Help with power wiring

I need help making sure I connect the wires correctly for the power. I am guessing the wires on the left are currently powering the control and need to use the same way to power the Rachio gen 3 as I do not have an outlet nearby to use. Thank you.

According to the following line, I am almost positive those terminals marked 24 VAC are for powering (output) sensors, not as input to the controller. What you might want to do is go look at the other end of the power for your old controller and replace it with the Rachio power supply with the cable cut, and splice in the power supply on one end with the connector on the other.

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I am not too for sure where the other end of the power goes to. Theres three cables that go into the box. Two go to the ceiling and one to the ground. The two that go to the ceiling are whats plugged on the left side. I also found these boxes in the back yard that go with the sprinkler system if that tells anything.

Hmmm, the mystery continues . . .

From the original second picture & new first image: I just noticed it looks like you are wanting to replace the Hunter controller, maybe a Pro-C? I apologize if you already knew all this, but it is helping me to understand some things.

Left side of the old controller (starting from top):

  • SEN: Appears you have a weather (rain) sensor hooked (this and next terminal). If I followed it correctly, this the cable going to the ceiling on the right side of the stud.
  • SEN
  • REM: Not hooked up
  • AC2: This and next three come from transformer as 24VAC (this and next terminal) plus ground (last terminal). If I followed it correctly, this the cable going to the ceiling on the left side of the stud.
  • AC1
  • GND: Ground

Right side of the old controller (starting from top). If I followed it correctly, this the cable going to the ground.

  • 6: Zone 6 power
  • 5: Zone 5 power
  • 4: Zone 4 power
  • — next block
  • 3: Zone 3 power
  • 2: Zone 2 power
  • 1: Zone 1 power
  • P/MV: Pump/Master Valve power. Probably goes to the pump start relay
  • COM: Common for all zones and P/MV
  1. Second to last image, “Pump Start Relay”, model PSR-22: I recognize that as a Hunter brand because I have one (using for a water-feature). With how the red wire is hooked to the P/MV, I would guess it is for a pump for the irrigation water or a master valve.
  2. Last image: I am not sure where that switch goes. Does flipping that switch do anything with the power to the controller, outdoor lights, pump to something, any clues you can provide? It does not seem like it would turn on/off the P/MV separate from the controller, but is possible.

Transformer Output (I believe):

  • Hunter: 25 VAC, 1.0 amp
  • Rachio: 24 VAC 1000mA (1.0A)

I would not be 100% comfortable to say that this is close enough. I do not know how much voltage tolerance the Rachio is built with.

It probably would be best to find the transformer no matter what. Is the controller mounted outside, in a garage/carport, shed, house, elsewhere? That might help find the transformer. Are you able to get in any crawl space above that ceiling?

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So you are right about everything. The only thing I can tell about that switch is that the sprinkerls will not go off if its switched off but the controller stays on. The controller is in the garage and I can not get into the crawl space to try and find the transformer.

So woukd it be fine for me to run an extension cord to the Rachio and call it good and not have to worry about the transformer?

In other words, with that switch in the off position, no water comes out of the sprinklers? Interesting. Actually, I wonder if it cuts power to the P/MV instead of doing something with the valve.

For now and to get watering, I probably would use the extension cord. Places to check for the transformer might be in a mechanical room, closet, garage, shed, etc. Do you know where the transformer is for your doorbell?

Yea its in a mechanical room in my basement.

The doorbell transformer is in the mechanical room? Maybe the sprinkler transformer too?

It’s possible that the power to the old controller is coming from the box for the master pump. If you are not that well versed in electrical you might want to have a professional wire the power or wire in a plug next to the new controller otherwise for the short term do what Thomas is suggesting w/ an extension cord but only as a temporary fix. You will want to disconnect the old power wires and you will need to wire in the new transformer for the Rachio(it’s fairly straight forward if you can find the power source for the old controller).

My PSR box does not have enough room for most transformers. I wish I knew the tolerances for Rachio to let you know if you could use the old transformer or not. If you lived close by, which I think you are in OK which is not close by (I am way West), I would offer to come by and help.

@Mightycan - Ideally, I’d do what @Thomas_Lerman suggested - find the Hunter transformer and replace it with the Rachio transformer. To do this one will need to cut the Rachio power cord and splice it into the wires running from the Hunter transformer and then splice the Rachio plug into the end in the garage to plug into the Rachio.

If you can’t find the Hunter transformer or it is hard wired into the electrical system (i.e. not inserted in an electrical plug), I feel confident that one can cut off the Rachio power plug and connect the wires coming from the transformer (there won’t be a connection for the ground wire) to the Rachio plug and it will work.

Let me emphasis that the 24 VAC terminals on the Rachio are not meant to sink (i.e. input) power but rather source (i.e. output) power. I’ve seen posts where others have attached a power supply to the 24 VAC terminals and it blows a component on the Rachio board.

Thank for all the suggestions. I actually found where it is plugged in at by accident. I was installing a smart garage door open and noticed the plug above the garage opener. So would it work if I cut the Rachio plug and splice it together and use the same cable? I’m assuming I would have to to both ends inorder for it to work.

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Ah, of course. It is running up into the space of the garage to come out by that outlet. Great job!!! I am glad you found it. Yes, cut the Rachio cable long enough to connection on both ends (allowing for mistake and recut), reuse the wire your already have run, and spice the transformer by the outlet & the other end by the Rachio. As mentioned, you will not do anything with what was the ground wire. I probably would use red & white and leave green disconnect (kind of the standard colors for things).