HAAS® Alarm 120A — COOLANT PUMP OVERLOAD
Part of: our HAAS® alarm reference · covering 60 of the most common alarms.
What it means
The coolant pump is drawing too much current — its overload protection has tripped. Different from low coolant level.
Common causes
- Pump impeller jammed (large chip caught in it)
- Coolant tank empty or full of swarf, pump running dry
- Pump motor end-of-life
- Through-spindle coolant filter blocked
What to check first
- Switch off and clean the coolant tank — chip build-up is the usual culprit
- Check coolant level
- If TSC is fitted, check the high-pressure filter
- Persistent fault means a new pump
Prevention
Cabinet maintenance is the quiet hero. A 5-minute filter clean every fortnight prevents the vast majority of cabinet-temperature and drive-temperature alarms. Replace cabinet filters at the schedule the manual specifies, not when they look clogged — by then they're already restricting airflow.
If you’re still stuck
If you’ve worked through the checks above and the alarm hasn’t cleared — or if it cleared and came back — that’s the point to call. Persistent alarms after a reset usually mean a real component fault, and pushing through them risks turning a simple repair into a bigger one. Keith covers HAAS® breakdowns across the UK with same-day phone diagnosis.
A note on this guide. Alarm wording and numbering can vary by HAAS® machine model and software revision. The descriptions here are written in plain English to help you understand what the machine is reporting and what to check first — they’re not a substitute for the official HAAS® operator manual or for a qualified service engineer’s diagnosis. Always confirm the exact alarm message on your screen and consult your machine’s documentation before attempting any repair.