Mazzei fertilizer injectors are commercial-grade, Venturi injectors with no moving parts to wear out or break down. They work by suction, and can draw liquid fertilizer from virtually any container. The Mazzei can be plumbed on a bypass for less restriction (the preferred method), or directly into a main water line.
It is important to choose the model size carefully based on the water usage of the irrigation system. Select the injector that matches the flow rate (GPH) that your irrigation system uses. An oversized injector will not draw the fertilizer at all; an undersized injector will restrict the flow of the system. If in doubt always choose a smaller size and install on a bypass assembly. This allows you to adjust the Mazzei's flow with less restriction.
In order for the Mazzei to work properly there has to be a 25% pressure differential between the incoming pressure and the out going pressure, this will make the vacuum effect to draw fetilizer. You will need to experiment to get the dosages required, but once operating, the Mazzei is incredibly reliable and relatively maintenance free.
Mazzei Flow Chart (Venturi style)
|Mazzei Unit||Minimum Flow at 50 PSI Inlet||Fertilizer Draw with outlet pressure at|
|30 PSI (20 PSI Drop)||10 PSI (40 PSI Drop)|
|IM12VLF - 1/2" Very Low (#283)||30 GPH||2 GPH||6 GPH|
|IM12L - 1/2" Low (#287)||60 GPH||3 GPH||8 GPH|
|IM12H - 1/2" High (#384)||150 GPH||10 GPH||14 GPH|
|IM34L - 3/4" Low (#484A)||240 GPH||12 GPH||17 GPH|
|IM34H - 3/4" High (#584)||425 GPH||21 GPH||25 GPH|
|IM1L - 1" Low (#878)||750 GPH||56 GPH||75 GPH|
|IM1 - 1" (#1078)||1050 GPH||86 GPH||92 GPH|
Use the chart above to select the Mazzei model according to the gallons per hour (GPH) that your irrigation system uses, not the GPH that you have available from your water source. For example: If you are using 100 x 1 GPH emitters, your system will use 100 GPH. You would need to select the 1/2" Low Flow Injector (IM12L) which requires a minimum of 60 GPH to operate. The next largest injector (IM12H) requires a minimum flow of 150 GPH and is too large for this system.