Service Home P-COOL - Troubleshooting Guide - TG0106

P-COOL - Troubleshooting Guide - TG0106

5.6 P-COOL - Troubleshooting

Last updated: 10/14/2025

P-COOL - Troubleshooting Guide

TG0106

Revision B - 6/2026

Introduction

The Programmable Coolant Nozzle is a multi-position nozzle that automatically directs coolant precisely at the cutting tool.

P-COOL Inspection Checklist

P-COOL Assembly Diagram

Caution: OPENING THE P-COOL UNIT IS NOT A RECOMMENDED STEP IN THE TROUBLESHOOTING GUIDE AND MAY VOID YOUR WARRANTY. 

[1] Position switch

[2] Home switch

[3] Home flag

[4] Nozzle Swivel Fitting

[5] Count Gear

[6] Seals

Symptom Table

Nozzle Alignment

1

The push connect type nozzle allows for some deviation in the P-COOL coolant stream. 

The nozzle can be twisted to make small adjustment to the alignment of coolant stream. If the nozzle is not loose enough to be moved by hand, pull the nozzle out gently until it clicks. The nozzle should now be free to rotate by hand. 

Twist the nozzle incrementally, turning on coolant between adjustments, until the coolant hits the tool. 

2

UMC Machines Only: 

P-COOL units on UMC machines are attached to the spindle with a bracket. To adjust the alignment of the P-COOL, loosen the bolts that secure the P-COOL to the bracket [1]. 

Push the P-COOL in the desired direction [2] and hold it in place while tightening the bolts. 

Test the alignment by turning on the coolant. 

 

Symptom Possible Cause Corrective Action
Alarm 196 COOLANT SPIGOT FAILURE The P-COOL could not obtain the commanded position in the allotted time.  Check for drag in the P-COOL nozzle's swivel fitting. Verify that there are no other reasons for the nozzle to be moving slowly. 
There is no power to the P-COOL.  Measure the incoming voltage to the P-COOL.
The P-COOL moves up and down without stopping.  Make sure the cabling is undamaged, and the connector pins are sealed properly. 
P-COOL lost count of position Power cycle the machine to re-home the P-COOL.
There is low coolant flow from the nozzle.  Chips have clogged the P-COOL nozzle or the filters.  Verify that check valves leading to P-COOL are open. Clean and remove chips from the P-COOL nozzle and the filters. 
Chips have clogged the check valve or the coolant hoses.  Verify that check valves leading to P-COOL are open. Clean and remove chips from the check valve and coolant hoses.
HMC Mills: The P-COOL spigot moves in the opposite direction.  Parameter 209.09 SPIGOT KEY INVERT is not set correctly.   Make sure that Parameter 209.09 is set correctly.  This parameter inverts the direction the spigot moves when the CLNT UP / CLNT DOWN buttons are pressed. 
P-COOL will not position correctly or skips positions. The P-COOL position switch is damaged and does not count correctly. 

Use M34/M35 to move the spigot up and down in 1 position increments. A 0.05 second dwell will be needed with each movement. Check that all positions are reached correctly. 

HSG-A 4-4-2023
Counting gear is not aligned properly to position switch.

Power cycle the machine to home the unit.

 NOTE: When the Pcool is in motion and that action is interrupted by a loss of power, then it is possible that the unit will lose position.
Alarm 9806 SHORT CIRCUIT Short circuit on P-Cool Cable or P-Cool Motor.

Conduct a visual inspection of the cable assembly for any cable cut, pinch or damage that could cause the cable to fail. Then perform a continuity test of both ends of the cable assembly. 

IMPORTANT: If the cable is not damaged and passes the continuity tests, an error report MUST be taken and added to the machine history for troubleshooting the motor. If an error report is not taken there is a risk of warranty being rejected.

See Alarm Troubleshooting section below.

Alarm Troubleshooting

Caution: OPENING THE P-COOL UNIT IS NOT A RECOMMENDED STEP IN THE TROUBLESHOOTING GUIDE AND MAY VOID YOUR WARRANTY. 

1

Clean the P-COOL unit, removing any chips and debris.

Inspect the swivel fitting (4) attached to the nozzle and determine if it is bound or fixed in position.

Reset any alarms and power cycle the machine. The pcool will home itself, actuating the home switch (2) then reset the count switch (1) position..

NOTE: When the P-COOL is in motion and that action is interrupted by a loss of power, then it is possible that the unit will lose position. Homing the P-COOL fixes this position error. To do this, power cycle the machine.

I/O confirmation

2

Monitor the following inputs and outputs and verify their values change across all positions by manually commanding the unit.

Use the CLNT UP or CLNT DOWN buttons on the control to actuate the nozzle.

NAME P# TYPE SW# HW# CONNECTOR INITIAL VALUE
PROGRAMMABLE_COOLANT_POSITION_MARK P39 INPUT 50 IO16 P39.3 1
PROGRAMMABLE_COOLANT_MOTOR_CW P39 OUTPUT 61 0031 P39.1 0
PROGRAMMABLE_COOLANT_MOTOR_CCW P39 OUTPUT 62 0030 P39.2 0
PCOOL_CURRENT P34 A-INPUT 34 A34 - -

Signal Confirmation

3

Verify that the cable connection on the P-COOLunit is properly secured.

Verify that the cable connection for the P-COOL cable at the spindle head bracket is secure.

Verify the cable is not damaged along its length.

Verify the connectors at P35 on the I/O PCB, are properly seated, pins are in good condition and not contaminated.

4

Run this program in MDI mode:

M34;
G04 P2. ;
M35;
G04 P2. ;
M99 ;

While the program runs, use a multimeter with needle-tip probes to measure the resistance from pin 3 (black) to 2 (brown). The meter will alternate between a value and OL, verifying the condition of the position switch.

While the program runs, use a multimeter with needle-tip probes to measure the voltage from pin 4 (white) to 2 (brown). The voltage must measure 12 VDC. This will verify that the position switch is supplied power.

Do not measure the voltage with the cable disconnected.

If there is no voltage, check for continuity in the cable between the P-COOL and the connector bracket. If there is no continuity, the cable is at fault. If there is continuity, the P-COOL assembly is at fault.

If there is voltage, refer to:

5

Do a visual inspection of the cable assembly for any cable cut, pinch or damage that could cause the cable to fail.

Do a continuity test of both ends of the cable assembly. 

There should be no continuity between these pins in a resting state:

  • Pins 4 (white) and 1 (Blue).    
  • Pins 4 (white) and 2 (brown).
  • pins 4 (white) and 3 (black). 

DATA COLLECTION ProgramS

6

Follow the Diagnostic Data Collection - Instructions to load the P-COOL diagnostic program PCOOL_SWEEP_COLLECT.

This test will record the position switch states and motor current draw while the unit is in continuous motion.

Insert a USB into the Haas Control. Copy the following program into MDI.

M222;
M34 P34;
G04 P2. ;
M35 P1;
G04 P2.;
M99; 

Manually arm the data collection by pressing F2.

Press cycle start to run the program. When the program is finished, the results will be saved as an OSC_DATA file. 

Upload the results of this test with the work order.

7

Follow the Diagnostic Data Collection - Instructions to load the P-COOL diagnostic program PCOOL_STEP_COLLECT.

This test will record the position switch states and motor current draw while the unit is in stepped motion.

To start this test, the P-COOL nozzle should be placed in its highest position.

Copy the following program into MDI.

M222;
M34;
G04 P2.;
M99;

Manually arm the data collection by pressing F2.

Press cycle start to run the program. When the program is finished, the results will be saved as an OSC_DATA file. 

Upload the results of this test with the work order.

Clogged Spigot, Filter and/or Check Valve

Make sure the ball valve for the coolant loop on the spindle head is fully open.

Remove any chips that are stuck in the P-COOL nozzle.

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

  1. Auxiliary Filter - The bag filters in the 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 - The Standard Filters need to be cleaned. Remove chips from the basket filter in the coolant tank.

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 wash-down hoses for chip buildup. Connect the coolant hoses.

Refer to the Standard Coolant - Tank - Maintenance procedure.

Electrical Diagram