Cleaning frequency depends on the water composition and the operating mode. For example, one of the units, supplied by ReinnolC, has been in operation at our customer’s Thermal Power Station since 2001 with no cleaning at all. For wastewater treatment units we developed an operating mode for preventing deposits by using scale inhibitors. The mode allows us to completely prevent scaling. Deposit formation is possible, if the operating mode is disrupted (if reagent’s supply is disrupted due to the metering pumps` failure; if purging is reduced, etc.). Cleaning frequency depends on keeping an accurate operating mode and is required no more than once or twice a year. The cleaning process is the same as for conventional shell&tube heat exchangers. The water chambers need to be open and cleaned with a high-pressure water cleaner. Clean-in-place washing with acid solution is also possible.