Fire Pump Theory and Operation

Question 1

3 Primary Sections of the Modern Fire Pump

Answer 1

• Intake Manifold (lower half of pump body)
• Discharge Manifold (upper half of pump body)
• Centrifugal Pump Assembly (including impellers)

Question 2

JFRD Engines are powered by …

Answer 2

… six-cylinder turbo-charged diesel motors, manufactured by Caterpillar (C12 or C13) or Cummins (ISL series)

Question 3

Intake pressure …

Answer 3

… adds directly to pressure produced by the pump

Question 4

Pump Testing

Answer 4

• measures at volume while drafting at 3 different pressures
• 150 PSI (1500 GPM) 100% rated capacity
• 200 PSI (1050 GPM) 70% rated capacity
• 250 PSI (750 GPM) 50% rated capacity
• Volume at 150 PSI is called rated capacity

Question 5

Two Stage Pump

Answer 5

Pressure - series

Volume - parallel or capacity

Question 6

Electric Transfer Valve Failure

Answer 6

• Use 3/4” socket and socket wrench

Question 7

BIV

Answer 7

• Water control valve
• Spring operated pressure relief valve (150 PSI)
• Bleeder valve
• 5” Storz adapter
• Rated for drafting

Question 8

Electric Front and Rear Intake Valves

Answer 8

15 to 20 sec to fully open

Question 9

Discharge Piping

Answer 9

1” booster line to 4” LDH discharge

Question 10

Compound Gauges

Answer 10

• Pressure (PSI) and Vacuum (inHg)
• 0 to 600 PSI
• 0 to -30 inches Vacuum

Question 11

Electric Primer

Answer 11

• Rotary vane pump; pull handle
• Positive displacement pump (water and air)
• Creates vacuum in fire pump removing air

Best performance, set RPM between 1000 - 1200 when priming

Question 12

Pneumatic Primer

Answer 12

• Pressing a button
• All other features same as Electric Primer

Engines w/front intakes have 2 primers which should be operated simultaneously when using the front intake

Question 13

Alternative Priming Methods

Answer 13

• Partially open deck gun
• Partially open TANK FILL valve

Both work in the event of Primer failure

Question 14

Four Motor Functions to watch while Pumping

Answer 14

1. Coolant Temp : 180 - 220 degrees fully warmed up
2. Oil Pressure: 15 PSI (Idle) 35 - 45 PSI (at speed)
3. Transmission Temp: Under 300 degrees (normal)
4. Voltage: 13 to 14.5

Question 15

Pump Cooler/Recirculator

Answer 15

• flows less than 25 GPM
• use when hose lines charged but not flowing
• if supplied by tanker or hydrant, may overflow booster tank

Question 16

Thermal Dump Valve

Answer 16

• Temp activated at 140 degrees
• Discharges water into booster tank or on ground
• Resets once water temp cools

Question 17

Engine Cooler/Auxiliary Cooler

Answer 17

• Circulates cool water through radiator, keeping engine cool
• Does not mix with coolant
• Pump must be engaged to work
• Open any time coolant temp exceeds normal levels