Rain Collector (#7857 & 7857M)
This rain collector can be used with Vantage Pro2™
weather stations, including Vantage Pro2, Vantage
Pro2 Plus, and the Anemometer/Sensor Transmitter Kit.
The following instructions assume the rain collector
is being used with a Vantage Pro2 or Vantage Pro2
Plus Integrated Sensor Suite (ISS). Refer to the user
manual that came with your station for more information.
Manuals are available online at www.davisnet.com in the Weather Support section.
Note: Model number 7857 is factory-calibrated to take rain measurements in 0.01 inches. The
metric version of the rain collector, number 7857M, comes factory-calibrated to take
measurements in 0.2 mm.
Components
Please make sure you have all listed components before continuing.
• Rain collector cone latched onto base
• Base with tipping mechanism and 40’ (12 m) cable
• U-bolt, backing plate and 2 each: lag screws, flat washers, lock washers, and
hex nuts
• Debris Screen
•16 3.5” (9 cm) bird spikes (optional)
Debris Screen
(ts snugly
inside cone)
Bubble Level
BASE
14 Bird Spike
Sockets
RAIN
CONE
Finger Grips
TIPPING
MECHANISM
Latch
40’ Cable
U-Bolt
1/4" Flat
Washers
1/4" Lock
Washers
1/4" Hex
Nuts
Backing
Plate
HARDWARE KIT
1/4" x 3" Lag Screws
(~6 x 75 mm)
Bird Spikes (16)
3.5” (9 cm)
Prepare the Rain Collector
Tools and Materials Needed
You may need some of the following tools and materials to install the rain collector.
• Drill with 3/32” (2 mm) drill bit
• Medium Phillips screwdriver
• 3/16” (or 5 mm) wrench
• Cable clips or weather-resistant cable ties with screw holes or other means for
mounting
Rain Collector Internal Components
(Can be used to thread cable out and down)
Hole in Base
Tipping
Spoons
Magnet
Reed Switch
Bubble
Level
1
+ -
2
1
%
2
Restraining
Adjustment
Screw
Adjustment
Guide
Post
Drain
Screen
Cable Slot
Note: The rain collector is shipped with the 40’ cable coiled and exiting through one of the cable
slots. You may want to uncoil the cable and feed it down through the hole in the base
behind the tipping spoon.
Prepare the Rain Collector
1. Remove the cone from the base by rotating the base
until the latches on the cone line up with the latch
openings in the base, then lifting the cone away
from the base.
Twist off the rain collector cone
2
Installing the Rain Collector
2. Carefully cut and remove the plastic tie
Tipping Spoons
which holds the tipping spoons in place
during shipping.
Plastic Tie
Test the Rain Collector
Before installing the rain collector, test the unit. If you are replacing a rain collector
you previously installed, make a note of the total rainfall amount displayed. You
may want to reenter this amount after you test the rain collector.
1. Open the transmitter shelter on the ISS. Remove the foam insert and feed the rain
collector cable up through the opening. Plug the cable to the appropriate
connector in the sensor interface (See illustration on page 6.)
2. Press the RAIN
3. While watching the display on your console to see if it changes, slowly tip the
bucket until it drops to the opposite side. Each tip indicates 0.01" or 0.2 mm of
rain. (It may take up to a minute for the first tip to register at the console.) If the
display does not change, you may be tipping the bucket too quickly. Try again,
more slowly this time. If the rainfall amount displayed on the console increases
by the expected increment (either 0.01" or 0.2 mm) each time you tip the bucket,
your rain collector is working properly.
DAY button on your console to display rainfall.
Installing the Rain Collector
If you have not already done so, separate the cone from the base and disconnect the
rain collector cable from the sensor interface in the transmitter shelter.
Choosing a Location for the Rain Collector
Keep the following in mind when choosing a location for your rain collector:
• For accurate readings, you must mount the rain collector so that it is level. A
bubble level is built-in to the base to simplify this process.
• The rain collector contains a magnet-operated switch which may not operate
correctly if you mount the rain collector on or near any object which is attracted
to a magnet.
• Exposure to winds can reduce the measured rainfall amounts. Mount the rain
collector where there are no obstructions of rainfall at low angles -- such as trees,
houses, fences -- and as low as possible out of the wind.
• Choose a location which is easily accessible for normal cleaning and is distant
from trees or other sources of heavy pollen or debris.
3
Installing the Rain Collector on a Post or Flat Surface
Note: Climbing on your roof may be hazardous. If you are uneasy about installing your unit
please have a qualified professional complete the installation. Davis specifically disclaims
any liability for injury or loss resulting from the installation or use of the rain collector.
Installing the Rain Collector on a Post or Flat Surface
Refer to the following illustration to install the rain collector on a post or flat,
vertical surface.
Backing Plate
1/4" x 3"
Lag Screws
(For clairty, the tipping
mechanism is not shown.)
40' Cable
1. With a 3/16" (5 mm) drill bit, drill two holes approximately 21/8" (54 mm) apart.
Use the metal backing plate as a guide when marking the holes and a carpenter’s
level to ensure the holes are level.
2. Remove the rain collector cone if it is installed.
3. Insert the 1/4" x 3" lag screws through the metal backing plate and the holes in the
mounting base into the post. Make sure the base is level by checking the built-in
bubble level.
4. Tighten the lag screws using an adjustable wrench or 7/16" wrench.
4
Installing the Rain Collector on a Pole
Installing the Rain Collector on a Pole
Accessories for Pole Mounting
• Use the Mounting Tripod (#7716) for easy roof-mounting.
• Use the Mounting Pole Kit (#7717) to raise the installation height of the rain
collector by up to 37.5" (0.95 m).
General Guidelines for Installing on a Pole
• With the supplied U-bolt, the rain collector can be mounted on a pole having an
outside diameter ranging from 1
• A larger U-bolt (not supplied) can be used to mount to a pole with a maximum
outside diameter of 2
1
/2" (64mm).
• To mount on a smaller pole, obtain a U-bolt that fits the base openings but that has
a shorter threaded section. If the included U-bolt is used with a smaller pole, the
bolt will interfere with the rain collector cone.
• Use the built-in bubble level to ensure rain collector is level.
Refer to the following illustration when installing the rain collector on a pole.
1
/4" to 13/4" (32 – 44mm).
1/4" Hex Nut
1/4" Lock Washer
Backing Plate
Groove for
U-Bolt
Rain Collector
U-Bolt
Base
1. While holding the mounting base against the pole, place the two ends of a U-bolt
around the pole and through the two holes in the base.
2. Slide the metal backing plate over the bolt ends as they stick out toward the rain
collector cone. Secure the backing plate with a washer, a lock washer, and a hex
nut on each of the bolt ends. Adjust the height of the rain collector, then tighten
the nuts.
5
Finishing Steps
Finishing Steps
1. Open the transmitter shelter on the ISS.
Remove the foam insert and feed the rain
collector cable up through the opening. Plug
the cable to the appropriate receptacle in the
transmitter. Replace the foam and close the
shelter.
2. To be certain the rain collector is functioning properly after installation, retest the
unit. See “Test the Rain Collector” on page 3.
3. To use bird spikes, insert one spike into each socket
around the rim of the cone. The sockets are tapered:
push firmly or tap lightly with a hammer for a more
secure fit.
4. Place the cone back onto the base by putting the
latches on the cone into the latch openings in the base
and rotating the cone clockwise until the latches
“lock” into place. As you reattach the cone, make sure
to run the cable to the cable slot in the base, or the
cone will not fit snugly against the base. (You may
also run the cable down through the hole in the base.)
5. Place the debris screen, pointed end up, into the cone.
The screen prevents large bits of debris from blocking
the funnel hole. If bird nesting is a problem, you can
place a spike in the hole on top of the debris screen.
Note that using a bird spike in the debris screen may
make the screen more likely to be blown over or out in
a high wind gust.
Be careful; bird spikes may be sharp.
Note: If you choose not to install the bird spikes, we recommend that you keep the packet of
spikes in case birds become a problem in the future.
Transmitter
Shelter
Sensor
Interface
Foam
Insert
6. To prevent fraying or cutting of the cable where it is exposed to weather, it is
important that you secure it so it doesn’t whip about in the wind.
Use cable clips or weather resistant cable ties to secure the cable. Place clips or ties
approximately every 3 to 5 feet (1 to 1.6 m). Do not use metal staples or a staple gun
to secure cables. Metal staples, especially when installed with a staple gun, have a
tendency to cut the cables.
6
Adjusting the Rain Collector
Extending Cable Runs
If the cable length supplied with the rain collector is not long enough for your
purposes, you may extend it. The maximum length of cable is 900 feet (274 m). To
extend the cable, purchase standard 4-Conductor Extension Cables from Davis and
connect them to the existing rain collector cable.
Adjusting the Rain Collector
The non-metric version of the rain collector is calibrated at
the factory so the spoons tip (and records rainfall) for each
0.01" of rain. The metric version is calibrated so the
spoons tip for each 0.2 mm. To adjust the calibration
slightly, use a 3/16” (or 5 mm) wrench to rotate the
adjustment screws which are located underneath the
tipping spoons. (See “Rain Collector Internal
Components” on page 2.) The adjustment guide embossed
in the platform shows how far you must rotate both screws in turn to effect a 1% and
a 2% change. Moving the screws in the positive (+) direction causes the spoons to tip
more times (i.e. give a larger count) for a given amount of water.
Note: Modify both adjustment screws by the same amount.
To check the accuracy of the rain collector, compare the Davis rain collector with a
tube type rain gauge. Use a rain gauge with an aperture of at least 4 inches. Any
smaller and the readings obtained may not be accurate. Place the tube type rain
gauge directly next to the Davis rain collector. Compare the totals on three storms to
determine whether your rain collector needs calibration and by how much. Adjust
the screws to fine-tune the reading for the next three storms if necessary.
Note: Avoid comparison to rainfall readings obtained from television, radio, newspapers, or
neighbors’ readings. Such readings are not an accurate measurement of the weather
conditions in your specific location. The rain collector is carefully tested at the factory to
conform to the specifications listed in the back of this manual.
Maintaining the Rain Collector
For greatest accuracy, you should thoroughly clean the rain collector at least once or
twice a year.
1. Disconnect the rain collector cable from the sensor interface in the transmitter
shelter.
2. Separate the cone from the base.
3. Use a soft damp cloth to clean pollen, dirt, and other debris from the cone, cone
screens, and bucket.
4. Use a pipe cleaner to clear the funnel hole in the cone and the drain screens in the
base. When all parts are clean, rinse with clear water.
5. Reattach the cone and replace the debris screen. Reconnect the rain collector
cable to the sensor interface.
7
Troubleshooting Guide
Rainfall is not registering on the console or the console has a large error.
• Check the cable connections from the sensor to the console. Cable connections
account for a large portion of the potential problems. Connections should be firmly
seated in the jacks and plugged in straight. If a reading appears intermittently on the
display as you jiggle the cable, the connection is faulty.
• Make sure there is no magnetic, steel, or iron object near the rain collector.
• Make sure the funnel hole in the cone is clear so water can empty into the spoons.
• Make sure the spoons move freely when tipping to both sides. The console should
show an increase in rainfall for each tip of the spoons. (If the spoons do not move at
all, check that you have cut the cable tie that holds them in place during shipping.)
• Make sure the rain collector is mounted so that it is level.
Contacting Davis Technical Support
If you have any questions about your rain collector, please contact Davis Technical
Support. We’ll be glad to help.
(510) 732-7814 — Monday - Friday, 7:00 a.m. - 5:30 p.m. Pacific Time.
(510) 670-0589 — Technical Support FAX.
support@davisnet.com — E-mail to Technical Support.
info@davisnet.com — General e-mail.
www.davisnet.com — Davis Instruments website.
Specifications
Sensor Type . . . . . . . . . . . . . . . . . . . . Tipping bucket with magnetic reed switch
Output . . . . . . . . . . . . . . . . . . . . . . . . . Contact closure
Attached Cable . . . . . . . . . . . . . . . . . . 40’ (12 m), 4-conductor, 26 AWG
Connector . . . . . . . . . . . . . . . . . . . . . . Modular connector (RJ-11)
Recommended Max.Cable Length . . . 900’ (270 m)
Housing Material . . . . . . . . . . . . . . . . . UV-stabilized ABS plastic
Dimensions with base, no spikes . . . . 9.25” wide x 10.25” high x 11” deep (23.5 x 26 x 28 cm)
Collection Area . . . . . . . . . . . . . . . . . . . 33.2 in2 (214 cm2)
Range
Daily Rainfall . . . . . . . . . . . . . . . . . 0.00” to 99.99” (0.0 mm to 999.8 mm)
Total Rainfall . . . . . . . . . . . . . . . . . 0.00” to 199.99” (0.0 mm to 6553 mm)
Accuracy . . . . . . . . . . . . . . . . . . . . . . . .For rain rates up to 2"/hr (50 mm/hr): ±4% of total or +0.01”
Update Interval . . . . . . . . . . . . . . . . . . . .20 - 24 seconds
Input/Output Connections
Red . . . . . . . . . . . . . . . . . . . . . . . . . Switch terminal
Green & Yellow . . . . . . . . . . . . . . . .Switch terminal
Product Number: 7857 Rain Collector Part Number: 07395.335 Rev B (6/13/14)
This product complies with the essential protection requirements of the EC EMC Directive 2004/108/EC.
Copyright © 2014 Davis Instruments Corp. All rights reserved. Davis Instruments Quality Management
System is ISO 9001 certified. Information in this document is subject to change without notice.
(0.2mm) (0.01" = one tip of the bucket) whichever is greater. For
rain rates from 2"/hr (50 mm/hr) to 4"/hr (100 mm/hr): ±5% of total
or +0.01” (0.2mm), whichever is greater.
®
3465 Diablo Avenue, Hayward, CA 94545-2778 U.S.A.
510-732-9229 • Fax: 510-732-9188
E-mail: info@davisnet.com • www.davisnet.com
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