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:
- 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. Go to the document diy.haascnc.com to troubleshoot the coolant level sensor..
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.
- 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.
- 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 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:

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.