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Rain Bird MJ100B 1 in Brass Flow Sensor for ESP-ME3

Rain Bird MJ100B 1 in Brass Flow Sensor for ESP-ME3

Brand: Rain Bird
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$209.29
$154.39
SKU MJ100B

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The Rain Bird MJ100B is a 1 in brass multi-jet flow sensor engineered for reliable residential and light-commercial irrigation monitoring. Designed specifically for use with ESP‑ME3 controllers, the MJ100B delivers precise flow measurement to help detect leaks, reduce water waste, and enable active flow management when paired with compatible Rain Bird controllers and the LNK WiFi module.

  • Accurate flow range: Measures 1.2 to 50 gpm (4.5–189.3 L/min) for consistent station-level monitoring.
  • Durable construction: Brass body with glass-filled nylon components resists pressure surges, physical damage, and corrosion.
  • ESP-ME3 integration: Wired connection and Flo-Watch™ compatibility allow automatic leak detection and selective zone shutdowns.
  • Learned Flow support: Works with controllers that learn station flow rates for improved accuracy without manual entry.
  • Analog register: Easy-to-read totalizing dial provides a local mechanical readout for flow verification.
  • Installation-friendly: Designed for straightforward plumbing connections; many retailers note included brass NPT unions for faster service and removal.

Important notes: do not use the MJ100B with unfiltered water sources that may contain debris (wells, ponds, or other unfiltered supplies). If the meter is full of water, protect it from freezing—drain through a downstream valve to winterize. Dimensions: 10.75" x 4.38" x 5.13" (273 x 111 x 130 mm). The MJ100B is ideal for contractors and homeowners seeking reliable, low-maintenance flow sensing that unlocks advanced controller features for smarter irrigation.

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Frequently Asked Questions

What flow range does the MJ100B measure?
The MJ100B measures approximately 1.2 to 50 gpm (4.5–189 L/min), suitable for station-level monitoring.
Is the MJ100B compatible with ESP-ME3 controllers?
Yes. It wires directly to ESP‑ME3 controllers and enables Flo‑Watch and learned-flow features for automatic leak detection.
How should I winterize the MJ100B flow sensor?
Drain the meter through a downstream valve before freezing weather; leaving water inside can cause permanent damage.