diff --git a/docs/12.HardwareSONOFF.md b/docs/12.HardwareSONOFF.md
index 6cf62a3e..c82bb86b 100644
--- a/docs/12.HardwareSONOFF.md
+++ b/docs/12.HardwareSONOFF.md
@@ -1,23 +1,45 @@
-BrewPiLess can run on [SONOFF Basic](https://www.itead.cc/wiki/Sonoff) and [SONOFF TH10/16](https://www.itead.cc/wiki/Sonoff_TH_10/16). You will need to solder the header pins for the first flashing and install temperature sensors. However, because of the small 1M byte flash memory, you will either sacrifice 
+# General
+
+BrewPiLess can run on many different Sonoff devices. You will need to solder the header pins for the first flashing and install temperature sensors.
+
+## Sonoff Basic, Sonoff TH10/16
+
+Sonoff Basic and Sonoff TH10/16 use an ESP8266. Because of the small 1M byte flash memory, you will either sacrifice
+
 * OTA web update for log storage, or
 * 500k log storage for OTA update
-* LCD is not available.
 
-SONOFF dual is not supported, because the Relays are controlled by Serial instead of GPIO.Instead, SONOFF Dual **R2** should work by specify correct PINs.
+LCD is not available.
+
+Sonoff Dual is not supported, because the Relays are controlled by Serial instead of GPIO. Instead, SONOFF Dual **R2** should work by specify correct PINs.
 
 Please note that some older SONOFFs, maybe before 2018, use ESP8266 while new ones use ESP8285. Right configuration must be used.
 
-### ESP32 SonOff devices (Sonoff TH Origin and Sonoff TH Elite)
+## Sonoff TH Elite, Sonoff TH Origin
+
+Sonoff TH Elite and Sonoff TH Origin use an ESP32.
+
+For Sonoff TH Elite the built-in LCD display can be removed and a OLED LCD screen can be connected in its place. Use electrical tape to make sure that the LCD pcb is not touching the main pcb. The front glass is a thin plastic be gentle with it.
+
+### Relay pins
+
+* 16A devices (THR316 and THR316D): 21
+* 20A devices (THR320 and THR320D): 19 (SET) and 22 (RESET)
+
+The 20A devices use a latching relay that requires two pins to set and reset the relay. Configure both pins 19 and 22 for the specific function.
+
+![Configuration Sonoff THR320](image/sonoff_thr320_configuration.png)
+
+### Connecting sensor
+
+The sensor that has the RJ9 connector comes with a controller in the wire that needs to be removed:
 
-For Sonoff TH Elite the built-in lcd display can be removed and a OLED LCD screen can be connected in it's place.. Use electrical tape to make sure that the LCD pcb is not touching the main pcb. The front glass is a thin plastic be gentle with it. 
+* Option 1: Remove the controller and reconnect the wires.
+* Option 2: Use `Sonoff AL010 2.5mm Audio Jack to RJ9 Adapter` with the old sensor using the audio jack conntector.
 
-#### Conntecting sensor
-The sensor that has the RJ9 connector comes with a controller in the wire that needs to be removed
-Option 1: Remove the controller and reconntect the wires (not tested).
-Option 2: Use  `Sonoff AL010 2.5mm Audio Jack to RJ9 Adapter` with the old sensor using the audio jack conntector.
+### Connecting OLED LCD (optional)
 
-##### Connecting OLED LCD (optional)
-* Connect SDA to WR solder pad
-* Connect SCL to CS solder pad
-* Use hotglue over soldered contacts so that you don't ripoff the solder pads accidentally. 
-* Connect 3v and Gnd to corresponding solderpads
+1. Connect SDA to WR solder pad.
+1. Connect SCL to CS solder pad.
+1. Use hotglue over soldered contacts so that you don't ripoff the solder pads accidentally.
+1. Connect 3V and GND to corresponding solderpads.
diff --git a/docs/image/sonoff_thr320_configuration.png b/docs/image/sonoff_thr320_configuration.png
new file mode 100644
index 00000000..a80d02a3
Binary files /dev/null and b/docs/image/sonoff_thr320_configuration.png differ
diff --git a/platformio.ini b/platformio.ini
index 136747fb..cd5f50f5 100644
--- a/platformio.ini
+++ b/platformio.ini
@@ -140,7 +140,7 @@ build_flags =
 monitor_speed = 115200
 lib_deps = ${common_env_data.lib_deps_external_esp32} 
 
-[env:esp32-sonoff]  # for newgen sonoff devices like sonoff elite and origin
+[env:sonoff-thr316] # Sonoff TH Elite 16A (THR316D) and Sonoff TH Origin 16A (THR316)
 platform = ${common_env_data.esp32_framework}
 board = esp32dev
 framework = arduino
@@ -157,6 +157,27 @@ build_flags =
     -DEnableBME280Support=false
     -DSONOFF_NEWGEN=true
 
+monitor_speed = 115200
+lib_deps = ${common_env_data.lib_deps_external_esp32}
+
+
+[env:sonoff-thr320] # Sonoff TH Elite 20A (THR320D) and Sonoff TH Origin 20A (THR320)
+platform = ${common_env_data.esp32_framework}
+board = esp32dev
+framework = arduino
+board_build.mcu = esp32
+lib_extra_dirs = ${common_env_data.esp32_lib}
+
+board_build.partitions = ./partition2.csv
+
+build_flags =
+    -DOLED_LCD=true 
+    -DSerialDebug=false
+    -DEnableHumidityControlSupport=false
+    -DEanbleParasiteTempControl=false
+    -DEnableBME280Support=false
+    -DSONOFF_NEWGEN=true -DSONOFF_THR320
+
 monitor_speed = 115200
 lib_deps = ${common_env_data.lib_deps_external_esp32} 
 
diff --git a/src/ActuatorArduinoPin.h b/src/ActuatorArduinoPin.h
index 89450a5b..f431b54b 100644
--- a/src/ActuatorArduinoPin.h
+++ b/src/ActuatorArduinoPin.h
@@ -9,6 +9,11 @@
 
 #include "Actuator.h"
 
+#ifdef SONOFF_THR320
+#define LATCH_PIN_SET 22
+#define LATCH_PIN_RESET 19
+#endif
+
 template<uint8_t pin, bool invert>
 class DigitalConstantPinActuator ACTUATOR_BASE_CLASS_DECL
 {
@@ -47,7 +52,20 @@ class DigitalPinActuator ACTUATOR_BASE_CLASS_DECL
 
 	inline ACTUATOR_METHOD void setActive(bool active) {
 		this->active = active;
+
+		#ifdef SONOFF_THR320
+		if (active) {
+			digitalWrite(LATCH_PIN_SET, HIGH);
+			delay(10);
+			digitalWrite(LATCH_PIN_SET, LOW);
+		} else {
+			digitalWrite(LATCH_PIN_RESET, HIGH);
+			delay(10);
+			digitalWrite(LATCH_PIN_RESET, LOW);
+		}
+		#else
 		digitalWrite(pin, active^invert ? HIGH : LOW);
+		#endif
 	}
 
 	bool isActive() { return active; }
diff --git a/src/Config.h b/src/Config.h
index 8d73fc7b..92d7e5da 100644
--- a/src/Config.h
+++ b/src/Config.h
@@ -356,11 +356,11 @@
 
 #define oneWirePin 25
 
-#define actuatorPin1  21  // This is relay 1
+#define actuatorPin1  21  // Relay 1 in 16A versions
 #define actuatorPin2  23  // TM1621 RD
 #define actuatorPin3  5   // TM1621 DAT
-#define actuatorPin4  24  
-#define actuatorPin5  26
+#define actuatorPin4  19  // Relay 1 in 20A versions. Latching relay needs 2 pins
+#define actuatorPin5  22  // Relay 1 in 20A versions
 #else // SONOFF_NEWGEN ends
 
 #define PIN_SDA 21