Pump Relay Options

In order to use the Rachio3 controller with a lake pump I didn’t realize that rachio recommends buying a Munro Starter Box Relay that costs $275. I would not have purchased the unit had I known that. Does anyone know of any lower cost relays that will work with the rachio 3 unit? I’ve been told by tech support that it requires a very low mA draw for the 24vac power supply in their controller. I have a 2hp pump and currently a 40 amp relay that has a 24VAC coil but the draw must be too much because all I get is and error message after it tries to pull in the relay. The relay actually latches but drops back out. I like this new controller but not going to spend big bucks on a relay.

The two that I have heard the most about Orbit (available at Home Depot or Lowe’s) and Hunter (which I have, some say it is too much draw, but I am using it for a water feature, not a pump for the sprinklers).

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@John3 - it is a little bit of a jerry rig, but get a separate Single Pole Single Throw 24 VAC relay (SPST) that is normally open (cost should be around $10), another 24 VAC transformer. Wire the Rachio M terminal to the new relay coil and then wire the new power supply through the relay and to the Munro Starter Box Relay. This way the Rachio will power the light weigh stand alone relay and the separate transformer will power the Munro Starter Box Relay.

If you can mount and connect it safely, possibly

Have you used this in a similar application?

Not sure, I could hook up some things but want to make sure the power draw for the 24V coil is low enough to make the Rachio work. If that has been tested somehow then, I can wire up anything to that.

@John3 - this community is littered with posts where I’ve recommended small relays like this to solve other problems.

A relay like →

The small coil doesn’t pull much power and Rachio can handle it.

Thanks but the problem seems to be finding one for a 40amp load. Just wished Rachio would have made people aware of their limitation. I’ve been looking since I posted this and haven’t found one yet. I don’t want to have to try test a whole bunch of options before finding one that works.

@John3 - What I suggested was keeping the original working starter relay and powering that relay with another power supply via the additional relay. I’ll try to find some time to update this post with a schematic to illustrate.

Thanks. That would be helpful.

From my water pressure loss calculations, the drip irrigation system that I’m designing might not have enough water pressure due to elevated planter beds.

I don’t know anything about pumps to increase water pressure. What is recommended for Rachio and what parts do I need?
Forever Grateful,

@John3 - This is what I had in mind:

The separate relay and power supply is used to trigger the Munro circuity. The Rachio can power the coil in the separate relay as it pulls about 120 milliamps and the separate power supply can supply the larger current needed for the Munro relay.

@tcremer - Rachio can trigger a pump using a pump start relay box (available from Home Depot and Lowes), using the M terminal and activating the option in the Rachio app. These pumps are typically 1 HP etc. and will need their own electrical circuit.

What is the source of the water for your drip system - municipal or well? What is the water pressure from the water supply? How much elevation is there to the elevated planter beds? How much flow will be needed during watering?

My lake pump is a 2hp pump that is required to water my 8 yard zones. It’s a 220V 40amp relay. Currently using a GE relay that as I’ve said pulls too much current. I need to check out you schematic suggestion.

Thanks for the clarification. The SPST Relay would be in front of my current relay. I guess it can pull in my relay using the additional 24VAC power supply. I’ll have to mock it up and see if it works with my GE relay. My RainBird system has a 24VAC relay with a 650mA limitation and it worked great for years. So obviously my GE relay draws less than 650mA.

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@John3 - Yes, sorry I thought you already had the Munro Pump Start Relay - so change out where I had Munro with GE. If the RainBird system used mechanical relays for the switching they could source more current than the Rachio system can. Rachio uses electronic components for switching and that can limit how much current can flow through them along with runing everything else.

Water source is municipal water. See attached calculations.

The raised beds are about 5 feet from the ground.
Let me know if you need more information. I thought the pump relay and the pump were two separate products. Am I correct?

I’m easily confused. Are you saying I should get a General Electric Pump Start Relay?
Why are you mentioning RainBird system? My Client has a Rachio.
Thank you

Some topics got mixed together. My thread with DLane was about a lake pump application.

@tcremer - as @John3 said there are multiple topics going on in this thread, he has a GE brand pump start relay that pulls too much current for Rachio to handle and I was providing a way for it to work.

For your drip irrigation situation, I think you’ll have enough pressure to run the drips at a worst case of 31 PSI. That is a worst case PSI and I’m thinking the pressure might actually be higher when installed. Without knowing if there is a pressure regulator and the number and type of emitters no one can offer a precise answer. Many drips will work fine at 30 PSI - misters may need more PSI.

To answer your question, yes a pump and a pump start relay are two separate products. One needs a pump start relay to control/start a pump with a Rachio controller.