Table 4-2. Unit Troubleshooting - Continued
TEST OR INSPECTION
FIREFIGHTING SYSTEM - Continued
PUMP FAILS TO PRIME OR LOSES PRIME - Continued
Step 2. No oil in priming tank.
With rotary primer, oil is usually required to maintain a tight rotor
Step 3. Check priming tank oil supply and replenish, if necessary.
Speeds much higher than those recommended do not
accelerate priming, and may actually damage priming pump.
Step 4. Engine speed too low.
Refer to operating instructions for correct priming speeds.
Step 5. Check for air leaks.
Clean and tighten all suction connections. Make sure suction hoses and gaskets are in good
Step 6. Check for dirt on suction strainer.
Remove all leaves, dirt, and other foreign material from suction strainer.
When drafting from shallow water source with mud, sand, or gravel bottom, protect suction
strainer in one of the following ways:
Suspend suction strainer from a log or other floating object to keep it off bottom. Anchor
float to prevent it from drifting into shallow water.
Remove top from a barrel. Sink barrel so open end is below water surface. Place suction
strainer inside barrel.
Make a suction box, using fine-mesh screen. Suspend suction strainer inside box.
Step 7. Check for defective priming valve.
Refer to Direct support maintenance level.