OMTech CW-3000 Water Chiller

OMTech rates it at 50W of heat moved for every 1°C the water sits above the room. That figure lets you estimate where your water will settle. A CO2 tube turns most of its electrical input into heat rather than light, so a 40W-class K40 tube working hard sends a few hundred watts into the water. At around 300W of heat, the CW-3000 settles roughly 6°C above room temperature.

What the CW-3000 does better than a bucket:

• a steady 2.6 gpm flow through the tube
• a closed, enclosed 9-litre tank that keeps dust out and slows evaporation
• a digital display, indicator lights and alarms from internal sensors
• one box instead of a bucket, pump and extension cord on the floor

Treat the 6°C figure as a rough guide. The real gap depends on the tube current you run, how long each job lasts, and how clean the radiator is. Short engraves barely warm the loop; a long cutting session pushes it to its settled point.

For a K40 in a cool room it is a real step up. In a hot room it is a better bucket, not a cure.

K40 owners commonly aim to keep tube water below about 20 to 25°C for full power and a long tube life. Warm water lowers the tube's output and speeds its ageing. No amount of radiator fan will push water below the air it is blowing with.

Ways to live with a passive cooler through summer:

• Cool the room, not the water: run the laser in the coolest space you have, or in the morning.
• Shorten jobs and let the water recover between long cuts.
• Lower the current. Less current means less heat and a longer-lived tube anyway.
• Keep the unit fed with cool air, away from the laser's exhaust and any heater or sunny wall.

If your shop sits hot for months, budget for a refrigerated chiller instead. The CW-3000 then still has a place as a closed loop for spring and autumn, or for a second machine.

The tube's safe current and how heat ages it are covered in the K40 tube and power supply guide. Keep an eye on both the meter and the water temperature when you set cutting power.

1. Unplug the laser and drain the old bucket loop, including the hoses.
2. Place the unit on the floor or a low shelf beside the laser, with its radiator vents clear of walls.
3. Connect the hoses. Run the chiller's outlet to the tube's inlet and the tube's outlet back to the chiller. Feed in at the lower nipple so rising bubbles are pushed out the top.
4. Clamp every joint. A hose that slips off a glass nipple floods the tube bay.
5. Fill with distilled water or CO2 laser coolant through the top, watching the window.
6. Run the pump and bleed the tube. Watch for trapped bubbles at the top of the water jacket and clear them before firing.
7. Test the alarms. Pinch the return hose briefly and confirm the flow alarm sounds.

A chiller alarm warns you; it does not stop the laser on its own. Wire a flow switch into your K40's water-protect input, or into an upgrade board such as the MEFORE controller that has one, so the tube cannot fire dry.

Keep the hose runs short and free of kinks, and route them away from the tube's high-voltage lead. Water and high voltage in the same corner of a cabinet is a combination to design out, not manage.

For an unheated shop, fill with OMTech CO2 laser coolant. The 9-litre tank takes about three jugs.

A routine that keeps it working:

• Monthly: vacuum or blow dust off the radiator fins and fan grilles, with the unit unplugged.
• Every session: check the level through the window and glance at the display before firing.
• Every few months: drain, flush and refill with fresh distilled water or coolant.
• Any time: check hoses for stiffness, cracks and slime.

OMTech offers this CW-3000 under two product codes, one described for lasers up to 50W and one for 40W K40 machines. Both describe the same unit: 9-litre tank, 2.6 gpm flow, brass ports and 50W per degree. Either one does the job.

If the display reads higher than usual for the room and the job, check the fins before anything else. A dusty radiator is a likely reason a passive cooler loses ground.

How it compares:

• The Cloudray CW-3000 is the same class of cooler, with 10mm barbed connectors and named flow and over-temperature alarms.
• OMTech also sells the K40+ with a CW-3000 in the box, for buyers still choosing a machine; see the OMTech K40+ breakdown.

Measure the floor space for a 19 by 11 by 15 inch unit and check the tube's hose size against the brass ports. Then decide honestly whether your room runs cool enough for a passive cooler. Cooling belongs among the first fixes in the K40 upgrade order.