Rainbird MPR nozzles are a type of sprinkler nozzle made by Rainbird corporation specifically designed for low precipitation rate watering. MPR stands for Matched Precipitation Rate, indicating that these nozzles are engineered to evenly distribute water across the landscape. The Rainbird MPR nozzles come in several spray patterns and flow rates to accommodate different watering needs.
Some of the key features and benefits of Rainbird MPR nozzles include:
- Low precipitation rates from 0.4-1.6 inches per hour
- Even water distribution and matched precipitation rates
- Interchangeable nozzles with multiple spray patterns
- Water conserving and efficient
- Durable construction for long life
Rainbird MPR nozzles are ideally suited for watering shrubs, flower beds, groundcover areas and lawns. By providing a lower application rate over a longer period, they allow the soil to adequately absorb water and avoid runoff. This helps conserve water while still meeting the plants’ irrigation needs.
MPR Nozzle Design and Technology
The Rainbird MPR nozzles utilize patented technology to achieve matched precipitation rates across the entire spray pattern. The nozzles have a specially designed reversing nozzle that breaks up the water stream into fine droplets.
As the nozzle reverses direction, it maintains the same droplet size which results in even coverage. Most standard fixed spray nozzles have a hot spot directly in front of the nozzle and uneven distribution at the edges. MPR nozzles have consistent precipitation across the entire diameter of the spray.
The table below shows the features of MPR nozzle design:
MPR Nozzle Design Feature | Benefit |
---|---|
Reversing nozzle mechanism | Maintains consistent droplet size for even distribution |
Preset matched precipitation rates | Ensures uniform application based on flow rate |
Multiple trajectory options | Allows adaptability for different watering needs |
Durable heavy-duty construction | Withstands crushing and thread damage |
The combination of these features allows MPR nozzles to efficiently irrigate landscaped areas with minimal runoff or overspray.
MPR Nozzle Precipitation Rates
The Rainbird MPR nozzles are available in several matched precipitation rate options:
- MPR-10 – 0.4 inches per hour
- MPR-15 – 0.6 inches per hour
- MPR-20 – 0.8 inches per hour
- MPR-25 – 1.0 inches per hour
- MPR-30 – 1.2 inches per hour
- MPR-35 – 1.6 inches per hour
The precipitation rate refers to how much water is applied per hour when operating at the recommended pressure. Lower precipitation rates allow for better absorption into the soil.
Most irrigation experts recommend choosing nozzles with precipitation rates between 0.4-1.0 inches per hour for shrubs and flower beds. The rates between 1.2-1.6 inches per hour work well for lawns.
Selecting the proper precipitation rate ensures adequate watering without runoff or under-watering. It also allows for different plant types to be watered on the same zone.
Precipitation Rate Formulas
The precipitation rate of a nozzle is based on the flow rate and spray pattern diameter:
Precipitation Rate (in/hr) = Flow Rate (GPM) / Spray Diameter Squared (ft) x 0.623
Flow Rate (GPM) = Precipitation Rate (in/hr) x Spray Diameter Squared (ft) / 0.623
Knowing these formulas allows you to adjust the precipitation rate by changing the nozzle size or flow rate.
MPR Nozzle Trajectories and Spray Patterns
Rainbird MPR nozzles are available in several spray trajectories ranging from 5 feet up to 15 feet diameter. Typical spray patterns include:
- 10′ Full Circle
- 10′ Half Circle
- 15′ Full Circle
- 15′ Half Circle
- Strip Sprays (5′ – 15′)
- Quarter Circle Sprays
The most common trajectories used are the 10′ and 15′ full circle. Quarter circle and strip sprays are used for irregular shaped areas.
The spray pattern determines how far the water is thrown and the overall coverage area. Larger patterns are chosen for broader coverage and smaller patterns for precise confined space watering.
Proper spray pattern selection ensures complete coverage without overspray onto sidewalks, walls and other non-landscaped areas.
Nozzle Trajectory Formulas
The nozzle spray distance is based on the operating pressure and trajectory angle according to these formulas:
Spray Distance (ft) = 0.8 x (Operating Pressure (PSI) / Trajectory Angle)
Trajectory Angle = 0.8 x Operating Pressure (PSI) / Spray Distance (ft)
Increasing the pressure produces a longer spray distance while lowering the pressure shortens the throw.
MPR Nozzle Installation
Rainbird MPR nozzles are designed as direct retrofit replacements for standard fixed spray nozzles. They screw into any female threaded sprinkler head or riser.
Typical steps for installing MPR nozzles:
- Turn off the water to the irrigation system and relieve pressure from the lines.
- Unscrew the existing nozzle from the riser using pliers or a 9/16″ socket.
- Choose the MPR nozzle with the desired precipitation rate, trajectory and spray pattern.
- Apply a small amount of thread sealant to the threads.
- Screw in the MPR nozzle by hand until snug.
- Turn the water back on slowly and check for leaks.
- Make any adjustments to the arc alignment as needed.
MPR nozzles should be installed using the manufacturer’s recommended operating pressure to achieve the correct precipitation rate and spray pattern.
Spacing MPR Nozzles
Proper spacing is also important for full head-to-head coverage when installing MPR nozzles. Recommended spacing is 50-70% of the spray diameter.
For example, nozzles with a 10′ spray pattern should be spaced 5-7 feet apart. Wider spacing may result in dry spots between heads. Closer spacing causes overspray and wastes water.
Adjusting the spacing appropriately for the spray pattern is key to maximizing the efficiency of the nozzles.
Using MPR Nozzles to Conserve Water
Switching to Rainbird MPR nozzles from standard fixed spray nozzles can significantly reduce water usage in landscape irrigation.
Some of the water saving benefits of MPR nozzles include:
- Lower precipitation rates prevent runoff and waste.
- Matched precipitation results in more uniform coverage.
- Less overspray wastes less water in unintended areas.
- Smaller water droplets have less evaporation loss.
- Lower GPM nozzles reduce the overall water volume.
According to Rainbird, MPR nozzles use up to 50% less water compared to conventional spray heads. Much of these water savings come from the matched precipitation rates that prevent overwatering of areas closest to the sprinkler.
Many water utilities and municipalities now offer rebates and incentives to switch to water-efficient nozzles like the MPR models. The long-term water savings can provide a quick return on investment in replacing nozzles.
Water Conservation Guidelines with MPR Nozzles
To maximize water conservation with MPR nozzles, these best practices should be followed:
- Use lower precipitation rate nozzles for shrub and flower beds.
- Choose nozzles with spray patterns that avoid hardscapes and impermeable areas.
- Install pressure regulators to operate nozzles at optimal pressures.
- Inspect and adjust nozzles regularly for optimum performance.
- Group plants with similar watering needs into zones.
- Shorten watering times with lower precipitation rates.
- Water early in the morning or evening to reduce evaporation.
Proper programming and scheduling of the irrigation controller is also essential to avoid overwatering with the MPR nozzles. Soil moisture sensors and weather-based controllers can further enhance water savings.
Types of Rainbird MPR Nozzles
Rainbird offers several different versions and models of MPR nozzles for various applications:
MP1000 Series
The MP1000 series are the standard MPR nozzles for watering most lawn and landscape areas. They feature VisiFlo colors for easy identification. MP1000 nozzles have a heavy-duty construction and the reversing mechanism for matched precipitation. Flows range from 3.5 GPM down to 0.5 GPM.
MP Rotator Series
MP Rotator nozzles provide slower, more uniform water application through a rotating multi-stream spray pattern. Rotating streams help avoid dry spots. MP Rotators are available from the MPR-25 rate on up. They excel at watering turfgrass.
MP Corner Series
MP Corner nozzles are designed to provide complete coverage in 90 degree corner areas with no overspray. The spray pattern rotates 90 degrees. Flow rates range from 0.5 to 1.5 GPM.
MP Strip Series
MP Strip nozzles feature an elongated spray pattern that stretches up to 15 feet long for watering narrow spaces and borders. Spray diameters are fixed from 5′ to 15′. Flows range from 0.5 to 2.0 GPM.
MPEZ Series
The MPEZ nozzles are high uniformity MPR nozzles for consistent water coverage across the entire diameter. They utilize extra-fine atomizing streams to fill in the spray pattern. Fixed spray arcs from 40 to 360 degrees are available.
Troubleshooting Rainbird MPR Nozzles
Like all sprinkler nozzles, MPR nozzles may occasionally experience problems that affect their performance. Common troubleshooting issues include:
Leaking Nozzle
A leaking nozzle is usually caused by loose connections or inadequate thread sealant. Tighten the nozzle an extra 1/4 to 1/2 turn after hand tightening. Also inspect the o-ring for damage. Replace o-rings on a regular basis.
Uneven Watering Pattern
An uneven spray pattern can result from low or high water pressure or a damaged nozzle. Verify the pressure is within the recommended range. Inspect nozzles for debris obstructions or wear in the reversals mechanism. Replace nozzles showing uneven streams.
Nozzle Not Reversing or Rotating
MPR and MP Rotator nozzles contain internal reversing turbines. Debris or hard water buildup can stop the turbine from moving. Disassemble the nozzle to clean the turbine of buildup so it moves freely. Replace nozzles where the turbine does not spin.
Short Spray Distance
Insufficient spray distance is normally caused by low water pressure. increasing the pressure may require adjusting the irrigation valve flow control. Check for undersized pipes causing high friction loss. Consider using nozzles with a lower trajectory.
Water Draining from Head After Shut Off
This issue is referred to as “drainage” and results from a leaking valve seat or debris holding the valve open. To fix, disassemble the valve and clean the diaphragm and seat. Replace worn valves or valve seats as needed to eliminate drainage. Consider installing valve seals.
Conclusion
Rainbird MPR nozzles represent a major innovation in landscape irrigation efficiency and precision. Their matched precipitation rates result in uniform coverage while using far less water compared to conventional spray nozzles.
The variety of flow rates, trajectories and spray patterns allow the nozzles to be highly adaptable to any watering zone. And the interchangeable nozzles make retrofitting existing systems simple.
Water managers and irrigation professionals consider MPR technology to be integral to sustainable landscape watering. The long-term cost savings combined with their superior performance make Rainbird MPR nozzles an ideal choice for both residential and commercial irrigation systems.