Polymer treatments have been used in boilers for many years. The reliability and the life expectancy of boilers have been compromised by severe chemical attack resulting in corroded tubes at different locations in the boilers. In some cases the attack profile is consistent with corrosion caused by chelant chemistry (thinning, glassy, smooth and
featureless surfaces) when the real root cause is a misapplied "all polymer" program. However, it has been demonstrated that an all polymer program; if applied properly is not corrosive. Presented in this paper is the failure mechanisms related to the polymer corrosion,
including the root causes: high levels of residual polymer, low hydroxide alkalinity, and high cycles of concentration in conjunction with prior acid cleaning. Further, it provides corrective actions and recommends practices for monitoring to aid in the mitigation of polymer corrosion and enhance the overall condition of the boilers.