# VThermo + Sonoff TRV + temp sensor

**URL:** https://community.homey.app/t/vthermo-sonoff-trv-temp-sensor/156355
**Category:** Apps
**Created:** [June 19, 2026, 7:41pm UTC](https://community.homey.app/t/vthermo-sonoff-trv-temp-sensor/156355 "2026-06-19T19:41:20Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![matttttt](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/matttttt/32/122713_2.png) [@matttttt](https://community.homey.app/u/matttttt)
#### Post date: [June 19, 2026, 7:41pm UTC](https://community.homey.app/t/vthermo-sonoff-trv-temp-sensor/156355/1 "2026-06-19T19:41:20Z")

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Hello everyone,

I’ve been trying to understand how to set up the Sonoff’s TRV+external termometer with the use of VThermo app, but i’m struggling a lot.

This is how it looks like now in two separate rooms:

 ![image](https://us1.discourse-cdn.com/flex025/uploads/athom/original/3X/b/4/b4d714925f4e2ec89e46951554afed54e8e641f3.png)

For instance in the living room if the radiator TRV with its internal temp. is showing 21.6C and the external temp sensor is showing 22.7 C, where is it taking 22.1C from ?!

That’s just for starters. What i’m truly after is a system that would keep certain temperature e.g. 19C, it would ude the external temp. sensor to measure room temp, and will then send a TURN ON signal to SONOFF’s relay that controls my boiler to turn ON and later OFF the boiler.

please help

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<div class="post-metadata">

### Author: ![qawsedrf57](https://sea1.discourse-cdn.com/flex025/user_avatar/community.homey.app/qawsedrf57/32/123371_2.png) [@qawsedrf57](https://community.homey.app/u/qawsedrf57)
#### Post date: [June 20, 2026, 12:27am UTC](https://community.homey.app/t/vthermo-sonoff-trv-temp-sensor/156355/2 "2026-06-20T00:27:30Z")

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The 22.1 is average from the other 2 temperature.

Use the flowchart state on/off to build a flow to turn on/off youre relay.