TROUBLESHOOTING PUMP PROBLEMS

Question 1

Pump Overheating

The friction generated between the impeller and the pump water can build heat rapidly if water is not moving, which is common during overhaul. Excess heat can lead to pump damage. The engineer should monitor the pump temperature by _____ the pump piping and utilize recirculating methods and minimize RPMs to maintain a normal pump temperature.

Answer 1

Feeling

Question 2

Pump Overheating

There are several ways to recirculate water. Opening the _____ _____ discharges water into the booster tank. As it leaves the pump it is replaced with cooler water from the source (hydrant, tanker, etc.). Opening the _____ _____valve even a small amount will discharge more water into the tank. The _____ _____ can also be charged and the nozzle placed into the tank vent. Each of these recirculation methods can overflow the booster tank unless the booster tank is the water supply source. If the water supply is ample and unused hose line can be _____ just enough to keep the water moving.

Answer 2

PUMP COOLER

TANK FILL

booster line

Opened

Question 3

Motor Overheating

The cooling system needs in adequate supply of coolant and unrestricted air flow through the radiator. Unusual ____ ____ and operating at high ____ can contribute to overheating. If the motor overheats on scene the engine should be removed from service. Sometimes this is not possible without affecting fire operations if it is the case reduce _____ and _____ _____ lines that are not absolutely necessary.

Answer 3

Hot weather

RPMs

RPMs

shut down

Question 4

Motor Overheating

Open the ____ ____ valve on the pump panel if this is not effective, charge the booster line and direct a small spray of water through the grill into the radiator. This should have an immediate cooling affect. Notify TSF as soon as possible. 

Answer 4

ENGINE COOLER

Question 5

CAUTION

If overheating occurs while drafting from a natural source and water spray it onto the radiator, the radiator, motor, and underside of the cab must be decontaminated as soon as possible. A thorough cleaning with _____ and _____ can limit corrosion damage.

Answer 5

soap and water

Question 6

Unable to Build Pressure

This is most commonly caused by ____ ____ ____ ____. 

Answer 6

air in the pump

Question 7

Cavitation 

This can occur one an attempt is made to pump more water than is available. It can occur when _____, from the ____ ____, when operating from a _____, or when _____ _____.

When residual pressure approaches ____ PSI and the impeller speed remains constant, the pressure at the eye of the impeller ______. is this occurs, water temperature will increase at the impeller of the eye and create water vapor. The vapor condenses as it passes through the impeller veins. This results in the characteristic “ ______ ___ ___ _____” sound. When cavitation occurs, the pump is “____ ____” from the water. If this condition is allowed to continue, serious damage can occur.

The earliest indication of cavitation is fluctuating ____.

Answer 7

Drafting

Booster tank

Hydrant

Relay pumping

0 PSI
decreases

“Pebbles in the pump”

“Running away”

PDP

Question 8

Cavitation

Always pay attention to the gauges on the pump panel. Keep residual pressure at ____ ____ or more when being supplied from a hydrant or other apparatus. Whenever an increase in RPMs does not result in corresponding increase in ____, you have maximized your water supply. Any further attempt to increase pressure will result in ______. Governors will detect cavitation and reduce the motor speed to idle when it occurs.

Answer 8

10 PSI

PDP

cavitation

Question 9

Critical Velocity

Water flowing through a hose has a maximum velocity called ____ ____. At this point any effort to increase velocity (by increasing PDP) creates turbulence in the stream and the result is a loss of ____ ____ and ____. Critical velocity can lead to pump ____ and reduced volume from the nozzle.

Answer 9

Critical velocity

Stream reach and integrity

Cavitation