Munro StartBox MSPR242W22 will it work?

[carguytoo]

I have an old school Munro StartBox MSPR24… Worked great with my old RainBird controller… With Rachio 3, I get intermittent faults when trying to start the pump.

I saw some chatter about the MSPR24 requiring just a little more current that the Rachio can consistently provide and the fault sensor is triggered.

Before I cough up $65 for this Munro, I need to know if it will work. There is no specification for the current level that trips the Rachio fault that I can find anywhere to make this decision.

Help? Thanks

[DLane]

@carguytoo - Another, less expensive option, is to use an external relay and power supply to signal the Munro. See this post for a diagram (just ignore the second Rachio in the diagram that is wired in parallel) →

2 Controllers with Munro Smart Pump Relays. Does it work? Yes / No?

@AngryIrrigationMan - you’re welcome! The current draw isn’t related to the current or voltage (a 220v pump will pull about half the amps a 120 volt pump will for the same size) the pump draws, but rather the current the pump start relay needs to close the relay and energize the pump. Here is a Visio drawing I quickly hacked together. [image] That relay will work. I prefer a sealed unit like -> Let me know if you have any other questions. Again - YMMV.

[carguytoo]

Thanks. I will stare at this over lunch.

[carguytoo]

Ok…to make sure I understand this…

I get a fan relay as indicated

I find a 24 volt power supply that has 1 amp output. Can I just use one with multiple current outputs? 1-5 amps?

I wire this relay to the Rachio so that the controller signal will latch this relay.

I connect the power supply to this relay.

I connect the output of this relay to the control signal input of the Munro relay.

In this way, I will always have enough current to close Old Munro relay

Thanks in advance for clarifying this…

[DLane]

@carguytoo - Yep, you got it. The power supply should be at least 1 amp, higher is fine.

I think it is the initial current inrush when the Munro is being activated when combined with the first zone, is what is causing the brown out event on the Rahcio that will trigger the fault message. This way Rachio won’t see that brown out as the Munro device will have its own power supply.

Yes, if the power supply supports more current e.g. 5 amp that should be fine too.

[carguytoo]

Great. I am ordering the parts Thanks