Dewayne, This may not be feasible but I had a similar problem with air in my dry pipe props at the college. I used a tank mounted compressor so I don't have a cycling problem there but my "systems" consist of about four feet of four in pipe. In simulating a trip test the time was so fast as to be unrecordable. I attached a big tank (maybe 150 gallons) to the risers and now have a decent volume. Perhaps you could add a "length of main," i.e., volume, between your discharge check valve from the pump and the PRV with a similar set-up.
On Wed, Dec 31, 2008 at 10:55 AM, Dewayne Martinez <[email protected]> wrote: > We have a situation on a large system that has the jockey pump piped to > the suction side of a 10" pressure reducing valve. The fire pump churns > at 210psi and the prv is set for 175psi discharge. Because there is no > volume of pipe prior to the prv my jockey pump cycles on and off every > 5-7 seconds which will eventually damage the jockey controller contactor > and cause failure. We tried moving the sensing line from the jockey line > to the bulk main which did not change the operation of the jockey pump. > We contacted Cla-Val, the manufacture of the prv, and they suggested > piping the jockey pump to the discharge side of the prv. They said the > pressure is bleeding through the 1/8" orifice of the CRL valve which is > located on the trim of the prv. NFPA 20 recommends setting on/off > pressures at churn of fire pump which in this case is 210psi. If we pipe > the jockey after the prv and set off pressure at 175psi and on at 165psi > and the on pressure of the fire pump at 160psi this will produce a 50psi > hammer. What would be the best way to correct this problem? > > Thanks, > > Dewayne > > _______________________________________________ > Sprinklerforum mailing list > http://lists.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) > -- Ron Greenman at home.... _______________________________________________ Sprinklerforum mailing list http://lists.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)
