Either the flow switch is broke or there is something seriously restricting flow some place. FS is 7 or 10 gpm. So if it ain't broke you are getting less than that flow. Even 15 psi on a 4.2 head is 16 gpm. More than enough to trip the flow switch. I suppose there is a 3rd option the jockey pump is really small in GPM and the settings on the fire pump are not right.
Chris Cahill, P.E. Fire Protection Engineer Sentry Fire Protection, Inc. 763-658-4483 763-658-4921 fax Email: [email protected] Mail: P.O. Box 69 Waverly, MN 55390 Location: 4439 Hwy 12 SW Waverly, MN 55390 -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Todd Williams Sent: Monday, November 02, 2009 10:07 AM To: [email protected] Subject: pump failure/flow alarm A situation came up this morning that I probably should know the answer to, but I don't. A building is protected by a 500 gpm at 40 psi diesel pump taking suction from a tank (no public water). The pump feeds to 2 sprinkler risers with riser checks and flow switches. The jockey pump pressure is set to approximately 50 psi. If the inspector's test opens and the pump does not turn on, there is not enough flow in the system to activate the flow switch. Consequently, if a sprinkler goes off and the pump does not activate, then no alarm is sent. Having never run into this or heard of it being tested, I don't know if this is normal but it seems like it shouldn't be. Is this normal? Is it ever tested? My first reaction is what is the delay on the flow switch set to (30 seconds). I told them to set to delay to 0 and see what happens. It may be just a situation of getting the setting right. Thoughts? Todd G. Williams, PE Fire Protection Design/Consulting Stonington, Connecticut www.fpdc.com 860.535.2080 _______________________________________________ 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) _______________________________________________ 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)
