DC Unit Sprinkler Valve Distance

[laspilitas.com]

Hi Guys,

For some unknown reason I thought I’d just try out the DC unit to replace one of my Hunter PRO-C’s and I ordered one but now I’m concerned I might have problems because the distance to the valves is around 600 ft in some cases. Does the unit convert the DC input to AC internally or does it really operate the AC valves with DC? Is that distance going to be a problem? If so, what is the max distance for running the DC unit at the recommended voltage?

I ordered another AC unit and I’m going to try to use it in the mean time, I have 2 other Hunter Pro-C’s to replace so I could use the DC unit for one of them but they both have pretty long runs too.

The irrigation valves are:
Irritol – 1″ (811 Solenoid) 24VAC, 60HZ, INRUSH AMPS 0.4, HOLDING AMPS 0.2 (read off solenoid itself)
Irritol – 3/4″ Same Solenoid as above.

Thanks,

– Ian

[ShawnHarte]

Your best bet is going to be to use a calculator such as http://www.calculator.net/voltage-drop-calculator.html

If you have a second pair of conductors you could pair them up to each valve on the DC unit. This will help with the DC drop, acting like power injection.

[Ray]

This depends on the wire resistance (and in turn affects the voltage drop as Shawn mentioned). Generally thicker wires work better as they have less resistance. If you know your wire’s gauge, you can use the calculator here to compute the resistance:
http://www.cirris.com/learning-center/calculators/133-wire-resistance-calculator-table
Assuming the valves need 0.2A holding current to operate, the resistance times 0.2A gives the voltage drop. Keep in mind that if the voltage drop is too steep, you can always switch the power adapter to something with higher voltage (like 12VDC adapter). OpenSprinkler DC is fairly flexible in terms of the input voltage and 12VDC adapters are pretty easy to find.

[Author]

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