Wi-Fi Control with Shelly Plus Uni

What you will need

The Shelly with the cable attached.
A phone or tablet with the Shelly Smart Control app installed. You can also use manage the device from its local web interface; see the resources at the end of this page.
Access to a 2.4 GHz Wi-Fi network. (The Shelly Plus Uni does not connect to 5 GHz-only Wi-Fi.)
Access to the four buttons on the Softub control panel: Light, Jets, Up, and Down. If one or more buttons don’t work, you can hook up push buttons to the board (see the service manual).

Installation

The Shelly with the connector added should be attached to J10:

Make sure that the pin 1 (the pin closet to the center of the board), is the grey wire.

Configuring the Shelly

1. Add the Shelly to Wi-Fi

Turn on power to the board.
Open the Shelly Smart Control app and add the Shelly Plus Uni as a new device.
Follow the app prompts to connect it to your 2.4 GHz Wi-Fi network. Give it a useful name, such as Softub.

If you need help with this initial pairing, use Shelly’s own setup documentation. Once it is online, return here to set up the board-specific features.

2. Add the temperature sensor

The board provides temperature data to the Shelly as a DHT22 temperature-and-humidity sensor.

In the Shelly device settings, open Add-on peripherals (the label may appear as Peripherals in the web interface).
Enable add-on functionality if the app asks.
Select Add Peripheral, then choose Temperature and Humidity (DHT22).
Save the setting and allow the Shelly to restart if prompted.
When it returns online, verify that a temperature is displayed. You may rename it Softub Temperature.

The temperature unit is configured independently in the Shelly app. The board sends temperature internally in 0.1 °C increments, so a Fahrenheit value in Shelly may occasionally differ from the control-panel value by a small rounding amount.

3. Enable Wi-Fi control on the board

New boards ship with Wi-Fi control disabled. Choose the mode you want in the board service menu:

Hold all four control-panel buttons for 4 seconds to enter the service menu. The display shows PP0 first.
Use Up and Down to find P10 (Wi-Fi mode).
Press Light to edit the value.
Use Up and Down to select the desired mode.
Press Jets to save and return to normal operation.

P10 value	Mode	Best for
`00`	Off	Wi-Fi control disabled
`01`	Default	Monitoring temperature and remotely pressing Jets
`02`	Override	Keeping the tub running while OUT1 is on
`03`	Heat	Letting Shelly automate the temperature
`04`	Enable	Allowing normal heat/filter operation only at selected times

Choose your control mode

Default (`P10 = 01`): monitor temperature and remotely use Jets

Choose Default when you mainly want to see the tub temperature in Shelly and occasionally start the jets remotely.

Every change of OUT1 will turn on the jets for 20 minutes (unless the jets time has been configured differently).

The normal board program remains in charge of heating, filtering, and the Jets timer. When the tub is idle, a Jets-button press starts the usual 20-minute jet cycle. If it is already running, the same press has the same effect as pressing Jets at the control panel.

Override (`P10 = 02`): keep the tub running while Shelly says On

Choose Override when you want the board to run normally, but want Shelly to keep it active for longer than the normal Jets cycle.

OUT1 On keeps the request active.
OUT1 Off returns the board to its normal program.

This is useful for manual control, a timed run, or a schedule. Configure an OUT1 auto-off timer or an OFF schedule so the request ends when you expect. The board still honors its configured maximum temperature and normal safety protections.

Heat (`P10 = 03`): let Shelly automate the temperature

Choose Heat when you want Shelly to decide when to start and stop heating based on the DHT22 temperature shown in the app.

First, set the temperature you want in the Shelly app. Then create two DHT22 temperature actions that control OUT1:

Action	Fahrenheit example	Celsius example
Turn OUT1 On	Temperature is 3 °F below your desired temperature	Temperature is 1.5 °C below your desired temperature
Turn OUT1 Off	Temperature is 2 °F above your desired temperature	Temperature is 1 °C above your desired temperature

For example, to target 100 °F, turn OUT1 on at 97 °F and off at 102 °F. For a 38 °C target, turn OUT1 on at 36.5 °C and off at 39 °C.

To create each action in Shelly, open the DHT22 peripheral, choose Add action, select the temperature condition, and add a local action that controls OUT1 On or Off. Save both actions.

When OUT1 turns off, the board uses the current temperature as its new target. The values above are recommended starting points because they work with the board’s normal behavior; you may use different thresholds if they better fit your setup. The board’s configured minimum/maximum temperature limits and safety protections still apply.

The physical Jets button continues to work normally. Changing the set temperature on the control panel is allowed, but Shelly will update the set temperature again on its next OUT1 Off transition.

Enable (`P10 = 04`): run normal heat and filtering only at selected times

Choose Enable when you want to limit automatic heat and filter activity to certain hours or days.

OUT1 On permits normal automatic heat and filter operation.
OUT1 Off prevents those automatic heat and filter runs.

In the Shelly app, create schedules that turn OUT1 on at the beginning of your permitted window and off at the end. For example, turn it on at 6:00 PM and off at 10:00 PM on the days you want the tub to run.

The physical Jets button still works normally in this mode. If the Jets button is used, a later heat call can continue to the board’s normal set temperature. Press Jets again when you leave the tub if you want to end that run.

Test your setup

After configuration:

Confirm that the DHT22 tile shows a plausible Softub temperature.
Confirm P10 is set to the mode you selected.
In Default mode, change OUT1 once and verify that it has the same effect as pressing Jets.
For another mode, briefly change OUT1 and verify that it produces the expected result described above.

If a test does not behave as expected, set P10 back to 00 to disable Wi-Fi control while you review the setup.

Advanced: use the humidity value to see board status

The DHT22 humidity reading is not actual humidity. In the normal setup it reports 0.0 and can be ignored.

Advanced users can enable P22 in the board service menu to encode board-output status in the humidity value. Add the values for each active output:

Value	Output that is active
16	Pump
8	Lights
2	Heat
1	Filter

For example, a humidity value of 26 means the pump (16), lights (8), and heat (2) are active. This feature is intended for home-automation users and is not needed for normal Shelly app use.

Troubleshooting

Shelly is online, but no temperature appears. Confirm that the DHT22 peripheral was added, then restart the Shelly if the app requested it. Do not add another physical sensor.

Shelly loses Wi-Fi connection inside the Hydromate. The metal enclosure can weaken Wi-Fi reception. Check the Shelly’s signal strength in the app, then consider moving your Wi-Fi access point closer or adding an access point nearby. You can also consider an external antenna, as you will get a stronger signal outside of the circuit board enclosure.

The app temperature is slightly different from the control panel. Confirm that both use the intended unit. Small Fahrenheit rounding differences are expected because the board reports internally in 0.1 °C increments.

The tub is not responding the way you expect. Confirm that OUT1, not OUT2, is being controlled and that P10 matches the mode you intended. Set P10 to 00 if you want to temporarily return to no Wi-Fi control or montitoring.

More information

Softub® is a trademark of Softub, Inc. Devore Electronics is not affiliated with or endorsed by Softub, Inc.