We have a job where the residual pressure recorded during the backflow test is lower than expected. The hydrant used for the original water test is about 10ft lower than the system riser and has a flow test result of 72PSI static, 62PSI residual, flowing 902GPM (off a circulating system). I had my fitter install a pressure gauge before the 1st check on the BFP and the we recorded a static of 67PSI but a residual of 50PSI at a flow of 715GPM. I confirmed with the water utility that the gate valve for the water lead in is fully open and that no pumps or valves have been shut off for water main breaks or maintenance. Unfortunately, they will not run a new flow test in winter. Any ideas as to what is causing the low residual pressure? Thanks, Dewayne Martinez Design Build Fire Protection New Berlin, WI _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum
For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field)
