Flow Switch Protects Chem-Gard Pumps

Two CG-KY300 pumps were installed at the City of Houston Southwest Wastewater Treatment Plant. These transfer pumps moved NaOCl from bulk storage to day tanks. This concentrated NaOCl is commonly used for odor control.


During the first 18 months of installation, operators ran the pumps without turning on the water supply to the double seal water jacket. On two of these occasions, the glass filled Teflon® rotating face heated up and began leaking sodium hypochlorite. The first episode was caught in time requiring only replacement of the seals. Further neglect after the second episode resulted in the need for a pedestal sub assembly including shaft and seals. At this point the plant operators were not pleased with the Chem Gard’s performance. Replacement of these pumps were on a “projects-to-do” list at Lockwood Andrews and Newnam, a local engineering firm.


Once the pumps were rebuilt a second time, we recommended the installation of McDonell FS1 flow sensors from the solenoid valve. So that the motor coil would not be close starting the pumps. These flow sensors were installed, and we are pleased to say that the pumps have operated without further problems for the following years. Thankfully, the Chem-Gards were no longer on the “projects-to-do” lists and Vanton’s reputation had been vindicated with both the city and with Engineering firms.


After a positive experience having this problem solved, we strongly recommend the installation of the McDonnell switch wherever operators are relied on to start and stop Chem-Gard pumps.