Pit Document

Question 1

From the cab, how can you tell you are in pump

Answer 1

Hear and feel pump is engaged

“Pump engaged” and “ok to pump” light is on

Speedometer at 10-15 mph

Slight pressure on gas pedal engine doesn’t move

Question 2

From pump panel, how can you tell you’re in pump?

Answer 2

Light on pressure governor turns on
Pump panel light turns on
Red flashers near pump panel off
Pressure governor can be switched to pressure
Engine speed increase = increase in pump pressure

Question 3

If the air actuator in the cab fails, how do you engage the pump?

Answer 3

Transmission in neutral, parking brake set
In-cab pump shift control to “center position”
Manually push control rod on pump panel IN
Move in-cab pump shift control into pump position
“Pump engaged” light should turn on
Shift transmission into gear, “ok to pump” light turns on

Question 4

Explain how a centrifugal pump works

Answer 4

A centrifugal pump does not use positive displacement action to force water from the pump, rather it depends on the velocity of the water produced by centrifugal force to provide the necessary pump discharge pressure for effective operation

Question 5

Explains the path a drop of water takes through a centrifugal pump

Answer 5

A drop of water enters a centrifugal pump through the eye of the impeller. Water then comes in contact with the vanes of the impeller and it thrown by centrifugal force to the outside of the impeller. Water then travels through a gradually increasing cross-sectional area known as the volute. The gradually increasing size of waterway reduces velocity thus enabling the pressure to build up as the water exits the discharge of the pump.

Question 6

Explain the principles of the pressure governor.

Answer 6

The pressure governor system consists of a co outer, pressure transducer, control panel, throttle actuator, and a rpm counter.
Computer located on engine
Pressure transducer on discharge side of pump
Transducer senses pump discharge pressure and sends a signal to ECM. ECM will then control pressure by regulated engine rpm.

Question 7

What is the governed speed for a pierce quantum?

Answer 7

2175 rpm

Question 8

When the pressure governor is in THROTTLE mode, how many rpm’s is the engine raised when the toggle is moved 1 click?

Answer 8

25 rpm

Question 9

When the pressure governor is in the pressure mode, how many psi is the discharge pressure raised when the toggle switch is moved up 1 click?

Answer 9

4psi

Question 10

Explain the principles of a pressure relief valve

Answer 10

The main component of the pressure relief valve consist of a four-way valve, a strainer, a spring-loaded pilot valve, pressure chamber, dump line, and the main relief valve.
When the components of the relief valve are activated by turning on the four-way valve, water from the discharge side of the pump passes through the strainer and fills the pressure chamber.
The chamber is held closed by the adjustable spring loaded pilot valve. With excess pressure on the discharge side of the pump, it will overcome the spring-loaded pilot valve causing it to open.
Water from the pressure chamber, that was helping to hold the relief valve closed, is diverted through the dump line back to the intake side of the pump. This causes the main relief valve to open and bypass water from the discharge to the intake side of the pump relieving the excess pressure.

Question 11

Define cavitation

Answer 11

Cavitation is basically pumping more water out the pump than you have coming in. For instance, operating a pump at excessive speed, too high of an intake lift, restricting the intake, or any other factor that causes the pressure on the liquid to fall below its vapor pressure causes cavitation.
When this condition exists, the liquid vapor released in low-pressure regions of the pump forms bubbles. The bubbles are carried into the high-pressure sections of the impeller, where they collapse with considerable force. This may cause pitting near the impeller vane tips.

Question 12

What are the signs of cavitation?

Answer 12

Signs of cavitation are:
A sudden pressure or capacity loss
An increase in pump speed without corresponding increase in volume or pressure
Excessive pump vibration
Rattling sound resembling gravel going through the pump

Question 13

How can you overcome cavitation?

Answer 13

Reducing engine speed
Decrease gpms flowing
Find additional water supply

Question 14

Describe the cavitation protection feature of the Pierce pressure governor system

Answer 14

If water supply is reduced or interrupted the governor system first attempts to increase the pump discharge pressure by advancing engine speed until pressure is obtained or max govern speed is reached.
Engine will return to idle if discharge pressure remains less than 30 psi with engine speed of more than 2000 RPM for more than 5 seconds

Question 15

What is residual pressure?

Answer 15

Residual pressure is that part of the total available pressure not used to overcome friction loss or gravity by forcing water through pipe fittings, fire hose, and adapters. Residual means a remainder of that which is left.

Question 16

Define net pump pressure

Answer 16

Net pump pressure is the total work done by the pump to get the water into, through, and out of the pump, hose and nozzle’s. It is the sum of the pump pressure, suction, and lift losses

Question 17

How do you convert inches of mercury on the compound gauge to psi?

Answer 17

Multiply it by .5

Question 18

What is the compound gauge and how does it work?

Answer 18

The compound gauge is the gauge on the pump panel that registers pressure above atmospheric psi or below atmospheric in inches of mercury on the intake side of the pump. The gauge consists of two close coils called Bourdon tubes. As the pressure increases the tubes will uncoil, when the pressure reduces it will cause it to coil more tightly. This motion is transferred to a gear connected to the indicating needle at the pump panel.

Question 19

When would you change from pressure to volume in a two stage pump?

Answer 19

The transfer valve should be switched from pressure to volume when flowing 2/3 (1,000GPM) or more of the capacity of the pump

Question 20

At what pressure can the transfer valve be electronically operated?

Answer 20

250 psi

Question 21

How can The transfer valve be operated if the electronic switch fails?

Answer 21

If the electronic transfer switch fails, the transfer valve can be operated manually on the pump panel using the manual transfer valve wrench. Turning the wrench in a counterclockwise rotation transfers the valve into the pressure mode. Turning the wrench in a clockwise rotation transfers the valve into the volume mode. It is approximately 15 rotations in either direction and should never be operated over 75 PSI

Question 22

Why do pumpers have a priming pump? What type of priming pump does the pierce pumper use?

Answer 22

Because a centrifugal pump can not pump air, a priming pump is needed to create a lower pressure within the pump and intake hose so that water is forced up into the pump by atmospheric pressure. The type of pump used is a rotary vein type positive displacement.

Question 23

Describe the parts of the Pierce priming system.

Answer 23

A waterous electric prime consist of two components 1) a positive displacement priming pump 2) a priming valve.
The priming pump draws air out of the centrifugal pump through the priming valve.
The rotary vane pump contains one rotor with four vanes that slide in and out of the rotor.
Priming valve opens automatically during pump priming. When the valve is open, it allows air to flow from the various passages to the priming pump

Question 24

What is the function of the intake screens?

Answer 24

They block debris from entering the pump.
The die-cast screens are made of zinc to counteract electrolysis. They inhibit corrosion of crucial pump components by becoming corroded sacrificially.

Question 25

What type of transmission do we have on our quantum and truck? What is the fluid capacity?

Answer 25

Allison world transmission

Question 26

What is the gross vehicle weight of the Pierce quantum engine?

Answer 26

42,740lbs

Question 27

If the temperature gage started to rise what steps would you take to prevent overheating?

Answer 27

Verify that the gauge on the pump panel is consistent with the gauge inside of the cab of the engine.
Open indirect cooling valve.
Check radiator grill for obstructions
Turn on heater in cab to help radiate heat
Direct hose stream into radiator

Question 28

What is the voltage of the battery system? What is the rated amperage of the alternator?

Answer 28

12 volts

360 Amps

Question 29

What are the functions of the Kuszmaul system on the quantum engines?

Answer 29

The Kuszmaul system is designed to trickle charge the engines batteries, the engine block heater and supply power for the air compressor both the brakes and folding steps in order to maintain air pressure.

Question 30

Name the different tests of an annual pump service test

Answer 30

Dry vacuum test
Priming test
Pressure control device test (250, 150 & 90 psi)
100% capacity test
70% capacity test
50% capacity test
Gauge test
Overload test
Tank to pump flow rate
Pump engine control interlock
Intake relief valve system test
Engine speed check

Question 31

When using the 125 GPM educator, how long will it take to empty the phone tank when flowing at 3% and 6% concentration?

Answer 31

3% 8 mins
6% 4 mins

30 gal tank

Question 32

What are the four things that can put a pump out of service and who can put the pump out of service?

Answer 32

Tires, brakes, pump, and pressure relief devices. The company officer can put the apparatus out of service.

Question 33

What are the three sources from which ACWD attains its water?

Answer 33

Hetch hetchy, South Bay aqueduct, perculation pit/ niles cone

Question 34

Identify the main sizes commonly used in the water distribution system for residential, business, and industrial Districts

Answer 34

8, 12, 18

Question 35

Pierce pressure governor discharge pressure minimum psi

Answer 35

45