Because high velocities result in potential erosion of the film, a continuous feed is required to replenish the material on surfaces where it has been eroded. In addition, deposits destroy the protection afforded by such filming amines, and they do not protect well in areas where pitting has already occurred. The presence of dissolved solids degrades or precipitates traditional filming amines significantly and renders them ineffective in a condensate contaminated by carryover from the boiler or by leakage in the process (e.g., oil in refineries). In addition, use of filming amines should be avoided when organic contamination of the steam is common to prevent stripping of the amine film by solvent-type organics.

Ferric oxide also presents a potential problem because it can cause polymerization of the amine, the results of which, combined with degradation products formed in the condensate, can accelerate corrosion. Over-treatment, whether caused by overfeed, poor distribution, or high recycling with the returned condensate, aggravates these problems.

Because filming amines have an affinity for underlying metal, they may undercut iron oxide deposits causing rapid slough-off, often a deterrent to their use in older plants. Sloughed-off iron oxide deposits mix with the adsorbed amine, causing blockage of traps and valves in the condensate system and in the spray nozzles of the deaerator. Even a gradual increase of amine dosage is often ineffective because pH excursions can break down the films formed by such amines. Filming amines are most effectively used on uncorroded metal in systems where condensate return is not high. They are generally not recommended for use in systems with high condensate return, in which the degraded or polymerized amine that is returned can result in deposit formation.

Because filming amines are most effective when applied to uncorroded metal, their use is most desirable in newer systems. The problems created by applying them to previously corroded metal surfaces can be overcome by the accompanying use of volatile oxygen scavengers. By passivating the metal surface, the scavenger "prepares" it for the filming amine. Filming amine bonds to passivated magnetite surfaces are far more stable and effective than bonds to hematite.