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R-200

 Gutter & Surface Mount Rain Sensor

INSTALLATION INSTRUCTIONS

MOUNTING

The R-200 sensor includes 2 mounting options:

1. 

Rain Gutter

2. 

Flat Surface

Mount the rain sensor where it will be exposed to direct, unobstructed rainfall 

(but away from sprinkler spray). 

The Switch-housing portion must be upright 

(See Figure 1)

.

Hints for mounting:
A. 

Mount as close as possible to the timer. This will cause the wire run to be shorter, which minimizes the 
possibility of wire breaks.

B. 

Mount in the highest possible position where rain can fall directly upon the rain sensor.

C. 

As described in the “Adjustments and Operation” section of the manual, 

“reset rate”

 refers to the amount of 

time it takes the rain sensor to dry out sufficiently for the sprinkler system to be allowed to come back on. 
The mounting location will affect this rate and should be taken into consideration should extreme conditions 
exist. For example, mounting the rain sensor on a very sunny, southeastern end of a building may cause 
the rain sensor to dry out sooner than desired. Similarly, mounting on the northern end of a building with 
constant shade may keep the rain sensor from drying soon enough. Some experimentation and use of the 

“vent ring”

 

(as described later) 

will usually yield satisfactory results.

Once the rain sensor is mounted, run the wire to the controller, using wire clips every few feet to fasten it. If an 
extension to the wire provided is needed, use the following table to determine the minimum wire gauge needed:

WIRING

IMPORTANT: 

The rain sensor is sold and designed for 24-VAC irrigation controllers only. All wiring must 

conform to applicable local codes. The two most common wiring situations are detailed below for controllers 
that do not have direct rain sensor & pump start relay wiring capabilities. For non-standard wiring situations, 
please consult your distributor.

A. 

24-VAC Solenoid Valves Only

 (No Pump Start Relay See Figure 2)

 With the two wires from the rain sensor  

at the controller, locate the “common ground” wire of the solenoid valves. If it is connected to the common 
terminal on the controller disconnect it. Attach one wire of the rain sensor to the

 “common”

 terminal 

(usually marked “COM”) 

on the controller. Attach the other wire of the rain sensor to the common wire 

leading to the valves. 

Note: The common wire to the valves does not have to be interrupted at the 

controller.The rain sensor may be wired anywhere along the common wire line.

B. 

24-VAC Solenoid Valves with Pump Start Relay 

(See Figure 3)

. Locate the common wire to the solenoid 

valves and the common wire lead to the coil of the relay that starts the pump. If these two wires are 
connected to the “common” terminal on the controller, disconnect both of them. Twist these two wires 
together along with one wire from the rain sensor and secure with a wire nut. Attach the other wire of the 
rain sensor to the “common” terminal on the controller.

CHECK TO VERIFY CORRECT WIRING

Turn on one zone of the sprinkler system that is visible while you are in reach of the rain sensor. Manually 
depress the spindle at the top of the rain sensor until you hear the switch “click” off. The sprinkler zone should 
stop instantly. If it does not, check wiring for correct installation.

ADJUSTMENTS AND OPERATION

The rain sensor can keep the irrigation system from 
starting or continuing after rainfall quantities of 1/8”, 
¼”, ½”, ¾”, or 1”. To adjust it to the desired quantity of 
rainfall, rotate the cap on the switch housing so that 
the pins are located in the proper slots 

(See Figure 4)

Do not forcibly twist the cap as this might break the pins. 
The time that it takes the rain sensor to reset for normal 
sprinkler operation after the rain has stopped is determined 
by weather conditions 

(wind, sunlight, humidity, etc.).

  

These conditions will determine how fast the hygroscopic 
discs will dry out, and since the landscape will also be 
experiencing the same conditions, the irrespective drying 
rates will roughly parallel each other. Note that there is 
an adjustment capability on the rain sensor that will slow 
down the reset rate. By turning the “ventring” 

(See Figure 

4)

 to completely or partially cover the ventilation holes, the hygroscopic discs will dry more slowly. This adjustment 

can compensate for an “overly sunny” installation location or peculiar soil conditions. Experimenting with the vent 
ring will best determine the ideal vent setting. 

Extension needed:

then use:

25-50 ft.
20 AWG

50-100 ft.
18 AWG

100 ft. or more
16 AWG

A

B

C

D

E

F

Cap

Vent Ring

Ventalation Holes

Housing

Mounting Bracket

24 VAC Wire to Controller

FIGURE 1: Mounting Rain Sensor

FIGURE 3: Wiring

FIGURE 2: Wiring

FIGURE 4: Parts Diagram

Timer - Controller

Line-In

Common Wire

to All Valves

Line-Out

(on Pump)

Pump

Start

Relay

Solenoid Valves

Rain Sensor

Timer - Controller

Common Wire

to All Valves

Solenoid Valves

Rain Sensor

Timer - Controller

Line-In

Common Wire

to All Valves

Line-Out

(on Pump)

Pump

Start

Relay

Solenoid Valves

Rain Sensor

Timer - Controller

Common Wire

to All Valves

Solenoid Valves

Rain Sensor

Timer - Controller

Line-In

Common Wire

to All Valves

Line-Out

(on Pump)

Pump

Start

Relay

Solenoid Valves

Rain Sensor

Timer - Controller

Common Wire

to All Valves

Solenoid Valves

Rain Sensor

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