Unreliable valve wiring... Best way to make connections?

So I have an old sprinkler system that I’ve been maintaining for the past several years. I’ve noticed that my zones are sometimes very unreliable with popping up, and have started looking at the wiring.

Now I’ve found that one of the COM splices was loose or making a bad connection, as if I’d lift up on the wire, the currently running valve would come on. I was trying to replace the twist on connectors that were there with these:

But I’m not sure if they’re making good connection… The solenoids have a much thicker stranded wire (14 gauge?) compared to the (18 gauge?) sprinkler wire, and I’m not sure if these connectors are the right thing to use with mixed wire gauges.

Using these toro solenoids (89-0114):

Wife put down some week killer in the yard, so I wasn’t able to test after making each connection, but right now it seems like most zones are not working. And once the wires are in these connectors, there’s nothing exposed to test with multimeter :frowning:

Any suggestions?

I personally have always used the waterproof wire nuts with no issues, so I can’t speak for the ones you are using. I’d say that they are a very cheap and easy option to rule out the connection…

Otherwise, can you see any cuts or chaffing on the wiring inside the box area?

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Use something like this for your connections.

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@talz13 - what @ronjonp suggested or I’ve used and recommended these:


There is also an equivalent at Lowe’s if they’re closer to you.

An on the multimeter test - do the round trip at the Rachio by taking the wires out of the terminal and testing each zone with one lead and the common on the other lead.

@DLane those are actually what I had put on a couple years ago, and one of the ones I was having trouble with.
I didn’t think about testing from the rachio end of the wires, what would you test with? I wouldn’t want to damage the solenoid at the other end, and they’re way too far away to monitor directly if I have to hold on to the wires at the rachio (rachio is inside the garage, valve boxes are all the way at the far end of the house!)

Use a multimeter, one end on the zone lead, the other on the common wire lead, both at the Rachio.

I’ll set my multimeter to read voltage and check it out tonight, it’ll at least narrow down which ones look good and which ones need work.

Another question on wiring… Looks like the COM is wired in series with all of the zones at the valve end, so if one connection is not reliable, it puts the whole system at risk. Is this the normal way of wiring, or is there a way to wire in parallel so that no single valve impacts the rest of the system?

@talz13 - set the multimeter to Ohms and take the wires out of the Rachio terminal so the wiring from out to the solenoid and back is being tested. As far damaging the solenoid, the solenoids use 24 VAC and the multimeter will probably use one AA battery that is putting out 1.5 V DC to test resistivity - so don’t worry about that. One should see +/- 35 ohms through the coil and wiring.

The solenoids are actually wired in parallel (from an electrical sense). But I understand what you mean on the COM wire and that is the normal way that I’ve see the solenoids wired. There is one common wire in the field bundle and it runs to every solenoid. There is a joint at every solenoid with two ends of the field common wire and one wire to the solenoid.

If the field wire has some unused wires, e.g. four zone and a seven wire field cable, then the two unused field wires could be connected as commons for other solenoids. Or if there is one spare wire in the field wire, I’d connect it to the last solenoid’s common along with the regular common and then place that wire in another C terminal on the Rachio. This way if there is just one faulty common connection only that zone would be impacted as there is a ring for the common. In the current configuration, every zone after a bad connection, and including the zone that has the bad connection, will be impacted.

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Thanks for the write up! I’m currently working on rewiring my valve boxes with some terminal blocks from Lowe’s. I made jumpers from some of my leftover thermostat wire (18 gauge) to connect each of the sections together on the terminal block.

I’ve got:

  • COM from Rachio in to terminal block
  • Each solenoid COM wire is wired to the next open spot on the terminal block
  • Last jumpered section on terminal block is wired to COM wire travelling to next valve box

I might go back and have the in/out COM be the first two spots on the block, just in case there’s ever an issue with the jumpers down the line, but it is working so far, for the first 3 valves that I completed last night. And the screw terminals seem to hold the wires very well.

If it develops moisture related issues in the future, I’ll look into making a waterproof box for it, or look for some kind of marine-type terminal block. But this looks like it might work great for this season at the very least.

@talz13 - one might want to put some petroleum jelly or silicon grease over the terminals to reduce the chance of moisture issues, corrosion or rust.

I could do that. Didn’t think about just coating it with Vaseline or something.
At least each and every zone is coming up reliably right now, and the wiring is much cleaner.