what would cause low pressure in the system for the fire pump
what would cause low pressure in the system for the fire pump
(OP)
At our facility we had a supervisory alarm go off for fire pump running due to low pressure. We had the same problem couple weeks ago with our jockey pump low pressure. The fire alarm is not going into full bells and whistles just a supervisory and after a little bit the pressure goes back to normal. Could this be from the suction side if we are not getting enough pressure from city or is there something in the sprinkler lines itself? Thanks Jay





RE: what would cause low pressure in the system for the fire pump
It shouldn't be the city pressure fluctuating. If you look at your pump layout, you'll see that every time a pipe connects the discharge to the suction (Bypass, pressure sensing, thru the pump) there is a check valve.
When you say "the pressure goes back to normal", do you mean that the fire pump shuts off? If it was indeed a low pressure condition that started the pump, it should not be able to automatically shut down (got to keep dumping the wet stuff on the red stuff if a fire happens).
The operation manual for the controller should be behind the front door of the controller. The first thing I would do is read up on the automatic weekly run test.
RE: what would cause low pressure in the system for the fire pump
And, get that fire pump changed to manual shut off. The jockey is fine as automatic shut off, but fix the fire pump to manual shut off.
Travis Mack
MFP Design, LLC
www.mfpdesign.com
RE: what would cause low pressure in the system for the fire pump
Contact the company that does the annual inspection and have them trouble shoot
Before something gets messed up and dOes not work when it needs to
RE: what would cause low pressure in the system for the fire pump
Look through your controller configurations. Pressure points should be set as follows:
Fire Pump Stop: Churn pressure (data plate) + Static Pressure (inlet gauge)
Jockey Start: Pump Stop minus 10 psi
Fire Pump Start: Jockey Start minus 5 psi
After typing all this out, one more thought. Do you have pressure relief valves on your system? One small half inch one not set properly could potentially dump enough water to start the pump. But then your flow switch should pick it up...
RE: what would cause low pressure in the system for the fire pump
Travis Mack
MFP Design, LLC
www.mfpdesign.com
RE: what would cause low pressure in the system for the fire pump
Troubleshooting Mercoid Switches
Troubleshoot system check valve
RE: what would cause low pressure in the system for the fire pump
I've been testing fire pumps and had alarms go off in neighboring buildings because I sucked water out of their buildings. I also had one customer whose system had a single check valve that had disconnected their waterflow alarms because every time some one used the car wash down the street, their alarms would sound.
I've encountered similar problems to what you describe in small loop systems that are usually attatched to dry systems. Small volume systems are way touchier than similar systems hooked to wet systems.
RE: what would cause low pressure in the system for the fire pump
RE: what would cause low pressure in the system for the fire pump
RE: what would cause low pressure in the system for the fire pump
If it is underground leaking there is a company called Leak Detectors in Illinois. I have used them 5~6 times in 34 years when we could not find the water leaks but Nelson works around the country and all I can say is he has always helped us AND he has helped those I recommended him to. I suspect he has some kind of electronic dowsing rod, he says no.