DAVIS Fan-Aspirated Radiation Shield User Manual
AN
F
ADIATION
R
NSTALLATION
I
(For all models with Mfg. Code
beginning with B or higher)
The Fan-Aspirated Radiation Shield uses fan aspiration and passive shielding
to minimize the effects of solar radiation and to provide accurate temperature
readings. This instruction manual takes you step-by-step through the process
of installing and mounting your Fan-Aspirated Radiation Shield.
Note: Installation varies according to the shield type, so please take note of your product number before
you begin to install. You can find the model number on the label on the underside of the Fan Plate.
SPIRATED
-A
S
ANUAL
M
HIELD
Components
The Fan-Aspirated Radiation Shield includes these items:
Mounting Bracket
with Solar Panel
SOLAR MODELS
7755, 7756, 7757
ONLY
Mounting Bracket
AC MODELS
7750, 7751, 7752
ONLY
Standard
Sensor Cable,
40 feet (12 meters)
MODELS 7751, 7756
ONLY
#4 x 1/2" Screw
#4 Flat Washer
Cable Clamp
Fan-Aspirated
Radiation Shield
Industrial
Sensor Cable,
16 feet (4.9 meters)
MODELS 7752, 7757
ONLY
Junction Board Cover
3 Volt
Power Adapter
AC MODELS
7750, 7751, 7752
ONLY
SOLAR MODELS 7755, 7756, 7757 ONLY
#4 Self-Threading Screws (4)
Battery Covers (2)
1.2 Volt Nicad Batteries (2)
O-Rings (2)
Product # 7750, 7751, 7752, 7755, 7756 & 7757
#8 Hex Nuts (3)
#8 Lock Washers (3)
#8 Flat Washers (3)
A Note About Model Versions
This manual is for all versions of the Fan-Aspirated Radiation Shield manufactured after 9/1/01. Earlier versions have the following differences:
Solar-powered modules only use one battery versus two batteries
✦
All Junction Board-connections are soldered versus using connectors
✦
Aside from those differences, the installation of the early versions of the
Fan-Aspirated Radiation Shield is the same as for current versions.
Tools and Materials Needed
To disassemble, install, and mount your Fan-Aspirated Radiation Shield, you
may need the following:
✦
A medium Phillips-Head screwdriver.
A small Phillips-Head screwdriver.
✦
To install an existing Davis Temperature/Humidity sensor.
✦
A small wrench or 3/8” (9 mm) nutdriver.
A radiation shield bracket (#7994).
✦
To mount the radiation shield on a mast or pipe if you wish.
Installation Steps
The Fan-Aspirated Radiation Shield comes pre-assembled. Depending on your
model number, you may need to disassemble your shield to install a battery
and/or a sensor or probe. Here are the installation steps for each shield.
ODEL
M
7750
1. Disassemble the shield
Page 3
2. Install a sensor or probe
Page 4
3. Install the sensor board
Page 6
4. Power the fan
Page 8
5. Route the cables
Page 10
6. Reassemble the shield
Page 12
7. Mount the shield
Page 15
Page 2 Fan-Aspirated Radiation Shield
M
ODELS
7751
& 7752 M
1. Disassemble the shield
Page 3
2. Power the fan
Page 8
3. Reassemble the shield
Page 12
4. Mount the shield
Page 15
ODEL
7755
1. Disassemble the shield
Page 3
2. Install a sensor or probe
Page 4
3. Install the sensor board
Page 6
4. Power the fan
Page 8
5. Route the cables
Page 10
6. Reassemble the shield
Page 12
7. Mount the shield
Page 15
M
ODELS
7756
& 7757
1. Disassemble the shield
Page 3
2. Power the fan
Page 8
3. Reassemble the shield
Page 12
4. Mount the shield
Page 13
N
Disassembling the Radiation Shield
Use a medium Phillips-Head screwdriver to disassemble as described below:
1. Unscrew the three screws at the top of the unit and remove the mounting
bracket.
2. Remove the two plates and put aside.
3. Gently remove the fan and the deflector, taking care not to stress the wires
soldered to the terminal board.
4. Slide out the sensor board.
5. You are now ready to install a sensor or probe. (See page 5.)
2" Screws (3)
Lock Washers
Flat Washers
Mounting Bracket
with Solar Panel
SOLAR MODELS
Closed Plate
(no hole in center)
Open Plate
(hole in center)
Fan Unit
Fan Deflector
Sensor Board
with Temp Probe
emp/Humidity Sensor
ACTORY INSTALLED
MODELS 7751, 7752,
7756, AND 7757;
DO NOT REMOVE)
Power Cable
AC MODELS
Core Unit
Disassembling the Shield
Motor
Connector
Fan Plate
Battery Compartment
Baffles
Air Inlet (underneath)
Mounting
Bracket
AC MODELS
Solar Power Cable
SOLAR MODELS
Disassembling the Radiation Shield Page 3
Installing a Sensor or Probe
For models without a pre-installed sensor, continue to the section “To install a
sensor or probe on the sensor board.” (See below).
If you want to install your own Davis T emperatur e/Humidity sensor (#7859 or
#7860), you must remove your old sensor housing and attach a new and
smaller sensor board cover. Please continue to the section “To attach a new
sensor board cover.” (See below.)
To install a sensor or probe on the sensor board:
1. Attach the sensor or probe to the board using the cable ties.
Sensor
Board
Davis
Temp Probe
Cable Ties
(2 places)
Installing a Sensor or Probe on the Sensor Board
Sensor
Board
Vaisala
Temp Probe
Cable Ties
(2 places)
2. You are now ready to install the sensor board. (See page 6.)
To attach a new sensor board cover:
If you have an existing Temperature/Humidity sensor model # 7859 or # 7860,
you need to attach a new sensor cover as follows:
1. Remove the shell and main cover by removing the screw at the front of the
board beside the cable exit point.
2. Remove the warranty label on the back of the cover and undo the screw.
Note: Removing this warranty label to attach a new sensor board does not void your warranty in this
instance. To avoid damaging sensitive components on the PC board, hold the board by the edges.
Page 4 Fan-Aspirated Radiation Shield
3. Remove the sensor board and discard the “old” cover and shell.
#4 x 3/8"
Screw
Shell
Main
Cover
Sensor
Board
#4 x 3/8"
Base
Screw
#4 x 3/8"
Removing the “Old” Temp/Hum Housing
4. Fit the new sensor cover on the front of the sensor board as shown below.
Board removed from
Davis #7859 or #7860
Temp/Humidity
Sensor
Sensor
Cover
Screw
#4 x 3/8"
Screw
Attaching a New Sensor Board Cover
5. Insert and tighten the #4 x 3/8” (9.5 mm) screw in the back of the sensor
board.
6. You are now ready to install the sensor board.
Installing a Sensor or Probe Page 5
Installing the Sensor Board
Here’s how to install the sensor board supplied with the radiation shield:
1. Insert the board into the grooves in the sensor chamber walls.
2. Push the cable gently into the sensor chamber, allowing the cable to loop a
little.
3. Route the cable to the cable channel.
Sensor
Chamber
Cable
Channel
Temp/Humidity
Sensor Board
with
Sensor Cover
Installing the Sensor Board
OR
Core Unit
Temp Probe
mounted on
Sensor Board
Page 6 Fan-Aspirated Radiation Shield
Installing the Fan
Here’s how to install the fan:
1. Install the fan deflector, ensuring that the sensor cable is in the cable channel molded into the fan deflector and the fan plate.
Fan Unit
Motor Connector
Fan Deflector
Fan Plate
Junction Board
Installing the Fan
2. Place the fan unit on top of the deflector.
3. Connect the motor power cable to the Motor Connector on the Junction
Board.
Installing the Fan Page 7
Powering the Fan
AC-powered models are powered by an AC-power adapter. Solar-powered
models have a solar power panel and use batteries for overnight power. Refer
to the Junction Board Connections illustration when powering the fan.
Solar Power Connector
(Solar-Powered Models Only) Motor Connector
MOTOR
+VSOL
For Future
Tachometer
+5V
AC Power Adapter Connector
(AC-Powered Models Only)
Junction Board Connections
TACH
AC-Powered Radiation Shield
1. Locate the Junction Board on the fan plate (See page 7).
2. Connect the AC-power adapter to the +5V connector on the Junction Boar d.
3. Plug the AC-power adapter into an AC outlet.
4. Check to see that the fan is blowing air up and away from the sensor.
5. Unplug the AC power adapter from the AC outlet until you have finished
mounting the radiation shield.
6. Secure the AC power cable to the fan plate with the supplied cable clamp.
7. You are now ready to route the cables.
Junction
Board
AC Power-Adapter Connections
Page 8 Fan-Aspirated Radiation Shield
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