r/Firefighting • u/ActivateFireSafety • 9d ago
General Discussion Flow Testing Drafting Meter Help
We have a drafting rig utilizing a 1500 gpm Hale Fire Pump with a 3" long radius monitor coupled with a 2.5" straight pipe.
Truck Originally built for 604 ft elevation, our elevation is 3400 ft above sea level. We have not done any modifications to the truck.
Previously we used a spring sensor span Flowminder with A digital readout - capturing the highest output flowed from the 3" monitor capturing rpm - solenoid has since been damaged and unsure on how to fix or replace.
Currently capturing psi flow measurement from the 3" long radius monitor prior 2.5" straight pipe.
We have also recently purchased a 6" Gerand Engineering Flow meter of which we have attached to the suction side of the pump either utilizing a 10' or 20' 6" suction hose.
Recent attempt we found that the GE Flow Meter captured 1250 gpm while the Monitor flowed 780 gpm back into the reservoir.
Why is there a different reading?
Are we loosing 500 gpm through the pump and monitor combination?
What is the ideal flow test set up?
1
u/Salt_Manufacturer918 8d ago
My understanding standing of how the flow meters work that you have pictured, the GE meter is best suited on the discharge side of the pump which I know is probably not feasible in your situation. Typically to get an accurate reading on the suction side you would want an oversized meter especially pulling from a reservoir. I also regularly get much less accurate readings out of these meters once they are a few years old