diff --git a/lambda-test/rules-test.c b/lambda-test/rules-test.c
index 2d5903b..1dcc8d8 100644
--- a/lambda-test/rules-test.c
+++ b/lambda-test/rules-test.c
@@ -188,7 +188,6 @@
 	return true;
 }
 
-/*
 static bool testTooRich(void) {
 
 	Measurement meas = {0, 0, 0, 0};
@@ -217,24 +216,23 @@
 	meas.tempI = TEMP_FIRE_OUT + 1;
 	meas.lambda = LAMBDA_TOO_RICH - 1;
 	resetRules(true);
-	airgate = 100;
+	airgate = 50;
 	reason(meas);
 	assertFalse(rules[3].fired);
-	assertTrue(100 == airgate);
+	assertTrue(50 == airgate);
 
 	meas.tempI = TEMP_FIRE_OUT + 1;
 	meas.lambda = LAMBDA_TOO_RICH - 1;
 	resetRules(true);
-	airgate = 50;
+	airgate = 25;
 	reason(meas);
 	assertTrue(rules[3].fired);
-	assertTrue(100 == airgate);
+	assertTrue(50 == airgate);
 
 	cancelAlert(false);
 
 	return true;
 }
-*/
 
 static bool testTooLean(void) {
 
@@ -253,14 +251,14 @@
 	meas.lambda = 1300;
 	resetRules(true);
 	reason(meas);
-	assertFalse(rules[3].fired);
+	assertFalse(rules[4].fired);
 
 	meas.tempI = TEMP_AIRGATE_50 + 1;
 	meas.lambda = LAMBDA_TOO_LEAN + 1;
 	resetRules(true);
 	airgate = 50;
 	reason(meas);
-	assertFalse(rules[3].fired);
+	assertFalse(rules[4].fired);
 	assertTrue(50 == airgate);
 
 	meas.tempI = TEMP_AIRGATE_50 + 1;
@@ -268,7 +266,7 @@
 	resetRules(true);
 	airgate = 100;
 	reason(meas);
-	assertTrue(rules[3].fired);
+	assertTrue(rules[4].fired);
 	assertTrue(50 == airgate);
 
 	cancelAlert(false);
@@ -285,27 +283,27 @@
 	meas.tempI = 50;
 	age = 0;
 	reason(meas);
-	assertFalse(rules[4].fired);
+	assertFalse(rules[5].fired);
 
 	meas.tempI = TEMP_FIRE_OUT;
 	age = 0;
 	reason(meas);
-	assertFalse(rules[4].fired);
+	assertFalse(rules[5].fired);
 
 	meas.tempI = TEMP_FIRE_OUT_RESET;
 	age = 0;
 	reason(meas);
-	assertFalse(rules[4].fired);
+	assertFalse(rules[5].fired);
 
 	meas.tempI = TEMP_FIRE_OUT - 1;
 	age = 0;
 	reason(meas);
-	assertTrue(rules[4].fired);
+	assertTrue(rules[5].fired);
 
 	meas.tempI = TEMP_FIRE_OUT_RESET;
 	age = 0;
 	reason(meas);
-	assertFalse(rules[4].fired);
+	assertFalse(rules[5].fired);
 
 	cancelAlert(false);
 
@@ -324,7 +322,7 @@
 	reason(meas);
 	assertTrue(50 == airgate);
 	assertTrue(heaterStateOff == getHeaterState());
-	assertFalse(rules[5].fired);
+	assertFalse(rules[6].fired);
 
 	age = 0;
 	dir = firing_up;
@@ -333,7 +331,7 @@
 	reason(meas);
 	assertTrue(100 == airgate);
 	assertTrue(heaterStateUp == getHeaterState());
-	assertTrue(rules[5].fired);
+	assertTrue(rules[6].fired);
 
 	cancelAlert(false);
 
@@ -566,7 +564,7 @@
 static const char testAirgate50_P[] PROGMEM = "testAirgate50";
 static const char testAirgate25_P[] PROGMEM = "testAirgate25";
 static const char testAirgateClose_P[] PROGMEM = "testAirgateClose";
-// static const char testTooRich_P[] PROGMEM = "testTooRich";
+static const char testTooRich_P[] PROGMEM = "testTooRich";
 static const char testTooLean_P[] PROGMEM = "testTooLean";
 static const char testFireOut_P[] PROGMEM = "testFireOut";
 static const char testWarmStart_P[] PROGMEM = "testWarmStart";
@@ -584,7 +582,7 @@
 		{class, testAirgate50_P, testAirgate50},
 		{class, testAirgate25_P, testAirgate25},
 		{class, testAirgateClose_P, testAirgateClose},
-		// {class, testTooRich_P, testTooRich},
+		{class, testTooRich_P, testTooRich},
 		{class, testTooLean_P, testTooLean},
 		{class, testFireOut_P, testFireOut},
 		{class, testWarmStart_P, testWarmStart},
diff --git a/lambda/messages.h b/lambda/messages.h
index 7c16f89..20f1e27 100644
--- a/lambda/messages.h
+++ b/lambda/messages.h
@@ -27,8 +27,6 @@
 	#define MSG_AIRGATE_50_0 "Air gate 50%"
 	#define MSG_AIRGATE_25_0 "Air gate 25%"
 	#define MSG_AIRGATE_CLOSE_0 "Close air gate"
-	#define MSG_TOO_RICH_0 "Too rich, open"
-	#define MSG_TOO_RICH_1 "air gate"
 	#define MSG_FIRE_OUT_0 "Fire out?"
 	#define MSG_HEATER_UP_0 "Oxygen sensor"
 	#define MSG_HEATER_UP_1 "heating up..."
@@ -56,8 +54,6 @@
 	#define MSG_AIRGATE_50_0 "Luftschieber 50%"
 	#define MSG_AIRGATE_25_0 "Luftschieber 25%"
 	#define MSG_AIRGATE_CLOSE_0 "Luftschieber zu"
-	#define MSG_TOO_RICH_0 "Zu fett, Luft-"
-	#define MSG_TOO_RICH_1 "schieber oeffnen"
 	#define MSG_FIRE_OUT_0 "Feuer aus?"
 	#define MSG_HEATER_UP_0 "Lambdasonde"
 	#define MSG_HEATER_UP_1 "waermt auf..."
diff --git a/lambda/rules.c b/lambda/rules.c
index 59f85d8..4fcddad 100644
--- a/lambda/rules.c
+++ b/lambda/rules.c
@@ -69,27 +69,27 @@
 }
 
 /**
- * Notifies that the combustion is too rich and suggests to open the air gate.
- * Disabled because it does not seem to be a good idea to give more air when
- * the combustion is rich as this doesn't really make it leaner and more heat
- * appears to be thrown out through the chimney.
+ * Notifies that combustion is (too) rich and suggests to set the air gate
+ * to 50%.
+ * It does however not seem to be a good idea to fully open the air gate as
+ * this doesn't	make it noticeably leaner, but since the temperature of the
+ * exhaust gas going into the chimney rises, more heat appears to be thrown
+ * out of the chimney.
  */
-/*
 static void tooRich(bool* const fired, int8_t const dir,
 		Measurement const meas) {
 	if (meas.tempI > TEMP_FIRE_OUT &&
 			meas.lambda < LAMBDA_TOO_RICH &&
-			getHeaterState() == heaterStateReady && airgate < 100) {
-		airgate = 100;
-		alert_P(BEEPS, LENGTH, TONE,
-				PSTR(MSG_TOO_RICH_0), PSTR(MSG_TOO_RICH_1), false);
+			getHeaterState() == heaterStateReady && airgate < 50) {
+		airgate = 50;
+		alert_P(BEEPS, LENGTH, TONE, PSTR(MSG_AIRGATE_50_0), PSTR(""), false);
 		*fired = true;
 	}
 }
-*/
 
 /**
- * Notifies that the combustion is lean (again) and to set the air gate to 50%.
+ * Notifies that the combustion is lean (again) and suggests to set the air
+ * gate to 50%.
  */
 static void tooLean(bool* const fired, int8_t const dir,
 		Measurement const meas) {
@@ -215,7 +215,7 @@
 		{false, airgate50},
 		{false, airgate25},
 		{false, airgateClose},
-		// {false, tooRich},
+		{false, tooRich},
 		{false, tooLean},
 		{false, fireOut},
 		{false, warmStart}
diff --git a/lambda/rules.h b/lambda/rules.h
index c0b78c4..6285921 100644
--- a/lambda/rules.h
+++ b/lambda/rules.h
@@ -41,7 +41,7 @@
 /** Fire is considered fully burning if lambda is below this value */
 #define LAMBDA_BURNING 1900
 /** Combustion is considered too rich if lambda is below this value */
-#define LAMBDA_TOO_RICH 1200
+#define LAMBDA_TOO_RICH 1100
 /**
  * Combustion is considered too lean if lambda is above this value
  * Too lean here rather means lean enough so the air gate can be set to 50%