What causes Haas alarm 172?

TSC pump motor failure or contactor not energizing due to electrical fault. Clogged coolant filter in TSC line restricting flow and preventing pressure buildup. TSC pressure switch failure, incorrect adjustment, or disconnected wiring to MOCON input. Air trapped in TSC lines after tank service or coolant change preventing pressure switch activation. Drawbar or spindle internal coolant passages blocked with chips or debris.

How do I fix Haas alarm 172?

1. Step 1: Verify TSC coolant tank has adequate fluid level and TSC pump can be heard running when M08 is commanded 2. Step 2: Check Diagnostics > Inputs page for TSC pressure switch input status, should close within 3 to 5 seconds of pump start 3. Step 3: Inspect TSC filter assembly and replace filter element if clogged or restricted 4. Step 4: Manually actuate TSC pressure switch and verify signal reaches MOCON board, adjust switch setpoint if needed (typically 200 to 300 PSI) 5. Step 5: Bleed air from TSC system by running pump with tool holder removed and observing coolant flow from spindle nose 6. Step 6: Check TSC pump motor current draw and contactor operation, verify 115VAC at pump motor when commanded, replace pump or check MOCON output circuit if no voltage present

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Haas Controller

Coolant · Intermediate · 20-60 minutes

Alarm 172

Haas Alarm 172 - Through Spindle Coolant Fault

Alarm 172 fires when the control does not detect adequate through-spindle coolant pressure within the timeout period after commanding TSC on. The system monitors pressure switch/transducer input against Parameter 278 threshold and times out based on Parameter 279 setting.

HaasCoolantIntermediate20-60 minutes

172

Haas Alarm 172 - Through Spindle Coolant Fault

Thru Spindle Coolant

Root Cause Summary

Alarm 172 fires when the control does not detect adequate through-spindle coolant pressure within the timeout period after commanding TSC on. The system monitors pressure switch/transducer input against Parameter 278 threshold and times out based on Parameter 279 setting.

Safety

TSC systems operate at 300-1200 PSI—wear safety glasses and ensure no one is near spindle nose when testing flow to avoid high-pressure coolant spray injury
Lock out main disconnect and tag machine before inspecting or replacing TSC pressure switch or working on high-pressure plumbing to prevent unexpected pump activation
Do not run TSC pump dry for more than 5-10 seconds—this can overheat and destroy pump seals and impeller, leading to costly pump replacement

Causes and Fixes

1
Check coolant tank level
Verify TSC tank has adequate coolant above minimum level sensor. Fill if below 25% capacity.
Use only recommended coolant mixture ratio per machine manual
2
Bleed air from system
Access COOLANT menu, select TSC PRIME function to purge air from lines and rotary union.
Run prime cycle 2-3 times if system was completely drained
3
Verify pressure switch operation
Check M-codes > COOLANT display for TSC pressure switch status during prime cycle.
Switch should change state when pressure reaches Parameter 278 threshold

DIY Feasiblehigh confidence

Call a technician if:

·Pump motor replacement required
·Electrical troubleshooting beyond basic connections
·Rotary union replacement needed

Prevention

Maintain proper coolant levels and mixture ratios
Replace TSC filter every 6 months
Perform weekly TSC system pressure checks
Clean spindle nozzles during routine maintenance

Common Mistakes

Ignoring low coolant level warnings
Using incorrect coolant mixture
Not bleeding air after system service
Setting Parameter 278 too high for pump capacity

Related Alarms

173 174 175

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Always verify with your machine manual or a certified technician before performing service procedures.