Water Flow Fault
Lumenis Medical Laser
Severity:What Does This Error Mean?
A water flow fault on a Lumenis laser means the internal cooling system is not detecting adequate water flow through the cooling circuit. This fault prevents firing because the laser components — particularly the diodes or laser rod — require constant water cooling during operation. Firing without adequate cooling would cause immediate and irreversible damage.
Affected Models
- Lumenis LightSheer DUET
- Lumenis LightSheer ET
- Lumenis UltraPulse
- Lumenis AcuPulse CO2 Laser
- Lumenis VersaPulse
Common Causes
- Cooling water reservoir level low — needs topping up with distilled water
- Cooling pump failed or impeller blocked with mineral deposits
- Water flow sensor failed — giving a false low-flow reading
- Cooling circuit blocked — debris or mineral scale in the tubing or heat exchanger
- Internal water hose kinked or disconnected
How to Fix It
-
Check the coolant reservoir level.
Most Lumenis water-cooled lasers have an accessible coolant reservoir with a level indicator. If the level is low, top up with distilled water only — never use tap water (mineral deposits will block the cooling circuit over time) and never use antifreeze.
-
Power the device off, wait 5 minutes, and restart.
After topping up the reservoir, restart the system. The pump needs time to circulate the water and purge any air bubbles from the circuit before the flow sensor reads correctly.
-
If the reservoir is full and the fault persists, do not use the device.
A water flow fault with a full reservoir means the pump, flow sensor, or internal circuit has a fault. Do not attempt to fire the laser — without cooling, the diodes or laser rod will fail within seconds of operation.
-
Call Lumenis service.
Report the fault and the reservoir level at the time the fault appeared. An engineer will inspect the pump, flow sensor, and cooling circuit.
When to Call a Professional
Check the water reservoir level first — this is the only user-accessible fix. All other water flow fault causes require an authorised Lumenis service engineer. Do not attempt to open the device to inspect internal tubing.
Frequently Asked Questions
What type of water should I use in a Lumenis laser coolant system?
Always use distilled water or deionised water — never tap water, bottled mineral water, or any additive. Tap water contains minerals that deposit inside the cooling circuit over months of use, eventually blocking the tubing and heat exchanger. Some Lumenis models specify a particular coolant additive to prevent biological growth — check your device's maintenance manual.
How often should the Lumenis coolant be changed?
Lumenis typically recommends changing the coolant once per year as part of annual preventive maintenance. A Lumenis service engineer will flush the cooling circuit, refill with fresh distilled water, and check the flow rate during the annual service.