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PurpHaze
10-06-2007, 11:20 AM
LondonRain brought up some interesting insights that I'd like to explore further before committing my new design to a 2-wire system.

Still not a big fan of 2 wire systems. If installing a 2 wire system you better provide a as-built with valve locations/zones because a 521 will not locate a valve on a 2 wire the same way as a multi wire systems.

I'm assuming that this is because the wire path between the decoders in the field and the valves themselves is not "open" unless the decoder is communicating with them? Can you trace between the controller and the decoders like in a multi-wire system?

Almost all of my trouble shooting equipment is useless on a 2wire system.

Do the decoders act kinda like an "isolation valve" in that signals only go between the decoder and the valves when the controller activates the decoder?

You will also need a detailed path of wire runs.

That's a given on anything I install, anything major we repair or problematic systems where I will document main line and valve locations for future reference. Just yesterday I was able to reference a scaled "valve location as-built" I'd made up on a newer system (30+ field valves) where we didn't have an original contractor as-built. We had spent many hours locating the valves and putting them down on a plan since I just knew the site guy would not keep the boxes uncovered and I just knew that we'd have future problems since the original system was installed by one of our least favorite contractors. I was able to direct Leo via Nextel walkie-talkie to the general area where the suspect hung valve was located and he was able to locate it and reair the problems. He said I was within about 3' of where I'd indicated.

This 2 wire system we maintain is always having problems with the field receivers, either the zone or multi zones will be running or not running at all.

What type of system decoders/controller does this one have? Are they installed in their own boxes or as part of the valve/box installation? Are they single, multiple valve decoders or a combination?

2 wire is a pain to trouble shoot, you must go to every single valve and find out what it is doing, is the receiver working or not, is the wiring good to each valve, is the solenoid good, every connection must have a proper connection.

By its very nature the decoders give you another level of "controller" interface and potential problems which could become a real PITA.

In the long run "this" 2 wire system has cost the homeowner more than if a multi wire system had been installed.

Was this system installed by another contractor or did you do the install yourself?

hoskm01
10-06-2007, 11:33 AM
New field Purp?

Do I understand correctly that the only real advantage in 2 wire is programability and reduction in copper?

londonrain
10-06-2007, 11:57 AM
Since you only have 2 wires and it must be a continuous wire with no tee-offs in the wire you trace the entire wire path all over the area for every valve not just one valve . Most of the time doubling back the same path since it is continuous wire run or it could be a dead wire at a valve and you are tracing back the same wire again. The field receiver/decoder must be activated for the current to pass through and activate the solenoid, if dead receiver then no solenoid signal, no solenoid activation/coiling and the 521 passes right past. Yes the decoder acts like a isolation valve, no signal no activation of the solenoid. This is a Hit 2 wire system and they are installed in their own boxes with decoder...and another contractor installed the system.
Yes it is a pain trouble shooting. What I end up doing is using my station master and a solenoid then testing the 2 wires between two valve locations, if good move on to the next area. The last time I was out trouble shooing we had a dead wire and since I do not know the exact path of the wires it was a real pain... one of the decoders went bad so it showed a short on the station master when hooded up on the 2 wires, so I had to disconnect decoders until if figured out what was happening...once again just a real pain...

PurpHaze
10-06-2007, 12:16 PM
New field Purp?

Just curious about new technologies available to us. :)

Do I understand correctly that the only real advantage in 2 wire is programability and reduction in copper?

What I'm keenly interested in is the ability to add on to an existing system with just the two wires present. We're constantly in a state of flux as things (such as buildings, play boxes, asphalt play areas, etc.) are brought in and then removed or modified.

PurpHaze
10-06-2007, 12:21 PM
Since you only have 2 wires and it must be a continuous wire with no tee-offs in the wire you trace the entire wire path all over the area for every valve not just one valve.

It's my understanding that you can tee into the 2-wire path to add on. Does it have to be a "broken tee" (where you'd tee in, go to your new set of valves and then return to the tee-in point to continue the wire path to your existing decoders/valves further down the line) or an "unbroken tee" where you just tie in for your new spur and the old spur stays intact?

Guess I'll have to do some more reading to better understand the wiring routing. :)

londonrain
10-06-2007, 12:33 PM
Yes you can tee in. Cut old wires, connect new wires to one end of cut wires and run new wires, double back new wires and connect to the other end of the old cut wires.

londonrain
10-06-2007, 12:38 PM
You only want one dead end wire path.......

londonrain
10-06-2007, 12:49 PM
Wiring is one of the most important parts of a 2 wire system..Here is a pic of the connectors Hit supplies with each decoder.

BrandonV
10-06-2007, 03:19 PM
now with the hunter acc you can run up to 6 paths and they you can dead end all you want, at least from what I understand. nothing had to be looped, and you could tee in anywhere you want. i also used the pre braided wire.

londonrain
10-06-2007, 05:00 PM
now with the hunter acc you can run up to 6 paths and they you can dead end all you want, at least from what I understand. nothing had to be looped, and you could tee in anywhere you want. i also used the pre braided wire.Correct if your controller can run 6 paths you will have 6 dead ends, 1 for each path. The Hit logic 1 has one path only thus 1 dead end path. You will not want 1 path with more than one dead end. With the Hunter 2 wire you connect the decoder on the 2 wire path, then you can run up to 150f of extra wire from decoder to the solenoid. You will not want to tee into the 2 wire and run more of the 2 wire to the solenoid and dead end it.

Kiril
10-07-2007, 01:18 PM
For trouble shooting 2 wire systems, perhaps something similar to this may be the solution. This allows you to trace faults using a single wire.

http://www.riserbond.com/products.asp?sec_id=2697

londonrain
10-07-2007, 02:16 PM
For trouble shooting 2 wire systems, perhaps something similar to this may be the solution. This allows you to trace faults using a single wire.

http://www.riserbond.com/products.asp?sec_id=2697
You still can use the 521 and ground fault for tracing the wires and faults....

Rotor_Tool
10-07-2007, 02:41 PM
It's my understanding that you can tee into the 2-wire path to add on. Does it have to be a "broken tee" (where you'd tee in, go to your new set of valves and then return to the tee-in point to continue the wire path to your existing decoders/valves further down the line) or an "unbroken tee" where you just tie in for your new spur and the old spur stays intact?

Guess I'll have to do some more reading to better understand the wiring routing. :)

Purp, with the Rain Bird system you can dead-end on multiple tee's. The controller has 3 outputs allowing three separate wire runs. The design manuals given to me by my rep indicate you can tee off of the main two wire path as many times as you wish, but these tee's should be considered part of the "critical path" if the two-wire path is not looped so you don't run the wire too far and over-extend the voltage capabilities of the system.

I see Londonrain has had issues with the Hit system, the old adage really rings true with two-wire technology...you get what you pay for. The Rain Bird controller and components are not cheap, but they work great. The programming interface is a little cumbersome at first, but once you have been through it a couple of times - it's not bad.

Kiril
10-07-2007, 11:09 PM
You still can use the 521 and ground fault for tracing the wires and faults....

Does the 521 give you the distance to the fault?

FIMCO-MEISTER
10-08-2007, 08:09 AM
Does the 521 give you the distance to the fault?

May get corrected but the answer from me is no. i actually limit my 521 to tracing, valve locating, and finding clean wire breaks and use the fault finder for wire nicks, bad splices, and narrowing break locations.

londonrain
10-08-2007, 09:42 AM
May get corrected but the answer from me is no. i actually limit my 521 to tracing, valve locating, and finding clean wire breaks and use the fault finder for wire nicks, bad splices, and narrowing break locations.
Peter is correct.....

Kiril
10-08-2007, 09:44 AM
So in your case LR (a 2-wire system you didn't install), would it be beneficially to be able to know the distance, or is it still not enough info to save time?

PurpHaze
10-08-2007, 09:51 AM
Does the 521 give you the distance to the fault?

As Peter and London have stated... no. However, you CAN find the depth of the wire when you're in the area of the ground fault. I've used the triangulation aspect of the 521 many times and if done right it's pretty accurate.

BrandonV
10-08-2007, 10:06 AM
does anyone else use a fault locator like mine? I have a triangluar almost walking stick like product that plugs into my rycom locator, does a alright job. just trace the path and then walk and push the two needles into the ground every so many feet. It really has paid off in a few situations