The HRC-100-RS-HW is a hard-wire rain sensor designed to integrate with 24-Volt irrigation controllers, providing water conservation, convenience, and flexibility to automatic watering systems. Its primary function is to prevent sprinklers from running during or immediately after rainfall, ensuring that irrigation only occurs when necessary.
Function Description:
The sensor operates by detecting rainfall. Once a predetermined amount of rain has fallen, the sensor engages a switch that interrupts the irrigation controller's circuit, preventing the timer from activating the sprinklers. This ensures that the watering system is automatically paused during wet conditions. The sensor also incorporates a temperature-sensitive element; once the rain sensor has dried sufficiently or the ambient temperature rises above 37°F (3°C), the sensor disengages, allowing normal sprinkler operation to resume. This dual mechanism (rain detection and drying/temperature reset) optimizes water usage by preventing unnecessary irrigation.
Important Technical Specifications:
- Compatibility: Designed exclusively for 24-Volt irrigation controllers. All wiring must comply with applicable local electrical codes.
- Rainfall Settings: Adjustable to prevent irrigation after rainfall quantities of 1/8", 1/4", 1/2", 3/4", or 1". This adjustment is made by rotating the cap on the switch housing to align pins with the desired slots.
- Reset Mechanism: The sensor resets (allows normal operation) when the hygroscopic discs dry out or when the temperature rises above 37°F (3°C). The drying rate is influenced by weather conditions such as wind, sunlight, and humidity.
- Wiring: The sensor includes two wires for connection to the controller. For 24-Volt solenoid valves without a booster pump, one sensor wire connects to the "common" terminal (usually marked "COM") on the controller, and the other connects to the common wire leading to the valves. For 24-Volt solenoid valves with a booster pump, the common wire to the solenoid valves and the common wire lead to the pump relay coil are twisted together with one sensor wire, secured with a wire nut, and the other sensor wire connects to the "common" terminal on the controller. The pump circuit output must be 24 volts in this configuration.
- Wire Gauge Requirements for Extensions:
- 25-50 ft. extension: 20 AWG
- 50-100 ft. extension: 18 AWG
- 100 ft. or more extension: 16 AWG
- Microswitch: UL-approved for electrical safety.
Usage Features:
- Mounting Options: The sensor comes with two mounting options: a 1½" threaded adapter and a rain gutter or flat surface adapter. It should be mounted in a location exposed to direct, unobstructed rainfall, away from sprinkler spray, with the switch-housing portion upright.
- Adjustable Rainfall Sensitivity: Users can select the desired amount of rainfall (1/8", 1/4", 1/2", 3/4", or 1") that will trigger the sensor to shut off the irrigation system. This is done by rotating the cap on the switch housing.
- Adjustable Reset Rate (Vent Ring): The sensor features a "vent ring" that can be adjusted to completely or partially cover the ventilation holes. This controls the drying rate of the hygroscopic discs, allowing users to slow down the reset rate. This feature is useful for compensating for specific installation locations (e.g., very sunny or constantly shaded areas) or unique soil conditions, ensuring the sensor dries out at a rate that aligns with the landscape's actual drying needs.
- Bypass Capability: If temporary bypass of the sensor's operation is needed (e.g., to run the system despite recent rainfall), users can simply raise the rain quantity "cap" setting to a higher value or remove it altogether. This releases pressure from the switch button, allowing the valve circuit to close. Note that using the "manual" switch on the controller will not bypass the sensor.
- Troubleshooting Guide: The manual provides a comprehensive troubleshooting section for common issues such as the system not coming on at all (checking sensor discs, wire breaks, switch functionality) and the system not shutting off after heavy rainfall (checking wiring, sensitivity settings, and obstructions).
Maintenance Features:
- No Required Maintenance: The HRC-100-RS-HW is designed to be maintenance-free.
- No Winterization Removal: The sensor does not need to be removed or covered for winterizing purposes.
- Replaceable Parts: All components are easily replaceable if they become damaged or lost. The spindle assembly is designed to remain with the cap and should not be pulled apart.
- Durability: Hydro-Rain® warrants the product to be free from defects in materials and workmanship for a period of three years from the date of purchase, indicating a robust design.
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