Q. What makes a fire pump different from other kinds of pumps?
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A. Although Aurora fire pumps are nearly identical in appearance to their 410 and 420 horizontal split-case pumps, they differ in a few subtle ways that make them more suitable for use as Listed Fire Pumps. First, they meet the stringent requirements of NFPA Pamphlet 20, Underwriters Laboratories and Factory Mutual Research Corporation for reliability and unfailing service under the most difficult and demanding circumstances. This fact alone should speak well for Aurora’s product quality and premium design features. Fire pumps are required to produce specific flow rates (GPM) and pressures of 40 PSI or greater. Further, the above-mentioned agencies advise that the pumps should produce at least 65% of that pressure at 150% of the rated flow — and all the while operating at a 15-foot lift condition. The performance curves must be such that the shut-off head, or “churn,” is from 101% to 140% of the rated head, depending upon the agency’s definition of the term. Aurora’s fire pumps are not offered for fire pump service unless they meet all agencies’ requirements.
Beyond performance characteristics, Aurora fire pumps are scrutinized by both U.L. and F.M. for reliability and long life through analysis of their design and construction. Casing integrity, for example, must be suitable to withstand a hydrostatic test of three times the maximum operating pressure without bursting! Aurora’s compact and well-engineered design allows us to satisfy this specification with many of our 410 and 420 models. Engineering calculations for bearing life, bolt stress, shaft deflection, and shear stress must also be submitted to U.L. and F.M. and must fall within conservative limits to ensure utmost reliability. Again, the superior design of Aurora’s split-case line comes through with flying colors. Finally, after all the preliminary requirements have been met, the pump is ready for final certification testing to be witnessed by representatives from U.L. and F.M. Performance tests will require that several impeller diameters will be demonstrated satisfactorily, including the minimum and maximum, and several in between.
Q. What is the typical lead time for a fire pump?
A. The control panels can ship out in a week or two if desired, but often are held back to ship with the fire pumps. Typical lead times run 5-8 weeks from release of an order; however, Aurora has a Red-Hot Quick Ship program for their fire pumps which can produce fire pumps in three, two, or sometimes even one week! Call us for details.
Q. Is there a market for used fire pumps?
A. No. Due to the liability encountered in fire pump installations, there are not many people who would be willing to risk putting used equipment in a new system.
Q. What is the easiest way of determining pump rotation?
A. For a horizontal split-case fire pump, if you are sitting on the motor facing the fire pump, from this vantage point a pump is right-hand, or clockwise, if the suction is coming from the right and the discharge is heading toward the left. The opposite is true for left-handed, or counterclockwise rotation. The key is the vantage point when discussing this topic. Make sure both parties are viewing the pump casing from the same side.
Q. Can I get a single-phase fire pump?
A. Yes, provided that the motor HP does not exceed 15, and the job site voltage is 230 volt. The motors on these units are not currently listed for fire protection, but the control panels on the fire pumps are. Cost increases are moderate.
Q. How are engines and motors sized for fire pumps?
A. Motors and engines supplied with Aurora fire pumps are sized according to U.L., F.M. and NFPA 20 (), and are designed to operate on any point of the fire pump curve without exceeding the motor nameplate service factor, or engine size. Do not be fooled into thinking that the motors are sized only to 150% of nameplate capacity. It is not uncommon for fire pumps to operate well beyond 150% of rated capacity (for example, if there is an open hydrant or broken pipe downstream).
For more specifics, please refer to NFPA 20 () paragraph 4.7.6, UL-448 paragraph 24.8, and Factory Mutual’s Approval Standard for Split Case Fire Pumps, Class , paragraph 4.1.2. All motors and engines supplied with Aurora fire pumps are sized to the true intent of NFPA 20, U.L., and Factory Mutual.
Since fire pump motors are not expected to be running continuously, they are often sized to take advantage of a 1.15 motor service factor. So unlike domestic water or HVAC pump applications, a fire pump motor is not always sized “non-overloading” across the curve. If you do not exceed the motor 1.15 service factor, it is allowed. An exception to this is when a variable speed inverter duty electric motor is used.
Q. Can I use a flow meter loop as a substitute for a test header?
A. A flow meter loop is often practical where flowing excessive water through standard U.L. Playpipe nozzles are inconvenient; however, when using a closed flow meter loop around a fire pump, you may be testing the pumps hydraulic performance, but you are NOT testing the water supply, which is a critical component of the fire pump system. If there is an obstruction to the water supply, this will not be evident with a flow meter loop but will certainly be exposed by testing a fire pump with hoses and Playpipes. On an initial start-up of a fire pump system, we always insist on flowing water through the system to ensure the integrity of the entire system.
If a flow meter loop is returned back to the water supply — such as an above-ground water tank — then under that arrangement you will be able to test both the fire pump and the water supply. Just make sure that your flow meter is properly calibrated.
Q. I heard you no longer need a relief valve on diesel fire pumps. Is that true?
A. Not in all cases! By ‘relief valve’, we are assuming you mean “main relief valve” for the system. The answer to this question depends on the specific pump being used, as well as the specific static suction pressure at the intended installation. NFPA 20 allows for the overspeed shutdown on diesel-driven fire pumps to protect the system in event of a “runaway engine”; however, the overspeed shutdown will operate on a 10% overspeed condition. Since pressure delivered by a centrifugal fire pump is a square of the impeller speed, you need to take the product of the pump’s churn pressure multiplied by 1.21 and add this result to the highest expected suction pressure at the fire pump. If the result exceeds the pressure rating of your fittings, then you need a main relief valve. Remember to refer to the individual pump’s performance curve, which varies by manufacturer and model number. This is in accordance with NFPA 20; however, it is our recommendation to use 1.44 instead of 1.21 in the equation, since many engine overspeed safety devices operate at 120% of rated speed, not just 110%. When in doubt, use a main relief valve.
As for electric motor-driven fire pumps, NFPA is moving away from using main relief valves to protect system fittings (refer to NFPA 20 () 4.18.1.2, and 4.18.1.3). This means that you need to know the churn pressures on your fire pumps AND the maximum expected static suction pressure of your installation. Aurora has several “flat” or low churn models available. Call for details.
Q. Do I need to worry about NPSH in fire pump applications?
A. Rarely. NPSH (net positive suction head) is an important consideration in industrial applications, such as boiler feed or hot water pumps. With fire pumps, however, you are dealing with cold water, which uses all of atmospheric pressure to your advantage. Fire pumps need a “flooded suction,” where the water arrives to the pump impeller through gravity. You need this to guarantee a pump prime 100% of the time, so that when you have a fire, your pump operates! It is certainly possible to install a fire pump with a foot valve or some artificial means for priming, but there is no way to guarantee 100% that the pump will function properly when called on to operate. In many split-case double suction pumps, it only takes approximately 3% of air in the pump casing to render the pump inoperable. For that reason, you will not find a fire pump manufacturer willing to risk selling a fire pump for any installation that does not guarantee a “flooded suction” to the fire pump at all times.
Q. When will you answer more questions on this FAQ page?
A. We will add them as issues arise, but feel free to call us with your questions!
A pressure sewer system uses small-diameter pipes and grinder pumps installed at each home. The sewer lines are buried just below the frost line and follow the countours of the land ("up and down" hills or a constant grade across flat land, for example).
The grinder pump station collects all of the wastewater from the home and grinds it into slurry. The wastewater is then pumped to a wastewater treatment plant or system, a gravity manhole, a larger sewer main or to a septic system.
The design process includes the following steps:
1. Collect information: Project layout showing location of connections (scaled); contour information; discharge location
2. Sketch a proposed pipe network layout: Flow should generally always head towards the discharge; no loops
3. Create zones designations where flow changes: More pumps operating simultaneously; and where two branches connect
4. Perform hydraulic calculations. E/One Design Assistant software is available for free in the Design Center
5. Optimize the design as required
E/One offers a no-cost preliminary design service to help users evaluate the feasibility of a pressure sewer for a project. Visit the E/One Design Center for more information.
E/One recommends that combination air/vacuum valves be utilized.
Air/vacuum valves, air release valves and combination air valves prevent the concentration of air at high points within a system. This is accomplished by exhausting large quantities of air as the system is filled and by releasing pockets of air as they accumulate while the system is in operation and under pressure. Air/vacuum valves and combination air valves also prevent a potentially destructive vacuum from forming.
Air/vacuum valves should be installed at all system high points and significant changes in grade. Combination air valves should be installed at those high points where air pockets can form. Air release valves should be installed at intervals of 2,000 to 2,500 feet on all long horizontal runs that lack a clearly defined high point.
Air release stations are available from E/One. Consult your local distributor for more information.
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A grinder pump may be needed if your community has a low pressure sewer system, your home is located below grade from the sewer line and you need to pump uphill, or your home is located far away from the sewer line and connecting by a gravity sewer line is not possible.
Grinder pump are also installed to serve the basement of a home when a bathroom, kitchenette, etc is added to a home and the wastewater needs to be pumped vertically.
The life expectancy of an E/One grinder pump is difficult to pinpoint. There are many variables that contribute to the life expectancy of a grinder pump, such as: proper installation, system design, system pressure, run time, and what items go down the drain and into the pump.
E/One grinder pump have been known to last well over 20 years in some cases. The published average mean time between service calls is 10 years.
All of the wastewater in your home from toilets, showers, dishwashers, sinks, etc. empties into the grinder pump station. When the water in the tank reaches a certain level, the pump will turn on automatically and pump the wastewater to the sewer system. Most of the time, you won't even notice the pump running; it produces about the same level of noise as a washing machine and usually runs for only a few minutes.
Do not dump oil, grease, paint, strong chemicals, sand, kitty litter, etc. down your drain. Feminine products and personal/cleaning wipes should be disposed of in a garbage can. These items should not be flushed into any sewer or septic system. They can damage your pump or build up in the tank and prevent your pump from working properly.
The only items that should be going down your drains are water, regular toilet paper, and human waste. The following items should not be introduced into the grinder pump station (or any sewer system); they can damage or cause premature problems (parts wearing out) with your pump, or build up in the tank and block your pump from working properly.
Do not dump large amounts of grease, paint, strong chemicals, and avoid putting sand, kitty litter, etc. down your drain.
Feminine products and personal/cleaning wipes (even if they're marked "flushable") should be disposed of in a garbage can, not flushed. "Flushable" only means that the wipes will fit through your home's pipes, not that they will break down in water.
Refer to our Grinder Pump Owners Guide for more information about what not to flush.
The alarm on your grinder pump station will sound when the wastewater in the tank reaches a certain level ("alarm level").
An alarm may occur if a large amount of water goes into the tank and rises above the pump's alarm level, such as emptying a large whirlpool bathtub. After the pump "catches up," the alarm turns off by itself and does not turn on again. We call this a "nuisance alarm." Frequent nuisance alarms during normal water usage (showers, washing machine, etc) may indicate that the pump is having trouble "keeping up" with pumping and needs service.
A nuisance alarm may also occur after a power outage: wastewater may be above the pump’s alarm level and the pump needs a few minutes to pump down the tank to a normal level. If the alarm doesn't turn off, call for service.
An alarm will occur if the pump has stopped working and wastewater in the tank rises above the pump's alarm level. Discontinue water use to avoid causing a backup or overflow. Never silence the alarm and continue using water if your pump is not working; you will cause a backup or overflow and possibly damage the pump.
If the alarm turns off after a few minutes and does not turn on again, the grinder pump should be OK. Check regularly to ensure that the grinder pump is operating and the alarm is not on.
If the alarm turns on and off repeatedly or turns on and stays on, call an authorized service center for service. Discontinue water use to avoid causing a backup or overflow.
Look on your alarm panel for a service sticker with a number. If no service sticker is on the panel, call our Service Link (USA) at 1-866-539- to find a service center near you.
E/One grinder pumps come with an alarm panel. If your grinder pump is working properly, you shouldn't notice it at all — the pump will turn on as needed and pump down the tank; its noise level is similar to that of a washing machine. The pump will turn off after a few minutes.
If your pump stops working, the alarm panel's red light will blink and a buzzer will sound. If the alarm doesn't turn off after a few minutes, call for service. Look on your panel box for our Service Link number.
Drain cleaner can be used, but choose carefully: use a household (not industrial strength) drain cleaner and follow the instructions on the bottle. Then, flush enough water to ensure that the pump turns on so the pump isn't sitting in the chemical for any period of time.
Refer to the ingredients or MSDS information for the drain cleaner. Please contact us if you need additional information.
Yes, you can rinse paint brushes, but get off as much paint as you can before you start rinsing brushes. This is a good idea for your pipes as much as it is for your grinder pump.
Never disposed of unused paint down the drain -- paint of any kind should never be introduced into a sewer system of any kind per the EPA.
Sizing and selecting an appropriate grinder pump station is important for ensuring long life of the pump. The following are basic guidelines for station sizing. Visit the Design Center or contact E/One if you need further assistance.
E/One manufactures one grinder pump that is available with a number of different tank sizes. Station sizing takes many factors into consideration including:
- Residential or non-residential/commercial application
- Expected total daily flow (not the number of water-using fixtures)
- Regulatory guidelines (local, regional, or national)
The most common application for pressure sewer systems is single-family, residential applications. A grinder pump station is located at each home and is sized to accommodate the home. The most popular residential E/One grinder pump station is the DH071.
Other configurations are available. Contact your local distributor for help choosing what is best for your region and need.
Sizing E/One grinder pump stations for non-residential and commercial applications is more complex. Commercial grinder pump station sizing considers many of the same factors as residential appliations, especially total daily flow. E/One typically uses known/estimated flow from the Table H 201.1 (4) from UPC Appendix H. This estimates flow based on intended use of the site and the intended occupancy. E/One avoids using fixture counts because, in our experience, flow is typically overestimated and results in an oversized system.
Constant, predictable pump output is the foundation for proper hydraulic design. It enables the engineer to minimize retention time, pump wear and deep scouring action at effective levels. E/One's semi-positive displacement (SPD) grinder pump was developed for wastewater applications. Pumps & Systems magazine featured an article about SPD pumps for pressure sewer systems that compares SPD and centrifugal pumps.
E/One offers grinder pump stations for residential (simplex stations) and light commercial (duplex through quadplex stations) applications. All grinder pump stations use the 1 hp Extreme Series pump. Visit the Product Catalog for the available tank capacities, tank materials and GPD ratings.
E/One's grinder pump lends itself to complex system designs because of its nearly vertical pump curve and the resulting nearly identical flow rate allows a wide variety of discharge heads. The predictable flows of the SPD pumps provide tolerance of widely varying system pressures.
SPD grinder pumps are crucial to the success operation of a pressure sewer system. The performance characteristics of SPD pumps assist in maintaining a sewer network free from blockages. When deposition of solids occurs, tending to block the pipe, centrifugal pumps will move toward shut off, reducing flow and velocity and increasing the tendency to block the pipe. SPD pumps constantly scour the lines to prevent buildup because flow is maintained although pressure or head increased, effectively scouring the pipe.
A grinder pump station that is too tall shouldn't be a problem other than aesthetics and possibly being in the way. The station can be shortened, but contact E/One or your local distributor for proper instructions.
A grinder pump station that is too short can allow infiltration into the tank. If this happens, the pump will run much more often than necessary, possibly introduce sand, stones or other debris, and cause problems (or a shorter life) for the pump. In this case, the E/One Extender or another E/One accessway extension is needed. Contact E/One or your local distributor to determine what extension you need.
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