Steam Impingement is caused when unregulated steam/steam pressure makes contact at the bundle located at the inlet of the shell of the heat exchanger. Over 35 PSIG, we recommend reducing it down to 30 PSIG or less. For older tube bundles that haven't been replaced for many years steam impingement can be a valid reason to check your system to see if anything was replaced lately, or if anything isn’t working properly, as it may have caused the first bundle to fail (malfunctioning valve / trap, etc). Options to prevent consistent steam impingement is to make the top couple of rows heavier wall, and/or put a stainless steel steam impingement shroud on the bundle to help prevent the impingement. Nationwide Coils offers tube bundles for all makes and models!