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Check coolant tank level

Open electrical cabinet door and visually inspect coolant tank. Level should be above minimum fill line (typically 2-3 inches from bottom).

Ensure machine is in EMERGENCY STOP before opening electrical cabinet

Refill coolant tank

Add appropriate coolant mixture (typically 5-10% concentration) until level reaches maximum fill line. Use only Haas-approved coolant or equivalent.

Check coolant concentration with refractometer - low concentration can cause biological growth and pump issues

Prime pump system

Press COOLANT button on control panel to manually activate pump and purge air from lines. Monitor pressure gauge if equipped.

May take 30-60 seconds to fully prime system after refill

Reset alarm and test

Press RESET button, then test coolant flow with M08 command in MDI mode.

Do not run spindle without confirmed coolant flow

Locate coolant filter assembly

Find coolant filter housing in electrical cabinet, typically mounted near coolant tank with clear or metal housing.

Ensure EMERGENCY STOP is engaged and coolant pump is off

Remove and inspect filter

Unscrew filter housing (turn counterclockwise), remove filter element and inspect for debris, metal chips, or biological growth.

Take photo of filter orientation before removal for proper reinstallation

Clean or replace filter

If cleanable type, rinse with clean water and compressed air. If disposable, install new filter element with same micron rating (typically 25-50 micron).

Ensure O-ring seals are properly seated to prevent leaks

Check tank strainer

Inspect suction strainer in coolant tank, clean debris from mesh screen using brush and compressed air.

Replace strainer if mesh is damaged or severely clogged

Locate pressure switch

Find coolant pressure switch on coolant manifold or pump outlet, typically a small switch with electrical connector and pressure port.

Verify EMERGENCY STOP is active before electrical work

Check switch operation

With coolant pump running, gently tap switch body and observe if alarm clears. Check electrical connections for corrosion or looseness.

Use multimeter to check continuity across switch contacts while pump is running

Verify pressure setting

Check switch pressure rating (stamped on body) - should be 15-25 PSI for most Haas machines. Compare to actual system pressure if gauge available.

Pressure switches can drift over time due to coolant contamination

Replace pressure switch

If switch is faulty, disconnect electrical connector, unscrew switch (use thread sealant on replacement), and reconnect wiring.

Use proper thread sealant to prevent coolant leaks

Check pump motor operation

Listen for unusual noises when coolant is activated - grinding, squealing, or no sound may indicate motor or coupling issues.

Normal pump operation should have steady humming sound without vibration

Inspect pump coupling

Check flexible coupling between motor and pump for cracks, wear, or separation. Look for coolant leaks around pump housing.

Disconnect power before inspecting coupling area

Test pump output flow

Disconnect coolant line at nozzle and observe flow rate when pump is activated. Compare to normal flow pattern.

Weak or intermittent flow indicates internal pump wear

Check pump motor current

Use clamp meter to measure motor current draw - significantly high or low current indicates motor problems.

This step requires electrical measurement skills - contact service if unsure

Inspect suction line connections

Check all fittings and hose connections between coolant tank and pump inlet for signs of air leaks or loose connections.

Small air leaks may only be visible when pump is running

Check pump housing seals

Inspect pump housing and shaft seals for coolant leaks or air ingress points. Look for white residue or corrosion.

Do not operate pump with damaged seals as this can cause motor damage

Test system for air bubbles

Observe coolant flow at nozzles for excessive air bubbles which indicate air ingress in suction side of system.

Some air bubbles are normal, but continuous stream of bubbles indicates leak

Repair identified leaks

Tighten loose connections, replace damaged hoses, or reseal pump housing as needed. Use appropriate thread sealant on fittings.

Ensure all connections are properly torqued to prevent future leaks