diff --git a/lambda-test/rules-test.c b/lambda-test/rules-test.c
index fd45c15..d3a7d54 100644
--- a/lambda-test/rules-test.c
+++ b/lambda-test/rules-test.c
@@ -82,7 +82,7 @@
 	reason(meas);
 	assertFalse(rules[1].fired);
 
-	meas.tempI = 799;
+	meas.tempI = 699;
 
 	resetRules();
 	dir = firing_up;
@@ -349,8 +349,8 @@
 
 	setHeaterOn(true);
 
-	// more than 3 mins
-	addTime(181);
+	// more than 5 mins
+	addTime(301);
 
 	meas.current = 5000;
 	reason(meas);
@@ -404,31 +404,31 @@
 	reason(meas);
 	assertTrue(dir == firing_up);
 
-	meas.tempI = 790;
+	meas.tempI = 690;
 	meas.lambda = 2000;
 	age = 180;
 	reason(meas);
 	assertTrue(dir == firing_up);
 
-	meas.tempI = 790;
+	meas.tempI = 690;
 	meas.lambda = 2000;
 	age = 180;
 	reason(meas);
 	assertTrue(dir == none);
 
+	meas.tempI = 690;
+	meas.lambda = 1900;
+	age = 180;
+	reason(meas);
+	assertTrue(dir == burning);
+
+	meas.tempI = 700;
+	meas.lambda = 2000;
+	age = 180;
+	reason(meas);
+	assertTrue(dir == burning);
+
 	meas.tempI = 800;
-	meas.lambda = 2000;
-	age = 180;
-	reason(meas);
-	assertTrue(dir == firing_up);
-
-	meas.tempI = 850;
-	meas.lambda = 2000;
-	age = 180;
-	reason(meas);
-	assertTrue(dir == none);
-
-	meas.tempI = 900;
 	meas.lambda = 1999;
 	age = 180;
 	reason(meas);
@@ -466,13 +466,13 @@
 	reason(meas);
 	assertTrue(dir == burning);
 
-	meas.tempI = 700;
+	meas.tempI = 699;
 	meas.lambda = 2000;
 	age = 180;
 	reason(meas);
 	assertTrue(dir == burning_down);
 
-	meas.tempI = 700;
+	meas.tempI = 699;
 	meas.lambda = 2000;
 	age = 180;
 	reason(meas);
diff --git a/lambda-test/sensors-test.c b/lambda-test/sensors-test.c
index e8e55f8..f324958 100644
--- a/lambda-test/sensors-test.c
+++ b/lambda-test/sensors-test.c
@@ -208,6 +208,18 @@
 	return true;
 }
 
+static bool testGetHeaterUptime(void) {
+	addTime(10);
+
+	setHeaterOn(true);
+	assertTrue(0 == getHeaterUptime());
+
+	addTime(10);
+	assertTrue(10 == getHeaterUptime());
+
+	return true;
+}
+
 /* Test "class" */
 static const char class[] PROGMEM = "sensors";
 
@@ -234,6 +246,7 @@
 static const char testToInfoRich_P[] PROGMEM = "testToInfoRich";
 static const char testSetHeaterOn_P[] PROGMEM = "testSetHeaterOn";
 static const char testSetHeaterState_P[] PROGMEM = "testSetHeaterState";
+static const char testGetHeaterUptime_P[] PROGMEM = "testGetHeaterUptime";
 
 /* Tests */
 static TestCase const tests[] = {
@@ -258,7 +271,8 @@
 		{class, testToInfoIdeal_P, testToInfoIdeal},
 		{class, testToInfoRich_P, testToInfoRich},
 		{class, testSetHeaterOn_P, testSetHeaterOn},
-		{class, testSetHeaterState_P, testSetHeaterState}
+		{class, testSetHeaterState_P, testSetHeaterState},
+		{class, testGetHeaterUptime_P, testGetHeaterUptime}
 };
 
 TestClass sensorsClass = {tests, sizeof(tests) / sizeof(tests[0])};
diff --git a/lambda/display.c b/lambda/display.c
index 6d1ad5f..f23e049 100644
--- a/lambda/display.c
+++ b/lambda/display.c
@@ -136,6 +136,7 @@
 				case firing_up: hint = " >"; break;
 				case burning: hint = " ^"; break;
 				case burning_down: hint = " <"; break;
+				case warm_start: hint = " +"; break;
 				default: hint = " -"; break;
 			}
 			displayMeas(measLatest, hint);
diff --git a/lambda/rules.c b/lambda/rules.c
index 11f9c78..26f47b2 100644
--- a/lambda/rules.c
+++ b/lambda/rules.c
@@ -140,7 +140,7 @@
 		return;
 	}
 	if (meas.current > milliAmpsShort || meas.current < milliAmpsDisconn ||
-			(getHeaterUptime() >= 300 && meas.current > milliAmpsReady)) {
+			(getHeaterUptime() >= 300 && getHeaterState() != heaterStateReady)) {
 		// short circuit or disconnected or did not warm up within 5 minutes
 		setHeaterOn(false);
 		setHeaterState(heaterStateFault);
@@ -150,7 +150,7 @@
 }
 
 /**
- * Switches the heater off if it is on for 15 mins or more and there does
+ * Switches the heater off if it is on for 30 mins or more and there does
  * not seem to be a fire, and notifies that the fire is out.
  */
 static void heaterTimeout(bool* const fired, int8_t const dir,
@@ -159,11 +159,11 @@
 		return;
 	}
 	uint32_t heaterUptime = getHeaterUptime();
-	if (heaterUptime >= 900 && meas.tempI < TEMP_FIRE_OUT) {
+	if (heaterUptime >= 1800 && meas.tempI < TEMP_FIRE_OUT) {
 		setHeaterOn(false);
 		alert_P(BEEPS, LENGTH, TONE, PSTR(MSG_FIRE_OUT_0), PSTR(""), false);
 	}
-	if (heaterUptime >= 1800 && meas.tempI < TEMP_AIRGATE_0) {
+	if (heaterUptime >= 3600 && meas.tempI < TEMP_AIRGATE_0) {
 		setHeaterOn(false);
 	}
 }
@@ -225,14 +225,18 @@
 		if ((meas.tempI - rulesMeasPrev.tempI) >= TEMP_DELTA_UP &&
 				rulesMeasMax.tempI < TEMP_MIN && meas.lambda >= LAMBDA_MAX) {
 			dir = firing_up;
-		} else if (meas.tempI > TEMP_MIN || meas.lambda < LAMBDA_MAX) {
+		}
+		if (meas.tempI >= TEMP_MIN || meas.lambda < LAMBDA_MAX) {
 			dir = burning;
-		} else if ((rulesMeasPrev.tempI - meas.tempI) >= TEMP_DELTA_DOWN &&
-				rulesMeasMax.tempI > TEMP_MIN && meas.lambda >= LAMBDA_MAX) {
+		}
+		if ((rulesMeasPrev.tempI - meas.tempI) >= TEMP_DELTA_DOWN &&
+				rulesMeasMax.tempI >= TEMP_MIN && meas.lambda >= LAMBDA_MAX) {
 			dir = burning_down;
-		} else if ((meas.tempI - rulesMeasPrev.tempI) >= TEMP_DELTA_UP) {
+		}
+		if ((meas.tempI - rulesMeasPrev.tempI) >= TEMP_DELTA_UP &&
+				meas.tempI < TEMP_MIN && rulesMeasMax.tempI >= TEMP_MIN) {
 			// it seems wood has been added - reset some measurements and rules
-			// dir = warm_start;
+			dir = warm_start;
 			rulesMeasMax.tempI = meas.tempI;
 			size_t rulesSize = sizeof(rules) / sizeof(rules[0]);
 			for (size_t i = 0; i < rulesSize; i++) {
diff --git a/lambda/rules.h b/lambda/rules.h
index 4b94fea..c191407 100644
--- a/lambda/rules.h
+++ b/lambda/rules.h
@@ -51,6 +51,7 @@
 	none = 0,
 	firing_up = 1,
 	burning = 2,
+	warm_start = 3,
 	burning_down = -1
 } FireDir;