Power Question - replacing Hunter PC-300i

I’m in the process of replacing a Hunter PC-300i (with a rain sensor) with a Rachio 3 and have a question on power wiring. I’ve seen several posts here describing how you don’t need to worry about the Hunter’s “AC1”, “AC2” and “GND” wires because the Rachio will power the system through the system power cord. However, in those posts I’ve seen only a single wire on each of those terminals. On my current system, there are two wires each on the AC1 and AC2 terminals (see picture). One of each of these is a yellow coming from the power plug/transformer while the other two (one white and one red) go over to the other side of the box and down into the tube from which all the zone wires come out.

My question is whether the second wires (that go down into the main tube) are possibly providing some power to the pump relay (or valves?) beyond that supplied through the P/MV or C terminals.

The rest of the set up will be very straight forwards (I did this already once but didn’t have the same set up on the old Rainbird controller that time). Thanks for any help you might be able to provide.

I always suggest making sure you get the system working without the rain sensor first. Many people (definitely not all) find that with the Weather Intelligence, they do not need the sensor as that is either it rained or not, does not take into account how much. You can always hook it up later.

The power from the Hunter transformer DOES NOT get hooked up to Rachio. The other set of wires are likely going to the rain sensor to power that. I know you brought up a pump or master valve. Do you have one of them? I do not think I have seen either with auxiliary power that comes from a controller. I will say that it is a bit hard to tell where some of the wires are going in your pictures. However, I believe, after looking at the pictures a little close, some of the wires are going to a remote unit which you will not use.

The rain sensor does get hooked up differently to the Rachio and need to know the model (I see the model in one of your pictures). For that information, please see Rain Sensors FAQ.

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Thanks for the information and recommendations…yes, I was thinking of removing the rain sensor and mounting it next to the Rachio box since the wiring is pretty logical. I think you might be right about the two extra wires on the AC1 and AC2 coming around to power the sensor - I didn’t pull them out and maybe they are just folded a bit and stuffed into the tube to keeps things “neat”. I’ll trace all the wires in and out of the sensor and see if that’s the answer.

I updated some things in my previous comment I think before you responded, not sure if you saw the old or new comment. The power might be going to the Hunter remote controller.

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Hi again - thanks for the update - yes, there is a wire connected to the REM terminal, but I don’t believe there is a remote control currently used on the system. I assume that would be a handheld remote control device? It’s at my in-laws old house and I don’t think we have any remotes around. I was planning on just using a small wire nut on that wire and leaving it be since it isn’t needed/doesn’t work with the Rachio.

Yes, the REM terminal goes to a remote control device (or at least to their “SmartPort”) that you might not have. From what I have seen, red & white goes to power and blue goes to REM. Information about it may be found at manual_Roam_INT-788-EN.pdf (hunterindustries.com). You are correct, it should not be connected to the Rachio. Putting wire nuts on it might be good just to protect it (maybe even label what they were for).

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Hi Thomas - just wanted to let you know that I got everything running fine - ended up not using the rain sensor though I kept it in case it ever is needed. Was left with three wires including the brown remote and two wires which had been hooked to the 24v terminals on the Hunter. I just sealed these with wire caps and left them in the box. The power wires seem to go down into the conduit so I’m still not 100% sure what they did/do (some power for the remote that is not powered by the control box?) but the Rachio is working fine on all zones and schedules. Thanks again for your help with this.

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Sounds great, good work

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