, the solenoid cable from the CRO to the coolant connector bracket is at fault.
  4. If the voltage to the solenoids is correct, clean the solenoids. Go to Section 5.

If there is no voltage at the coolant connector bracket: Go to the applicable link below to troubleshoot the I/O PCB.

Solenoid Malfunction

Clean the solenoid: Remove the red cap [1]. Push the solenoid coil assembly [2] down to compress the split spring [4] inside.

Remove the specification plate [3]. Remove the split spring [4] and valve subassembly [5] from the coil assembly [2].

Disassemble the valve subassembly [5]. Clean the parts with compressed air. Be sure to remove all debris from inside the valve. Apply a thin coat of high-grade silicone grease to the body gasket [6].

1/2" Nozzle on Fill Tube

Install the Fittings: Install a 1/2" nozzle to create backpressure in the system. This is needed for thick concentrate coolants.

  • 58-1122 FITG NPT3/8F NPT3/8F STR BRASS
  • 58-3048 FITG HOSE BARB1/2 NPT3/8M STR BRASS
  • 58-1842 HOSE 1/2 ID PU NYLON BRAIDED

Electrical Diagram