Hale RSD - Manual (Page 124)

❑ Cavitation
124 Appendix F: Cavitation
Hale Products, Inc., Nov.2005, Rev-A
❑ Consider the piping within the truck. Suction losses can result from addi-
tional suction piping added to the fire pump during assembly.
❑ Follow the maintenance and inspection procedures.
❑ Cavitation can also occur when air enters the pump. The pump could be
primed; however, air leaks can cause rough operation and an increase of
engine speed without an increase in pressure or flow. If an air leak is sus-
pected, refer to Section 5 “Troubleshooting.”
❑ Using “soft sleeve” vs. “hard sleeve.” The soft sleeve has an advantage as
the sleeve collapses under a partial vacuum (visual indication of cavitation),
even though the intake gauge might still indicate a positive pressure. With a
hard sleeve, the only indicator would be the intake gauge, which is inaccu-
rate at close to the ZERO (0) reading.
Strainers:
Clogged strainers or suction strainer selection, restricting flow. Verify the
hose strainers and suction strainer are clear (unobstructed) and located
deep enough in the water source to insure constant, uninterrupted water
flow.
Note: Strainer type, basket vs. barrel, also has an affect on water flow which can con-
tribute to flow restrictions, thus causing cavitation and reduced pump performance,
especially during high drafting conditions. Basket strainers are preferred by Hale due
to their overall suction and straining area.
❑ Turbulence or whirlpools in the hose line can be caused by excessive operat-
ing pressures from the intake source. Carefully monitor and reduce pres-
sures as needed.
Hose Diameter
in. (mm)
3”
(76)
4”
(102)
4.5”
(127)
5”
(127)
6”
(152)
Dual
6” (152)
Flow - gpm (lpm) Lift Loss (gpm (lpm)
250 (946) 5.2 (20)
350 (1,325) 2.5 (9.5)
500 (1,893) 5.0 (19) 3.6 (13.6)
750 2,839) 11.4 (43) 8.0 (30) 4.7 (18 1.9 (7.2)
1,000 (3,785) 14.5 (55) 8.5 (32) 3.4 (13)
1,250 (4,732) 13 (49) 5.2 (20)
1,500 (5,678) 7.6 (29) 1.9 (7.2)
1,750 (6,625) 10.4 (39) 2.6 (10)
2,000 (7,571) 3.4 (13)
2,500 (9,464) 5.2 (20)
Figure F-4: Hose Size vs. Pump Rating Capacity