Standard Coolant - System - How it Works and Troubleshooting Guide

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How it Works

When you press COOLANT or use the M08 and M09 commands, the I/O PCB sends approximately 230 VAC to the coolant pump. The coolant pump activates and pumps coolant to the coolant nozzles and wash-down hoses. The coolant then returns to the coolant tank through the drain in the auger trough and the coolant return drain from the enclosure pan. The coolant continuously cycles through the coolant system.

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

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

Symptom Possible Cause Corrective Action Section
The pump is noisy or cavitates. The coolant does not return to the coolant tank fast enough. Remove chip buildup. 1
The coolant level in the coolant tank is low. Fill the coolant tank.
Chips are stuck on the impeller, or the impeller is damaged. Remove and clean the impeller. 2
There is a motor bearing failure. Rotate the shaft by hand to check the bearings.
There is low coolant flow. The coolant does not return to the coolant tank fast enough. Remove chip buildup. 1
The coolant level in the coolant tank is low. Fill the coolant tank.
Chips are stuck on the impeller, or the impeller is damaged. Remove and clean the impeller. 2
The filter or pump intake is clogged. Clean the filter and check the pump intake for chips. 3
Chips are inside the coolant check-valve and the coolant output hose. Remove any chips in the coolant check-valve and coolant output hose. 4
Chips in the spindle head are reducing coolant flow. Clear chips from the spindle head. 5
There is no coolant flow and the coolant circuit breaker did not trip. The coolant pump connection or the I/O PCB does not have voltage. Measure the voltage at the I/O PCB. 6
The coolant pump motor does not receive voltage. Measure the voltage to the coolant pump motor. 7
Incorrect power phasing - the pump motor is running backward. Check the phasing indicators and change the incoming power cables, if necessary. 9
There is no coolant flow and the coolant circuit breaker tripped. The coolant pump motor has a short to ground. Measure the resistance to ground on the coolant pump motor. 8

Section 1

Symptoms: The pump is noisy or cavitates. There is low coolant flow.

Possible Cause: The coolant level in the coolant tank is low.

Chips build up in the auger trough [1], and the coolant return drain [2] on the enclosure pan. This slows the coolant from returning to the coolant tank.

Corrective Action:

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

Click the links, or go to diy.haascnc.com to complete these tasks:

Section 2

Symptoms: The pump is noisy or cavitates. There is low coolant flow.

Possible Cause: Chips are stuck on the impeller blades. The impeller is damaged.

Corrective Action:

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 or damage to the impeller [2].

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.

Section 3

Symptom: There is low coolant flow.

Possible Cause: The filter or pump intake is clogged.

Corrective Action:

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 link for Coolant Tank ‑ Maintenance, or search for the document by keywords on diy.haascnc.com.

Section 4

Symptom: There is low coolant flow.

Possible Cause: Chips are inside the coolant check-valve and the coolant output hose.

Corrective Action:

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.

Section 5

Symptom: There is low coolant flow.

Possible Cause: Chips in the spindle head are reducing coolant flow.

Corrective Action:

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.

Section 6

Symptom: There is no coolant flow and the coolant circuit breaker did not trip.

Possible Cause: The coolant pump motor does not receive voltage.

Corrective Action:

Press EMERGENCY STOP. Disconnect the coolant pump motor cable from the side of the machine. Release EMERGENCY STOP.

Press COOLANT. Measure the voltage from the connector labeled "LOW PRESSURE COOLANT" on the side of the machine. When you measure from winding to winding [1] (W) you should measure 240 VAC. Do not measure winding [1] (W) to ground [2] (G).

  • If you measure 240 VAC, go to Section 6 to check the motor and the cable.

If you do not measure 240 VAC, measure the voltage from lead to lead at the P43 connector for the Classic Haas Control machines on the I/O PCB. Measure the voltage from lead to lead at the P29 connector for Next Generation Control machines.

  • If you measure 240 VAC, the cable from the I/O PCB to the connector labeled "LOW PRESSURE COOLANT" on the side of the machine is at fault.
  • If you do not measure 240 VAC, go to diy.haascnc.com to troubleshoot the I/O PCB.

Section 7

Symptom: There is no coolant flow and the coolant circuit breaker did not trip.

Possible Cause: The coolant pump motor does not work.

Corrective Action:

Complete the checks in Section 5.

Press COOLANT. 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, the cable is at fault.

Section 8

Symptom: There is no coolant flow and the coolant circuit breaker tripped.

Possible Cause: The coolant pump motor has a short to ground or a mechanical fault.

Corrective Action:

Press EMERGENCY STOP. Disconnect the coolant pump motor cable from the "LOW PRESSURE COOLANT" connector on the side of the machine.

Check for a short to ground. Measure the resistance at the motor cable for each winding [1] (W), to ground [2] (G). The reading must be infinite.

  • If you read zero or any continuity, the motor has a short.
  • If the reading is infinite, check for a mechanical fault in the coolant pump motor. Go to Section 2.

 

 

Check at the pump power connector for open leads:

  • Single phase: leg-to-leg resistance must be less than 5 Ohms.
  • 3-phase: all three ways ( W1-W2, W2-W3, and W3-W1) must be less than 8 Ohms.

Section 9

Symptoms: There is no coolant flow and the coolant circuit breaker did not trip.

Possible Cause: Incorrect power phasing - the pump motor is running backward.

Corrective Action:

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.

Be aware: Many service and repair procedures should be done only by authorized personnel. The service technicians at your Haas Factory Outlet (HFO) have the training, experience, and are certified to do these tasks safely and correctly. You should not do machine repair or service procedures unless you are qualified and knowledgeable about the processes.

Danger: Some service procedures can be dangerous or life-threatening. DO NOT attempt a procedure that you do not completely understand. Contact your Haas Factory Outlet (HFO) and schedule a service technician visit if you have any doubts about doing a procedure.

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