Hacking the Pentair Jung Pumpen AGR device⌗

My house came with a strange little device called a Pentair Jung Pumpen AGR. Honestly, it might be the most overpriced gadget I’ve ever seen — essentially a passthrough plug with a small leak sensor that triggers a loud alarm.

There’s no configuration, no smart features, and it’s only IP20 rated. Yet somehow, this thing sells for over €300(!).

I’d never paid much attention to it — until recently, when a small leak (thankfully no real damage) set it off. The alarm woke us up in time to clean up before anything serious happened. Nice!

But then I wondered: what if we hadn’t been home? Or if the power had been out?

box

Overpriced Accessories⌗

Of course, there are official accessories — also hilariously overpriced.

  • A €50 9V Ni-MH backup battery
  • A ~€200 EnOcean automation module

At that point I was convinced this thing must be hiding some complicated tech inside.

Inside the Belly of the Beast⌗

When I cracked it open, the reality was… hilariously simple.

It turns out you can just drop in a regular 9V Ni-MH battery. I picked up an Energizer for €7, slotted it in, closed the plastic cover, and voilà — now the AGR runs during power cuts.

battery

Even better, it turns out those mysterious terminals labeled 40 & 41 are just a dry contact relay. When a leak is detected, the pins are simply shorted together.

Which means… perfect for a Shelly!

Adding Smart Monitoring⌗

My finished setup looks something like this:

finished

Wiring⌗

Here’s all it takes to connect the Pentair AGR to a Shelly i4 DC:

       +-------------------+
       |   Shelly i4 DC    |
       |                   |
       |   [ GND ]---------+----------[40] Pentair AGR Alarm
       |                   |
       |   [ SW1 ]---------+----------[41] Pentair AGR Alarm
       |                   |
       +-------------------+

That’s it: when water is detected, the AGR shorts 40 & 41, and the Shelly sees it as a button press on SW1.

Realistically, anything that can detect a button press would work here — a Shelly 1 would be more than enough. I just went with the i4 for the extra inputs and add-on flexibility. The Pentair device provides gromets and cable relief so wiring is pretty easy, I used cat6 flexible ethernet wire because that’s what I had around.

Further Work⌗

I also added an XKC-Y25 capacitive water level sensor to monitor water outside the pump’s plastic tank. Hooking it up was easy using a Shelly add-on (details here).

Shelly also recently started with the Flood 4 device that would probably be worth adding as additional protection and seems reasonably priced — I just wish there was a 12V DC version.