CO₂ Laser Tube Cooling: What To Check Before Ordering A CO₂ laser that weakens during a long run isn't always a tube failure. Unstable cooling, poor water flow, or a mismatch with the power supply can cause the same symptoms. This guide explains how heat affects tube performance, what machine details to prepare before requesting a quote, how to check the cooling loop, and which questions to ask a manufacturer about testing, lifespan and OEM support.