Melnor Industries AquaSentry Automatic Rain Delay for Melnor water Timers 3300 Leaflet

soil is too dry, select the wetter setting (three droplets). Continue to 

monitor your particular watering requirements based on weather 

conditions and overall plant health.
Attach the Receiver to the Timer

Newer timers will require you to attach the included adapter rail 

onto the timer first. Slide the rounded end of the adapter rail into 

the matching slot on the top of the timer. Slide the receiver onto 

the rail along the top of your timer. The receiver does not need 

to slide fully on to work properly. You may need to leave a gap to 

allow for operation of the faucet.
Connect the Receiver cable to the socket located on the bottom of 

your timer. Note the orientation of the three (3) pins to be certain 

the cable is attached correctly.
For a diagram showing the connection to your specific timer, go to 

the instructions tab at www.melnor.com  
Checking the Connection

After installing the receiver, press any button once to wake the 

timer. If the AquaSentry® system is working properly, an antenna 

symbol (along with the word “AUTO” on some models) should 

appear as shown within 35 seconds indicating communication 

between the AquaSentry® and AquaTimer™. If the symbol displays 

steadily, your AquaSentry® is working properly and monitoring the 

soil’s moisture level.

If the antenna symbol is flashing, one of the following has occurred:
a. The batteries in the moisture sensor are not installed properly or 

they are too weak.

b. The Moisture Sensor is out of range.
c.  Sensor still set to “Off”.
If the antenna symbol fails to appear, the connection between the 

Receiver and the AquaTimer™ is faulty.
Check all of the above. Wait for 5 minutes or until the AquaTimer™ 

display turns off. Then wake the AquaTimer™ and watch for the 

antenna symbol. The antenna symbol should appear within 35 

seconds. Over time, if the antenna symbol begins to flash, the 

batteries in the Sensor are weak and need to be replaced.

 

Melnor is a registered trademark of Melnor, Inc.

3300_INS_EN_WEB_02

This unit requires a Melnor® electronic water 

timer model 3015, 3060, 3100 or 3280 (not 

included) that includes a connector for this Automatic 

Rain Delay. Follow the timer instructions to program 

the timer. For more information, call 877-283-0697.
Install the Batteries

Remove the two small screws and remove the battery 

cover. Insert two, fresh AA batteries. Please note the 

positive (+) and negative (–) ends of the batteries and 

ensure they are inserted correctly following the markings 

inside the battery compartment.
Replace the battery cover and screws. A fresh set of quality 

batteries should last a full watering season or about nine months.
Place the Moisture Sensor

CAUTION: Never use a hammer or any other 

tool to pound the unit into the ground. Do not 

attempt to force the unit into the ground. This will 

damage the Sensor. The AquaSentry® has a maximum 

wireless range of 200 feet (60 meters). The Sensor must 

be placed within the area you are watering. For best 

operation, place the Sensor in direct sight of the Timer/Receiver. 

The Sensor can be placed out of direct sight of the Timer/Receiver, 

but the range may be diminished somewhat.
To insert the Sensor, first dig a pilot hole about the same size as the 

probe. The hole must be deep enough to bury the entire sensor 

probe. Remove any large rocks or other debris from the extracted 

soil. Place the Sensor into the hole so that the entire probe is under 

ground level. The face of the Sensor unit should be turned toward 

the Timer/Receiver. Return the soil to the hole and pack firmly into 

place. It is important that the entire front surface of the probe be in 

contact with the soil.
Selecting the Desired Moisture Level

Individual grass and plant species have varying moisture 

requirements. The AquaSentry® Moisture Sensor has three 

moisture settings plus OFF. Melnor® recommends initially setting 

the knob to the medium setting (two droplets). After a week, you 

should reassess the moisture in the area you are watering. If the soil 

is too wet, adjust the unit to the dryer setting (one droplet). If the 

for Melnor Water Timers

User Instructions

Sensor

Adapter

Receiver