Upgrade of Existing System,
Using Existing Wiring
Communication Cable Type
Should be 2 or 3 copper conductors, solid or stranded,
with PE pr PVC insulation, rated for at least 600V. For
3-conductor cables, the third conductor will not be used
and any exposed ends must be capped and sealed with an
approved splice.
Communication Cable Length
The maximum wire run from the SmartHub to the farthest
decoder is 6800’ (2072 meters) for 14 AWG (2.5mm
2
) cable.
The total amount of wire path is 14,000’ (4267 meters) for
14 AWG (2.5mm
2
) cable.
Resistance
The maximum resistance of the wire path with the end
shorted can be 37.7 Ohms. The minimum resistance of the
wire path with the end open should be 1000 Ohms.
Noise
For the wire path to be tested, disconnect from the DIU (or
other controller), connect an oscilloscope across the wire
path, and power up the pump and any other equipment
that would be running when watering. Measure the voltage
across the open wire path. It should be less than 1 V p-p.
Short Circuits
After the GAC decoders are installed, measure the
resistance across the two open wire path wires to insure
that it is still greater than 1000 Ohms to insure that no
shorts were introduced during the installation process.
Communication Cable to Power Cable Spacing
This recommendation applies to GAC communication
installation. This minimum spacing to any power cable
should be maintained to minimize the possibility of
electrical interference which could affect the integrity of
the GAC communication to decoders. If there are power
cables already installed running next to the communication
cables that do not meet the minimum spacing, remdiation
will be required to meet the minimum spacing listed in
Table 2
below.
Table 2
Power Cable Circuit
Rating
(Minimum KVA*)
Recommended Minimum
Spacing**
0-3
6 inches (15 cm)
3-10
12 inches (30 cm)
10-20
24 inches (60 cm)
20-50
36 inches (90 cm)
50-100
48 inches (120 cm)
>100
60 inches (150 cm)
*Maximum voltage x current rating of circuit
**These are minimum spacing recommendations
to minimize noise coupling. There may be greater
separation required by safety agencies or local codes.
Decoder to Sprinkler Wires
Wire Type - Should be copper conductors, solid core, with
PE or PVC insulation, rated for at least 600V
Wire Length
For 16 AWG or 1.5mm2 – Maximum length is 575 feet
(175m)
For 18 AWG or 0.9mm2 – Maximum length is 400 feet
(122m)
Decoder Module Installation
Remove an old decoder by cutting out the old splices. Make
sure to cut the communication wires and station wires back
to remove any green or corroded copper. Strip the wires
and connect a new decoder module per Figure 4. All splices
must be made with approved splice kits.
Valve Compatibility
Toro
Golf VIH (Solenoid 89-1905 or 118-0248)
at 150 PSI
400ft (122m) Max Solid Core, 18 AWG
or 0.9mm2 Cable 2.3 Ohms/Conductor
(400ft), 1 per Output
575ft (175m) Max Solid Core, 16 AWG
or 1.5mm2 Cable 2.3 Ohms/Conductor
(575ft), 2 per Output
Toro
252 Valve (Solenoid 102-1905 or 118-0248)
at 150 PSI at AC Decoder, 1 per Output
Toro
220 Valve (Solenoid 102-0927) up to 220
PSI (passing is 150 PSI) at AC Decoder,1
per Output
Toro
216 Brass Valve (Solenoid 89-1673), Up
to 220 PSI (passing is 150 PSI) at AC
Decoder, 1 per Output
Rain Bird
Green Golf VIH Solenoid at 150 PSI
200ft Max Solid Core, 18 AWG or 0.9mm2
Cable 1.2 Ohms/Conductor, 1 per Output
328ft Max Solid Core, 16 AWG or 1.5mm2
Cable 1.2 Ohms/Conductor, 2 per Output
Rain Bird
DV Solenoid (Black Wires) at 150 PSI at
AC Decoder, 1 per Output
Rain Bird
PGA/PESB Solenoid (White Wires) at 150
PSI at Decoder, 1 per Output
14
Lynx® SmartHub Installation and User Guide
