Above photo from L-R: Anh Tran (SJW Superintendent of Meter Shop), Ben Gottfried (Neptune), Matt Emslie (Neptune) and Jonathan Jethro (MARS).
SJW’s Meter Shop hosted our technology partners Neptune and MARS to help solve a mystery. When testing the new large Sensus Mach 10 meters, there was an issue of over-registering water at high flows. This causes the meter to fail our rigorous testing. Meters goes through rigorous and documented testing at low, medium and high water flows to make sure they are registering accurately.
All our internal tests and records showed the MARS test bench to be working accurately and Sensus double-checked that the meters were accurate at the factory. But why were the meters failing at the high water flows?
With some combined effort, the secret was finally unveiled. At the water tank outside the meter shop, there are two automated valves.
The first is the discharge valve. This valve is located outside just before the tank and controls the water flow into the tank itself. The second is a tank drain valve. This valve will open during the tank draining sequence and also during the purge sequence. The purpose of this valve is to stop water from draining during a test and allow water to drain after the testing and purging sequences are completed.
We believe that over time, the tank drain closing time increased. By changing the 7-second drain closing time to 30 seconds, there’s now plenty of time for the drain valve to close before the discharge valve opens. Mystery solved!
The changes were certified by MARS and the Sensus meters were tested. They passed with flying colors.
Thank you to Anh Tran, Meter Shop Superintendent, the entire Meter Shop Staff and our partners from Neptune and MARS for ensuring meters are tested and working properly so our customers can receive accurate bills.