Service Home Standard Coolant - Troubleshooting Guide - CHC
Last updated: 11/22/2024

Standard Coolant - Troubleshooting Guide - CHC

Download and fillout the coolant pump Inspection Report Checklist below before replacing any parts.

Coolant pump Inspection Report Checklist

Introduction

Introduction

The following service video shows how to troubleshoot a standard flood coolant pump

NOTE: This video is for reference only and does not replace the written procedure.

This troubleshooting guide applies to both 1-Phase and 3-Phase pumps.

In this image, the following components are shown.

  1. Coolant Pump Motor
  2. Coolant Outlet
  3. Pump Body
  4. Impeller Cap
  5. Impeller

NOTE: For troubleshooting information on the coolant float sensor, refer to the Coolant Level Float Sensor - Troubleshooting Guide for more information. 

NOTE: Coolant Pumps with  PN: 30-14261 (1HP, 3-Phase without VFD) will follow the same installation process for non-VFD applications across all machines, with the exception of VF's VP-5, VM's, ST/DS, and UMC's.

ID0013 Coolant Pump Inspection Report Checklist requires the pump's serial number to be completed. 

The serial number can be found on the side of the pump [1] in the box labeled serial number [2]

Symptom Table

Symptom Possible Cause Corrective Action
Noisy pump or cavitation Poor Coolant flow through enclosure Remove chip buildup.
Low Coolant Level Fill coolant tank.
Impeller contamination, or impeller damage Inspect impeller for damage or debris. Clean impeller or order kit 93-2609 to replace impeller. Follow Impeller Replacement Procedure to replace. 
Motor bearing failure. Rotate the shaft by hand
Low coolant flow. Poor Coolant flow through enclosure Remove chip buildup.
Low coolant level in coolant tank Fill coolant tank.
Impeller contamination, or impeller damage Clean Impeller
Filter or pump intake blockage. Clean filter, check pump intake for blockage.
Pump intake or coolant output hose blockage Remove coolant check-valve and coolant output hose blockage.
Coolant nozzle blockage Remove blockage from coolant nozzles
No coolant flow and coolant circuit breaker did not trip. Setting 32 COOLANT OVERRIDE is set to IGNORE. Set Setting 32 COOLANT OVERRIDE to NORMAL.
The overheat jumper at the I/O PCB is missing. Make sure the overheat jumper for the coolant pump is installed on the I/O PCB.
Coolant pump motor does not receive voltage. See the No Voltage at the Pump Motor section below.
Incorrect power phasing - pump motor is running backward. Correct phasing
No coolant flow and the coolant circuit breaker tripped. Coolant pump motor short to ground. Measure coolant pump motor resistance to ground.
The coolant level sensor displays an incorrect coolant level. The sensor is damaged, or the float cannot move. Check all of the wires and clear chips blocking the float.
The cable is unplugged or damaged. Make sure that the cable is securely connected and is not damaged.

Poor coolant flow through enclosure

Remove all chips from the the auger trough [1], and the coolant return drain [2].

Remove chips from the coolant tank. Excessive chips in the coolant tank reduce the amount of coolant the tank can store. Watch the video Machine Tool Coolant - Cleaning Your Tank - Video.

Fill the coolant tank. Watch the video Standard Coolant – Simplified - Filling your Tank … and More.

Make sure the coolant level sensor operates correctly.

Coolant Pump Impeller Damage/Contamination

Remove the impeller cap [1] from the bottom of the pump. Remove the screw that connects the impeller [2] to the shaft. Steel impellers have left-hand threads [3].

Carefully remove and clean the impeller [2]. Check for wear, damage, or cracking of the impeller [2].

If the impeller is damaged or cracked, order a replacement impeller, service part 93-2609. Follow Impeller Replacement Procedure to replace. 

Rotate the coolant pump shaft by hand. If the shaft does not turn freely, the motor bearings are damaged.

Install the impeller [2]. Rotate the coolant pump shaft by hand, and make sure the impeller does not rub on the pump body [4]. If the impeller rubs against the pump body, install shims between the impeller [2] and the coolant pump shaft. Install the impeller cap [1]. If the impeller [2] rubs against the impeller cap [1], remove one shim at a time until it does not rub.

There are several filters that keep chips out of the coolant pump. Refer to Section 3 for filter maintenance information.

Filter or pump blockage

Clean or replace the filter element. Check the area around the coolant pump intake for chips.

  1. Auxiliary Filter - The bag filters in Auxiliary Filter tanks need to be cleaned or replaced. The Auxiliary Filter is an option. Your machine might not have this option.
  2. Standard Filter - Standard Filters need to be cleaned.

Disconnect both ends of the coolant hoses. Remove any kinks. In the opposite direction of the coolant flow, blow air through the hoses to remove any chips. If you find chips in the hoses, check the coolant nozzles and washdown hoses for chip buildup. Connect the coolant hoses.

Remove chips from the basket filter in the coolant tank. For maintenance instructions, refer to the Coolant Tank ‑ Maintenance procedure.

Check valve blockage

Remove the coolant check-valve. Check it for blockage [1]. Make sure the trap door opens and closes freely. If the trap door does not close, coolant flows back into the tank. This delays the flow of coolant by a few seconds.

Disconnect both ends of the coolant hoses. Remove any kinks. In the opposite direction of the coolant flow, blow air through the hoses to remove any chips. If you find chips in the hoses, check the coolant nozzles and washdown hoses for chip buildup. Connect the coolant hoses.

Coolant nozzle blockage

Remove and clean the coolant nozzles.

Cycle the pump power to flush the coolant lines.

Make sure the coolant tank is free of chips and contamination.

Defective pump

  1. Disconnect the pump cable from the machine.
  2. With a ohm-meter measure each leg tab to the ground tab.

     Note: The ground tab has a bent. The example shown is a 3-phase pump with 4 tabs (L1, L2, L3 + Ground), single phase pumps have 3 tabs (L1, L2 + Ground).

    • If all the legs test open (O.L) to the ground tab then the pump and cable do not have a short circuit, see the next section.
    • If the motor cable leads [3] indicate a short, remove the motor cable cover and disconnect the cable from the motor.
  3. Measure the motor cable leads [5] to ground [6] terminal screw or chassis. If any lead tests short, the pump is at fault. If none of the leads [5] test short, the cable is at fault.
  4. If all the leads test OK, check the coolant pump for binding that could cause an over amperage condition.

No voltage at pump motor

  1. First inspect the pump motor for a short circuit see section Defective Pump.
  2. Make sure the coolant pump cable is connected to the machine.

     Important: Do not disconnect the coolant pump from the machine, doing this test without a load will give you false readings.

  3. Remove the pump motor cover and locate the white, black, red wires for 3-phase motor or white and black for a single-phase.
  4. Verify that coolant circuit breaker is set to on and setting 32 COOLANT OVERRIDE is set to NORMAL.
  5. Press the [COOLANT] button to turn on the coolant pump.
  6. Measure the voltage at the motor from lead to lead [1]. The reading must be 240 VAC. The motor shown is a 3-phase motor.
    • If you read 240 VAC, the coolant pump motor is damaged.
    • If you do not read 240 VAC, check at the I/O PCB coolant output. If there is still no voltage check the 240 VAC source from the PSUP PCB to I/O PCB.

Incorrect phasing

The power supply PCB has a phase detect with neon indicators on the top center portion of the board. Make sure that the electrical power is phased correctly:

  • Green Light: The incoming power is phased correctly.
  • Orange Light: The incoming power is incorrectly phased.
  • Both Lights: A phase is missing (there is a loose cable in the system).

If the electrical power is phased incorrectly:

Set the main circuit breaker to the OFF position.

Lock the main circuit breaker. Use an approved lock with an approved safety tag.

Swap the #74 and #75 incoming power cables at the main transformer.

Malfunctioning Sensor

In the first image, you can see the location of the coolant level sensor on the coolant tank.

Corrective Action:

If your coolant level sensor does not display the correct level on the screen, look in the coolant tank to make sure a chip build-up does not block the float from moving freely.

Make sure the coolant level sensor operates correctly:

  • Press [MEMORY]. The upper-right corner of the screen will show the coolant level.
  • Remove the level sensor from the tank and move the float to the maximum travel at both ends. The coolant level indicator on the screen should move at a slow pace. It takes approximately (1) minute to move from empty [2] to full [1] on the screen, but it starts to move immediately.
  • If the coolant level sensor does not operate correctly, unplug the coolant level sensor from the machine. Remove the cover to access the wires of the variable resistor.
  • Measure the resistance across the white and black wires [3/4] when the float is up [5] and when it is down [6]. The resistance should be approximately 371 Ohms when the float is up and 286 Ohms when it is down.
  • Make sure that the coolant level sensor RJ12 cable [2] or M12 cable [1] is securely connected, and is not damaged.
  • If the coolant level sensor continues to read incorrectly, and you have completed the troubleshooting instructions, replace the sensor.

Electrical Diagram