Common Types of Pumps

Booster Pumps

Put simply, these are pumps that add pressure to the existing pressure of a system. Booster pumps work in conjunction with other pumps. They are designed to "boost" the performance of an existing water system. Booster pumps are often centrifugal pumps, relying on one or more impellers to increase fluid pressure. These are generally used where higher pressures are required or where a pressure differential is needed, such as for filter flushing or fertilizer injection.

Centrifugal Pump

Centrifugal pumps use the centrifugal force of an impeller to “sling” the water through the pump, efficiently increasing pressure. Using a rotating impeller, a centrifugal pump draws water into the center of the impeller and then “slings” it out again, which increases the speed of the liquid and creates pressure to move the liquid through a pipe or hose. Centrifugal pumps are most often used for turf irrigation and pressure-boosting applications, where the pump is used intermittently.

Submersible Pump

These pumps operate just as the name describes. Submersibles are at least partially, and sometimes fully, submerged in the water. The water keeps the pump motor cool, allowing it to operate for long periods of time, sometimes constantly. Submersibles are usually recommended for water features, dewatering, and applications when the pump can be in constant use. Well pumps, used in domestic water and irrigation applications, can be centrifugal (shallow well) or submersible (deep well).

Water Transfer Pump

A water transfer pump is not usually considered an irrigation pump. These are utility pumps that move water from one location to another through hoses. They can handle everything from light aquarium applications to heavy dewatering. The most common applications include draining pools, spas, and hot tubs. It is important to recognize that these do not create pressure or flow as the pumps above do. A typical tell-tale sign that a pump is a water transfer pump is when the flow measurement, GPH (gallons per hour), is used in the pump specifications. Irrigation pumps will most often use GPM (gallons per minute) as their flow measurement. 

Pump Terms & Vocabulary

Cavitation: When bubbles or voids form within fluid because the pressure quickly drops below the vapor pressure. The bubbles then collapse, causing small shock waves that can damage components of the pump over time. When these pressure waves punch holes into parts and components it is called "pitting”. Cavitation sounds like tiny rocks are in the pump. Here is a video from Munro on cavitation: https://youtu.be/BOgUyXVAGu8 

Cycling: If the pressure is low in your system, your pump is signaled to turn on. If the pressure is too high, the pump is signaled to turn off. If you have too much water pumping through your system then water will return to the pump causing it to turn off. When pressure stabilizes again, the pump will turn back on. This will quickly burn out your pump! Cycling typically occurs when your pump provides more flow than your system uses. In this case, you will want to provide a bypass back to your water source to prevent water from returning to the pump. 

Elevation Change: If your pump sits above your water source, you will need to account for the amount of suction lift (in feet) that your pump will have to execute. Suction lift is the vertical distance from your pump to the water level. If your pump is below the area that you plan to water, then you must measure the distance from your pump to the highest point that water will have to reach. Then add these numbers together for your total elevation change. 

Friction Loss: This occurs as water moves through tubing, pipes, and fittings. When friction loss occurs, pressure is reduced. How do you determine friction loss? With the Friction Loss Calculator!

GPH: Gallons Per Hour (the measurement typically used with water transfer pumps)

GPM: Gallons Per Minute (the measurement typically used with irrigation pumps)

Horsepower (HP): Horsepower is what drives the motor to operate the pump. More horsepower means more volume (flow) and pressure (PSI), although it is not what you use to select the proper pump size. While oversizing is not recommended, you can expect a larger system to require a larger pump with more horsepower. Most pumps are designed to push water, so when lifting water also, horsepower and impeller size (and shape) may play a role in pump selection.

Loss of Prime:  The water inside an above-ground pump has been lost with water in the piping between the pump and the well. Here is a video from Munro on loss of prime:: https://youtu.be/f3VcGUMUm0o 

Power Source: Since a pump generally requires a motor to operate it, you must have a source of power that matches the pump; AC (electrical), DC (battery), gas/fuel, or possibly solar. The pumps we currently sell, at Drip Depot, are electrically powered, single-phase 110V or 220V AC with the option of 3-phase for some of the larger pumps. Taking this into account, you must have a power source nearby.

Specific Gravity (SG): The ratio of the density of a substance to the density of a standard, usually water for a liquid or solid , and air for a gas. The specific gravity of water is 1.

Total Dynamic Head (TDH): The vertical distance that liquid travels (in feet) plus(+) the friction loss from the pipe (in feet).

Water Horsepower (WHP):  The minimum power required to run a pump.

Gathering Info to Size a Pump

Often, customers are under the impression that a pump needs to be selected first, before setting up and designing their system. This is actually not the case. For best results, the pump needs to be fitted to the specific system or application in which it will be used. This means all details from the mainline down to the emitters have to be decided on.

“Work from the emitters back” quite literally can be applied like this:

The first thing to decide: What watering devices will you be using, and how many?

Next, as with any system, use the run length and flow rate demand of the emitters to decide the mainline material (poly, LayFlat, PVC, Oval Hose) and the size. 

Know the elevation changes. There is simply no way around this. Should you need help determining the vertical foot distance, knowing the horizontal distance and the grade of the slope can be used to determine vertical rise.

You can then use friction loss charts or tools to calculate the appropriate pressure loss based on mainline material, size, length, and flow rate. Pressure Loss Calculator 

Last, but not least, you can use the PSI requirement of the watering devices selected to determine the optimal pressure to shoot for.

Step 1 - Calculate Gallons Per Minute

Add up the number of watering devices and multiply by the flow rate(s). If below 1 GPM (60 GPH) the application may need a bypass or return system built to redirect the excess water. Or, you may need to consider if a pump is appropriate for such a small-scale application.

Step 2 - Account For Elevation

Determine the vertical foot distance between the water level and the pump. For submersible pumps, this value will be zero (0). Determine the vertical foot distance between the pump and the highest point in the system.

If the pump sits above the water level it is pumping from, the suction lift is considered in the calculation. The suction lift is the vertical distance between the water level and the pump inlet. Most irrigation pumps are designed to push, not pull, water and are often not designed to lift water more than 25 feet. Furthermore, if the area you are taking the water to is higher than the location of the pump, you must calculate the vertical distance from the pump inlet to the highest point in your system.

If it is impossible to measure vertical distance (A to C), then you can measure the static pressure in PSI with a pressure gauge, and convert it to feet by multiplying the PSI x 2.31 to get feet of head (vertical distance). You will need to install a pressure gauge on the bottom end of your supply line, fill the supply line with water from the top end and measure with a gauge. Then convert using the formula mentioned earlier.

Alternative methods will involve thinking back to your high school mathematics days. You can figure out the side dimensions of a triangle when you have at least one side measurement and one angle degree (not the right angle) using trigonometry - sine, cosine, and tangent formulas. Or, if you know two side dimensions use the Pythagorean theorem, a² + b² = c², where c is the hypotenuse (longest side).

Step 3 - Calculate Friction Loss

Using material, length, size, and flow rate to the system, calculate the estimated pressure (PSI) loss that will occur in the mainline. Use the pressure loss calculator on the website(Pressure Loss Calculator) for poly tubing up to 1”. Our layflat item pages have a Pressure Loss PDF, and Hunter Industries features PVC pressure loss charts.  

Once the PSI loss is determined, multiply by 2.31 to convert PSI to feet.

As water moves through the pipes and fittings in your irrigation system, friction loss occurs, which reduces pressure. Most manufacturers of tubing and pipe will have a friction loss chart to help with this. Choosing the optimal pipe size is relevant to an efficient operating system. A common misconception is a smaller pipe size will increase pressure. The truth is, in fact, the opposite. You must push water through a smaller pipe faster to maintain the outflow needed, which increases pressure loss. In fluid motion, it is best to keep velocity to no more than five feet per second. 

Here is a sample of a Friction Loss Table:

Step 4 - Determine Required Pressure

All watering devices have an operating pressure that must be met in order to achieve the expected operation. Determine what operating pressure would be optimal for the specific watering devices used. Once determined, multiply the PSI required by 2.31 to convert to feet.

Step 5 - Calculate TDH (Total Dynamic Head)

Add up all foot measurements from steps 2-4

Step 6 - Confirm GPM & TDH Measurements

Use the pump chart to plot the points on the graph

Plotting Data Points on the Pump Chart

Use the pump chart to plot your data points on the X and Y axis

X axis = Flow rate (GPM)

Y axis = Total Head (Feet/TDH)

How to use this chart:

Plot the points on the graph and look for pump curve lines (performance). Ideally, you want to be close to the curve line without touching or going above it or too far below it. 

If the data point is right on a performance line, it means the pump will have to operate at absolute max capacity in order to supply the system. This is not ideal, as it can cause the pump to fail prematurely. 

A data point above the line will likely over-tax the pump and is not a good choice.

If the data point is slightly under the line, this is the most optimal use of the pump. 

A data point significantly under the line means the pump is overpowered for the application and may be subject to cycling due to excess flow and power. Cycling can cause damage and, ultimately, premature failure or burnout of the pump.

Drip Depot Pump Curve Chart: 

Munro Pond Pump Curve Chart:

Outliers & Ends of the Spectrum

Extremes on either end of the spectrum are not ideal!

Low Flow Demand: Low flow demand can be mitigated by building a bypass for excess water provided by the pump. This allows water not being used by the system to continue to flow and be returned back to the water tank or source the pump is pulling from. Allowing the extra water to be redirected prevents the cycling of the pump. (Repeated turning on/off of a pump during a watering cycle)

Low PSI Demand: Low PSI demand from the system can be mitigated by adding a pressure regulator. Special attention should be paid to the flow rating of the pressure regulator, as you will need to match the GPM to the range of the regulator.

High Flow Demand: This is normally not a hard issue to mitigate. However, rare situations may occur where the flow (GPM) available from the pump at the TDH needed is insufficient. In cases like this, simply zoning the system would be recommended

High PSI Demand: This can’t really be mitigated. The required pressure is imperative for the proper operation of watering devices. Using a lower PSI or the lowest acceptable PSI in the operating range of the water devices is going to be the best option. Also looking for ways to reduce pressure loss and eliminate any unnecessary elevation. Ultimately, you need to find a way to cut down the TDH. 

Pump Automation- Startbox vs. Smartbox & Variations

Startbox - Standard (The old Stand-by)

This pump start relay provides “pilot-duty” operation for all electrically driven pump equipment. Has a 40 amp relay to work equally well with single phase 3/4 hp to 5 hp. For use with controllers with a .36 amp signal or stronger. Works with any residential turf irrigation pump – available in 24v, 110v, and 220v coils

StartBox – Reduced Incoming Amperage

This pump start relay accepts a low amperage start signal from the controller to provide all of the benefits of the standard StartBox, even though signal amperage is reduced. It works with any reliable brand of 24v lawn controller – including 2-wire systems and those that provide less than .35 amps for a pump start. Voltage specific – 110v or 220v – to match the line voltage of the pump. A single unit eliminates the need for secondary transformers to be installed with decoders.

Startbox with REA & Float Switch (Liquid Level Control Box)

The water level control box is a simple, cost-effective control for applications when the water level is variable. The Munro water level control provides pilot duty operation when thermal overload protection is present, for example, submersible water feature pumps or dewatering pumps. Used at any place power can be interrupted, this control transforms all outbound voltage to a low, safe, 24v. Low external voltage is especially important when external sensors or switches are used, such as the float switch included with this control box.

Smartbox - Standard

A great option for pump start and pump protection in one. Includes a preset pressure sensor that alerts the control system of potential pump damage due to loss of prime or run-dry. Additionally, provides personal protection, as all external devices are powered at a reduced 24 volts. (Low risk of line voltage harming people or pets.) Has a 40 amp relay to work equally well with single phase 3/4 hp to 5 hp. Available in 24v, 110v, 220v coils. Works with any residential turf irrigation pump.

Smartbox - Reduced Incoming Amperage

Identical to the operation of the original Smartbox, but accepts a low amperage start/stop signal – to provide all of the benefits of the standard SmartBox, including loss of prime and run-dry protection, even when signal amperage is reduced. Works with any brand, any style of 24v lawn controller. For use with lawn controllers that provide less than .35 amps for pump start signaling. Run-dry and dead-head protection.

Smartbox - Thermal Protection

 but this SmartBox variation not only protects the pump motor from run-dry or loss of prime, it also protects from damage due to over-amping. Provides the pump motor with thermal overload protection, even when the motor itself does not. Auto-resets upon cool-down. Available 3 hp and above.

Smartbox w/ Pressure and Flow Start

Grab your hose and water your plants or wash down the driveway, the pump will automatically run on your demand for water. No need for a pressure tank! On-demand controls utilize flow and pressure to detect water demand. Start and stop up to a 2HP pump. Connect the pressure and flow switch to any pump discharge and the Pressure Start Control Box will turn the pump on and off -  Low pressure and dead-head protection. Choose from a 110-volt model or a 220-volt model.

Smartbox w/ Retry Switch

The same benefits as the original Smartbox includes system shut-down from low pressure or high-temperature sensor, an adjustable 10-minute timer will automatically restart pump to check if the problem has been resolved.

How to decide which Startbox or Smartbox to use? (Part 1)

To begin, what is the desired function?

How to decide which Startbox or Smartbox to use? (Part 2)

Start Box Simple On/Off Functionality: (Standard)

Startbox (Standard)

Specifications: Signal Voltage = 24 V, Line Voltage: 110V, 220V, 40 Amp Relay

Compatibility: Controllers w/ .36+ Amps, All single phase ¾ HP - 5 HP pumps

Features & Applications: Pump start relay for residential turf irrigation pumps

StartboxOperation Based on Water Levels: Liquid Level Control

Startbox w/ REA & Float Switch

Specifications: Signal Voltage = 24 V, Line Voltage: 110V, 220V

Compatibility: Controllers w/ .36+ Amps, All single phase ¾ HP - 5 HP pumps

Features & Applications: Pump start relay with water level control for variable water level applications. Install anywhere power can be interrupted. Pump Up, Pump Down Feature

Startbox Low Incoming Amperage & 2-Wire Decoder System: Reduced Incoming Amperage Control

Startbox for Reduced Incoming Amperage 

Specifications: Signal Voltage = 24 V, Line Voltage: 110V, Pressure & Temperature sensor included 

Compatibility: Any 24V controller that provides .35 Amps or less, 2-wire decoder system 

Features & Applications: Pump start relay that accepts low amperage, start/stop signal, Compatible with 2-wire decoder system

Smartbox On/Off functionality with Pump Protection: (Standard)

Smartbox (Standard)

Specifications: Signal Voltage = 24 V, 110V, 220V, 40 Amp Relay, 20 PSI pressure sensor included 

Compatibility: Controllers w/ .36+ Amps, Any residential turf pump 

Features & Applications: Pump start relay and pump protection. Will alert the control system of issues, such as, loss of prime or run-dry that may cause pump damage. Provides personal protection against higher line voltage contact as all external devices operate at 24 volts

Smartbox Thermal Protection

Specifications: Signal Voltage = 24 V, 110V, 220V, Pressure sensor included 

Compatibility: Controllers w/ .36+ Amps, All single phase ¾ HP - 5 HP pumps 

Features & Applications: Pump start with protection against over-amping with thermal protection, auto resets once motor cools down

Smartbox w/ Retry Switch

Specifications: Signal Voltage = 24 V, 20 PSI Pressure & Temperature sensor included 

Compatibility: Controllers w/ .36+ Amps, All single phase ¾ HP - 5 HP pumps 

Features & Applications: Pump start relay with retry timer that automatically tries to restart pump upon shutdown protection mode

SmartBox Operation Based on Water Levels: Liquid Level Control

Smartbox w/ Pressure & Flow Start (220V)

Specifications: Signal Voltage = 24 V, Line Voltage: 110V, 220V

Compatibility: Controllers w/ .36+ Amps, Up to 2 HP pump 

Features & Applications: Pump start relay with pressure start. No pressure tank required

SmartBox Low Incoming Amperage & 2-Wire Decoder System: Reduced Incoming Amperage Control

Smartbox for Reduced Incoming Amperage 

Specifications: Signal Voltage = 24 V, Line Voltage: 110V, 220V, Pressure & Temperature sensor included 

Compatibility: Any 24V controller that provides .35 Amps or less, 2-wire decoder system 

Features & Applications: Pump start relay that accepts low amperage, start/stop signal, Compatible with 2-wire decoder system

Pump Accessories

Choosing a pump can be a very difficult process, especially when using for an irrigation system. To make matters even more complicated, installing a pump typically requires an assortment of parts and accessories that aren’t common knowledge for the average DIYer.

Standard Components

Basket Strainer: This can be used with centrifugal pumps to filter out large debris. If pumping from a clean water source, a basket strainer is typically more effective than a y-strainer. These basket strainers only work when pumping from an open water source.

Foot Valve: A foot valve is a simple check valve that holds water in the intake pipe when the pump is turned off, so the pump maintains its prime and the backflow of water is prevented. This helps to keep centrifugal pumps primed. Foot valves are usually installed at the beginning of the intake pipe/suction line.

End-suction centrifugal and jet pumps should have a foot valve installed on the intake pipe/suction line. Submersible pumps typically have built-in foot valves.

Inlet Screen: Provides an extra level of filtration prior to liquid/water being introduced to the suction line of a pump. Typically for dirty water sources. Usually necessary when pulling from a lake, pond, or river.

Suction Hose/Discharge Hose: A hose used for suction or discharge that is able to withstand vacuum conditions. PVC or rubber hoses are commonly used. 

A suction hose is used on the suction side of the pump to draw the water into the pump. Suction hoses must be non-collapsible and are usually reinforced rubber or PVC. Sizing the hose is crucial to optimal operation. It is recommended to maintain a straight length run of the hose or pipe at least 5 - 10 times the diameter of the hose or pipe between the pump and any other component, such as elbow fittings or the foot valve. So a 2" suction pipe would need at least 10 - 20 inches of straight pipe length on the suction side. Also, never reduce the pipe size on the suction side, use the same or one size larger hose or pipe as the inlet connection. Provide proper support for the suction hose or pipe so it does not put any strain on the pump itself. 

The discharge hose is connected to the pump outlet providing the access point for your irrigation system. Several hose or pipe options are available for the discharge side of the pump.  The choice often depends on your irrigation application. In an agriculture application, someone might choose Layflat or poly for this, whereas, a lawn sprinkler system, most often PVC or PE, sprinkler hose is used. 

Y-Strainer: A screen mesh inline strainer with a drain or flush port that prevents large debris from entering the pump when installed on the suction line or anywhere in a piped system to collect and flush debris easily. The Y-Strainer is normally installed horizontally with the drain port positioned downwards for easy flushing.  If installed in a vertical pipe, it should be installed with the pipe flow direction coming in from the top, flowing downward. There is a flow direction arrow on most units to ensure proper installation.

Centrifugal Standard Set-Up with Accessories

Complete Units

The Complete Pro II from Munro has everything you need in one complete package! Complete Pro II vs. Complete PRO II w/ Pressure Smartbox… What is the difference?

Basic Components included:

Check out these resources for additional pump information:

Pump FAQ and Term Glossary

Water Pump Buying Guide

Pump Sizing Worksheet

Pump Troubleshooting

Drip Depot Pump Chart Overview

Here are helpful videos by Munro: https://www.munropump.com/Resources/Videos 

Still, have questions? Please feel free to reach out to our wonderful and knowledgeable Customer Service team! Help Desk

Our supplier is also always happy to help. You may visit Munro Pumps at http://www.munropump.com