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The 1-1/2" and 2" Mazzei Venturi Injectors are the heavy-duty solution for professional fertigation and chemigation on large farms, commercial nurseries, and high-volume irrigation systems. Like all Mazzei injectors, these units operate on the Venturi principle — using the pressure differential between the inlet and outlet to create a powerful vacuum that draws liquid fertilizer or other water-soluble additives directly into the irrigation stream. With no moving parts, there is nothing to wear out or break down, making these injectors exceptionally reliable and nearly maintenance-free.
These larger injectors can be plumbed directly into the main water line or, preferably, installed on a bypass assembly for greater control over suction rate and reduced restriction to the main line. Important: A complete fertigation unit requires three components — the injector body, a bypass assembly, and a suction assembly. The bypass and suction assemblies for these larger units are sold separately and are not currently available online. Please call us at 1-800-522-3747 to special-order 1-1/2" and 2" Mazzei accessories. Note: the 1" suction assembly (IM1SA) is compatible with the 1-1/2" Mazzei injector.
It is critical to select the correct injector size based on your system's flow rate in GPH — not your mainline pipe size. An oversized injector will fail to draw fertilizer; an undersized one will restrict system flow.
Specifications confirmed from official Mazzei data sheets.
| Specification | Model 1583 (1-1/2") | Model 2081 (2") |
|---|---|---|
| Inlet & Outlet Connection | 1-1/2" Male NPT | 2" Male NPT |
| Suction Port Connection | 1/2" Barbed / 1/2" Male NPT | 1-1/4" Male NPT |
| Motive Flow at 40 PSI | ~30.3 GPM | ~97 GPM |
| Water Suction Rate at 40 PSI | ~227 GPH | ~631 GPH |
| Available Materials | Polypropylene (PP) or PVDF | Polypropylene (PP) or PVDF |
| Injector Type | Venturi / Differential Pressure | Venturi / Differential Pressure |
| Moving Parts | None | None |
| PP Warranty | 3 Years | 3 Years |
| PVDF Warranty | 6 Years | 6 Years |
| Brand | Mazzei | Mazzei |
* Performance values are at 40 PSI inlet / 0 PSI outlet. Actual suction rates vary with pressure differential. Consult the official Mazzei Performance Tables for full operating data across all pressures.
How do I size the correct Mazzei injector for my system?
Size by your system's total flow rate in GPH — add up the GPH of all emitters, drip tape, or sprayers in the zone — not by your mainline pipe diameter.
An oversized injector will produce no suction at all. When in doubt, choose a smaller size and install it on a bypass assembly to fine-tune performance.
Why is bypass installation preferred?
A bypass diverts only a portion of water through the injector, reducing pressure loss on the main line and allowing you to adjust the pressure differential — and therefore the suction rate — with ball valves.
This method also lets you stop injection without shutting down the main water supply to your system.
What fertilizers can I use with these injectors?
These injectors are designed for liquid concentrates or fully dissolved water-soluble fertilizers with less than 0.5% insoluble impurities.
Do not use undissolved granular or powdered fertilizer, as it can clog the injector or your downstream drip emitters. Always flush the irrigation system with clean water after each fertigation cycle.
Where can I get the bypass and suction assemblies for these larger units?
The bypass and suction assemblies for the 1-1/2" and 2" Mazzei injectors are not available online and must be special-ordered by calling DripWorks at 1-800-522-3747.
Note: the 1" suction assembly (IM1SA), available on our site, is compatible with the 1-1/2" Mazzei injector.
Build a fully functional Mazzei fertigation setup with these essential components:
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