The Walling Company of Iowa


Pump FAQs

Fire Pump FAQs

Trouble Shooting FAQs


What are Air-Operated Double Diaphragm pumps and how might I be able to use them?

Air Operated Double Diaphragm (AODD) pumps do jobs that centrifugal pumps and positive displacement gear and lobe pumps won't do:  1.  AODD's pump gently and will not shear or crush the material being pumped.  2.  AODD's will pump solids without becoming plugged.  3.  AODD's will develop suction from a dry prime.  4.  AODD's can run dry without harm to the pump.  Ask us about our AODD pumps by Warren Rupp, Nomad (JDA Global) and Wilfley.  We offer the broadest selection of air driven pump models to handle your most difficult pumping situation.  Whether you are pumping harsh chemicals or food and drugs for human consumption, or clear fluids, fluids that contain line size solids, slurries, or fluids with entrained air or gases we have the pump for you. Compressed air is an expensive utility.  Ask us to show you the Warren Rupp AirVantage, Nomad (JDA Global), Wilfley or Warren Rupp's patented air distribution system that controls the volume of air driving our diaphragms even as your pumping conditions change.


What are Centrifugal pumps and how might I be able to use them?

Centrifugal pumps are used in many different industries for many different purposes. Centrifugal pumps are like water turbines in reverse. They use a motor to move an impeller, converting rotational energy into kinetic energy, pushing water through the chamber or casing. When the water enters the casing through an “eye,” it strikes the impeller where it is moved through and out of the chamber.  The exit of the water from the chamber creates pressure on the inside that is lower than that on the outside, causing more water to flow into the chamber, where it is moved by the impeller to start the cycle again.

Centrifugal pumps have numerous applications in various industries. They are used often in oil refineries and power plants. They are also the pump of choice for municipal water applications. They are used to move the general water supply from the pressure main in cases where a little or no suction lift is required.

They can also be used for boiler feed applications, wastewater management, flood protection, drainage and irrigation.

The chemical and process industries use centrifugal pumps for applications such as chemicals, paints, petrochemicals, pharmaceuticals, cellulose, hydrocarbons, food and beverage production and sugar refining.

The mining industry uses centrifugal pumps as froth pumps, separating bitumen and minerals from clay and sand. They also use them to transport solids and slurries

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What is a Fire pump?

A fire pump is a part of a fire sprinkler system's water supply and powered by electric, diesel or steam. The pump intake is either connected to the public underground water supply piping, or a static water source (e.g., tank, reservoir, lake). The pump provides water flow at a higher pressure to the sprinkler system risers and hose standpipes. A fire pump is tested and listed for its use specifically for fire service by a third-party testing and listing agency, such as UL or FM Global. The main code that governs fire pump installations in North America is the National Fire Protection Association's 


When is a fire pump bearing too hot?

The maximum operating temperature for a ball bearing in a pump is the result of a number of factors, not limited to, but including some or all of the following:

  1. Operating speed

  2. Shaft loading

  3. Type of lubrication

  4. Amount of lubricant in the bearing

  5. Pump alignment

  6. Pumping temperature

  7. Ambient temperature

  8. Bearing fit

  9. Continuous or on-off service

  10. Location of the pump duty point on the performance curve

It is important to define where the bearing temperature is taken.  The temperature at the bearing surface will be higher than at the outside surface of the bearing cap, possibly 10 to 15 degrees F difference.  For the following, we define temperature as that taken at the bearing cap surface.

It is our position that an operating temperature at the bearing cap not exceed 175 degrees F.  This temperature would not be excessive as long as the temperature has leveled out and not still rising.  Above that point, temperatures up to 200 degrees F might still be satisfactory, but we would d recommend further investigation to determine the cause of the higher bearing operating temperature.   

Over lubrication of bearings should be avoided as it may result in overheating and possible bearing failure.  Under normal applications, adequate lubrication is assured if the amount of grease is maintained at 1/3 to 1/2 the capacity of the bearing and adjacent space surrounding it.


How often should I run my fire pump?

The 2011 edition of NFPA 25  8.3 (Testing)  Diesel engine- driven fire pumps shall be operated weekly.  The diesel pump shall run a minimum of 30 minutes.

Donald Corporation says that minimum run time must be done in order to bring the engine driver up to operating temperature.   Shorter duration runs are harmful to the engine over time.  Electric motor-driven fire pumps shall be operated monthly.

A.  More frequent testing might need to be considered in areas susceptible to lightning.

The Walling Company recommends that electric motor -driven fire pumps still be run tested weekly.  The electric pump shall run a minimum of 10 minutes.


What should I look for when I run my fire pump?

The 2011 Edition of NFPA 25 (Testing)  The pertinent visual observations or adjustments specified in the following checklists shall be conducted while the pump is running:

(1) Pump system procedure as follows:

  • Record the system suction and discharge pressure gauge readings

  • Check the pump packing glands for slight discharge

Properly adjusted packing - It is too loose if water sprays from the stuffing box -  it is too tight if packing smokes or the gland heats excessively.

  • Adjust gland nuts if necessary

  • Check for unusual noise or vibration

  • Check packing boxes, bearings, or pump casing for overheating

  • Record the pump starting pressure

(2) Electrical system procedure as follows:

The Walling Company, an Iowa, Kansas, Missouri, Nebraska, and Western Illinois based company, says that the most important observation to make is that the casing relief valve flows pipe full when the pump is running, then completely shuts off when the pump stops.  If it doesn't flow pipe full, the pump will overheat when it runs against a pressurized sprinkler system.   Severe pump damage will result from overheating.  

  • Observe the time for the motor to accelerate to full speed

  • Record the time controller is on first step (for reduced voltage or reduced current starting)

  • Record the time pump runs after starting (for automatic stop controllers)

(3) Diesel engine system procedure as follows:

  • Observe the time for the engine to crank

  • Observe the time for the engine to reach a running speed

  • Observe the engine oil pressure gauge, speed indicator, water, and oil temperatures indicators periodically while the engine is running

  • Record any abnormalities

  • Check the heat exchanger for cooling water flow

The Walling Company recommends that you verify the operation of the engine block heater.  This can be done by touching piping to and from the block heater.  It should be warm to the touch - approximately 120 to 140 degrees F.  If block heater is not operational, severe engine damage will result.   


What is the difference in the different reduced voltage starting options for main fire pump controllers?

Please click on the link below to compare the various controller starting options. 

Reduced Voltage Starter Comparison


How often do I need to grease the fire pump, the electric driver motor, the flexible coupling or diesel driven pump driveshaft?

NFPA 25 Table 8.1.2  States that you shall lubricate pump bearings and the flexible coupling or driveshaft annually.  This is the minimum requirement.  The pump bearings should only be greased more frequently if, during weekly or monthly testing, you observe excessive noise, vibration, or heating.  If the drains in the bearing arms become plugged and stuffing box drainage submerges the bearing, bearing lubrication should be inspected and reapplied if necessary.     


How do I adjust my fire pump packing?

You adjust pump packing so that the stuffing box stays relatively cool and does not leak excessively while the pump is running.  If the packing gland starts heating the packing is too tight and the shaft sleeve and packing will be damaged.  If water pours or sprays from the stuffing box, the packing is too loose and bearing damage may result and you will definitely have a housekeeping problem.  Packing must be adjusted when the pump is running.  Gland adjusting nuts on each side of the packing gland must be adjusted evenly so that the packing gland remains concentric with the face of the stuffing box.   

Many times you are instructed to adjust packing so that the stuffing box leakage is one drip per second.  This is only a general guideline, and the most important thing to remember is that the pump must be running and then the packing should be adjusted so that the stuffing box does not overheat or leak excessively,   Stuffing box conditions vary in each installation, so adjustments are unique for each fire pump.


How do I change fire pump packing?

The best way is to remove the top case of the fire pump so you can inspect the shaft sleeves and stuffing box while changing the packing.  Isolate pump with valves and remove power from the driver.  Remove the top case and packing glands.  Remove all packing rings.  Clean out stuffing boxes with a scraper.  Clean casing parting flanges with wire wheel and replace the casing gasket.   Replace packing.  Re-install top case and packing glands.  Open isolation valves and reconnect driver to power.  Run pump and adjust packing glands.  

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How do I troubleshoot my Air-Operated Double Diaphragm pump?

Please download the Warren Rupp Troubleshooting Guide, it is a very helpful reference.

If you need further assistance, please Contact Us for further help. 


How do I troubleshoot my centrifugal pump?

Please view Centrifugal Pump Troubleshooting guide for more information.

 If you need further assistance, please Contact Us for further help.


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