SPST Wiring with 24v Transformer wProblem

post by Cindy on Jun 19, 2024

I have installed two Rachios in the past with no problem but they didn’t link to a pump. This time I am trying to replace a Rainbird controller (with a 220v 1 HP pump and Hydrotek 1000 pump start relay) with a Rachio 3. I kept getting the wiring issue error and searched the forum.

I found the instructions from DLane to use a SPST and 24v transformer. I bought the ones he suggested from Amazon (Amazon Transformer) but I am getting a repeated clicking (I think at the pump start relay) about every second or so when I try to run a zone.

I have the Rachio M & C wires connected to the coil leads (#1 & 3) and one wire for the Pump Start Relay is connected to the 24v transformer. The other pump start relay wire is connected to the SPST. The second wire for the 24v transformer is connected to the SPST. I must have something wired wrong?

Can someone please lead me to a working solution before my lawn dries up? I don’t want to have to reinstall the Rainbird. I can attach photos if needed, but nearly all the wires are white so it is difficult to follow from the photo.

Thanks in advance for any assistance you can provide.

post by ady624 on Jun 19, 2024

can you draw a schematic?
the control pins of the single pole single throw (1 and 3) should connect to M and C of Rachio. The other two (2 and 4) pins need to be inline with the pump start relay and the transformer - what power does the pump start relay need to operate? 24VAC? Pump model?

post by Cindy on Jun 19, 2024

Hi ADY624 Thank you for trying to help me. Per the drawing from DLane, the M and C link to the coil connections on the SPST. That is correct, right? the pump start relay is a Hydrotek 1000. How can I tell how much power that needs? The pump model is unknown. It is buried and we have been told you can’t bury them anymore. I know the pump is a 220v 1 HP pump because there is a shut off for it. Please ask more questions. I really appreciate you trying to help!

post by ady624 on Jun 19, 2024

The only thing I could find is this HYDROTEK 1000 INSTALLATION & TROUBLESHOOTING MANUAL Pdf Download
is yours a controller or just a pump start relay? is there any diagram whatsoever on the hydrotek? can you provide some pictures?

post by Cindy on Jun 20, 2024

I apologize for not responding more quickly. My husband just had rotator cuff repair surgery and he needed assistance; then I forgot to come back to you.
The Hydrotek 1000 is only a pump start relay. The controller was a Rainbird ESP-M. Here is a link to its manual, but I didn’t see anything in it that would help. Rain Bird ESP-Modular User Manual
There is also CentriPro Model CB10412 control box that is attached to the Hydrotek. Here is the manual link. 548671_1_Goulds+Quick+Disconnect+Control+Box+Brochure.pdf
But I used the M and C wires from the Rainbird to wire the Rachio (and then the SPST) and those came out of the Hydrotek so I don’t think the CentriPro matters?

I have sketched a schematic. I am no artist, and it’s not to scale but hopefully it helps. I will upload it from my phone.

post by Cindy on Jun 20, 2024

post by ady624 on Jun 20, 2024

I am sorry to hear about your husband and wish him a speedy recovery
Forgive my messy, slanted drawing, pretty good for just having woken up

post by Cindy on Jun 20, 2024

Good morning. Excellent drawing for just waking up! Thank you for the good wishes for my hubby. It’s going to be a very long recovery.
So - Yes, what you show for the low power is what I have and I believe what you show for the high power is what I have. The high power was working fine before Rachio - and I have changed nothing there. I have the M terminal set to Well or Pump Start Relay.

post by ady624 on Jun 20, 2024

So what do you get when turning a zone on? Unplug the transformer so we isolate things, you have a SPST and a DPST (that Hydrotek 1000 is internally a GE double pole single throw relay).
One click for start and one click for end? Or many, many clicks?

post by Cindy on Jun 20, 2024

I get many clicks as currently wired. I will go unplug the transformer and see what happens.

post by Cindy on Jun 20, 2024

Interesting. I don’t get the repetitive clicking, which is wonderful. But the sprinkler also doesn’t run. I tried a couple of zones.

post by ady624 on Jun 20, 2024

well yeah, it is expected to not work, you are not triggering the hydrotek relay. Wire it back up, is the hydrotek the one doing the many clicks? or the pump controller? do not touch wires, those two work on higher voltage that is dangerous.

post by ady624 on Jun 20, 2024

if you cannot determine where the sound is coming from (components too close to each other), you can use a funnel to figure it out, much like a stethoscope- watch your ears though. Top of the funnel against the device, listen through the funnel neck but don’t stick it in your ear, it may be loud. Another way is with touch, but given the high voltage, am skeptical of asking you to touch things in there.

Loudest clicker wins.

post by Cindy on Jun 20, 2024

the HydroTek is loudest

post by ady624 on Jun 20, 2024

I think I know why. According to this General Electric link the coil is 110V, not 24V. Let’s inspect ye old controller, was the hydrotek plugged right up into the COM and M/V ports? I am looking for other sources to confirm that DPST relay is 110V driven, not 24VAC. I believe the enclosure may take 24V and drive the relay.

post by Cindy on Jun 20, 2024

Yes, the old controller had them in the MV and COM ports.

post by ady624 on Jun 20, 2024

I believe that web page is wrong, others say min voltage is 24V. It looks like either that is now broken, or has a higher energy requirement to keep the coil and switch engaged, and the transformer is not providing it, voltage drops and relay disengages, then repeat. You don’t happen to have a voltmeter, do you?

post by Cindy on Jun 20, 2024

Like a multimeter? My hubby has one of those…

post by Cindy on Jun 20, 2024

On the cardstock/paper in the Hydrotek it says 5-HP24V

post by ady624 on Jun 20, 2024

Yeah, that part is long discontinued, cannot find any exact reference, I expect the coil is 24V. The question is, how much power does it draw. Which transformer did you purchase? What is its advertised VA power?

post by Cindy on Jun 20, 2024

24 Volt Doorbell Transformer 110V/120V AC to DC 24V Adapter

post by ady624 on Jun 20, 2024

with the multimeter, you’d want to set it to 200V~ (alternative) and measure the voltage on the two wires going to the HT1000. Do not measure inside the box where there’s 110/220V present - just the wires going to it, one should come from the SPST and the other from the 24V transformer. Only do this if it is safe, please. If not, I’d suggest you get an irrigation guy to take a look at it.

If the HT1000 is broken, you might as well buy a recommended pump start relay and then not need the SPST and the transformer, but we don’t know if it’s broken yet.

post by ady624 on Jun 20, 2024

ok, so the transformer suggests it can put out 1A - when Rachio complained, did it mention any amperage being used? Struggling to find any reference on power need for that HT1000 coil

post by ady624 on Jun 20, 2024

the closest I could find is the new series 1500 from K-Rain - they suggest the coil resistance is either 155Ω for the lower powered ones and 5.6Ω for the higher powered ones. That’s about a 70VA in rush current on startup - which your transformer would not be able to withstand. Nor would the Rachio. Explains the clicking.

post by Cindy on Jun 20, 2024

When Rachio complained? Do you mean the error message? I haven’t gotten it since I started with the SPST work around but it was saying there was a wiring error. I will try to check those wires you requested.

post by ady624 on Jun 20, 2024

I think we need a bigger boat. Sorry, transformer

post by ady624 on Jun 20, 2024

between 40VA and 50VA (note in AC we don’t use W watts, we use VA volt-amps) - I would pick the 50 if the price diff is irrelevant - they both are over the stable 7VA, but it’s likely the 50VA will handle the in-rush split second 60VA power draw at start up easier than the 40VA. We don’t know their in-rush current ratings, but they both should be way over that 60VA. We’re talking about 20-50ms of in-rush currents, they can handle it.

Get the one that arrives faster? LOL

post by Cindy on Jun 21, 2024

Thank you so very much! The new transformer arrived tonight and I hooked it up - and we had water! I really appreciate your time and knowledge getting me on the right path! Have a wonderful weekend!

post by franz on Jun 21, 2024

Nice job @ady624 ! Holy cow.