diff --git a/lambda-test/adc-test.c b/lambda-test/adc-test.c
index d045816..1ba9d38 100644
--- a/lambda-test/adc-test.c
+++ b/lambda-test/adc-test.c
@@ -15,7 +15,7 @@
 
 /* Module adc */
 
-bool testSetupADC(void) {
+static bool testSetupADC(void) {
 	setupADC();
 
 	// AVCC is set as AREF
@@ -31,7 +31,7 @@
 	return true;
 }
 
-bool testGetVoltage(void) {
+static bool testGetVoltage(void) {
 	initInterrupts();
 	setupADC();
 	setupSleepMode();
diff --git a/lambda-test/alert-test.c b/lambda-test/alert-test.c
index 015b950..e6a621e 100644
--- a/lambda-test/alert-test.c
+++ b/lambda-test/alert-test.c
@@ -14,7 +14,7 @@
 
 /* Module alert */
 
-bool testOscillateBeep(void) {
+static bool testOscillateBeep(void) {
 	extern uint8_t beepCount;
 	extern uint8_t oscCount;
 
@@ -63,7 +63,7 @@
 	return true;
 }
 
-bool testBeep(void) {
+static bool testBeep(void) {
 	extern uint8_t beepCount;
 	extern uint16_t beepLength;
 	extern uint8_t oscCount;
@@ -82,7 +82,7 @@
 	return true;
 }
 
-bool testAlert(void) {
+static bool testAlert(void) {
 	extern uint8_t beepCount;
 	extern uint16_t beepLength;
 	extern uint8_t oscCount;
@@ -102,7 +102,7 @@
 	return true;
 }
 
-bool testCancelAlert(void) {
+static bool testCancelAlert(void) {
 	extern uint8_t beepCount;
 	extern uint16_t beepLength;
 	extern uint8_t oscCount;
diff --git a/lambda-test/command-test.c b/lambda-test/command-test.c
index 145bf32..afa4b7a 100644
--- a/lambda-test/command-test.c
+++ b/lambda-test/command-test.c
@@ -17,7 +17,7 @@
 
 /* Module command */
 
-bool testIsSimulation(void) {
+static bool testIsSimulation(void) {
 	setupPorts();
 	setHeatingOn(false);
 
@@ -34,7 +34,7 @@
 	return true;
 }
 
-bool testIsLogging(void) {
+static bool testIsLogging(void) {
 	assertFalse(isLogging());
 	runCommand("le");
 	assertTrue(isLogging());
@@ -44,7 +44,7 @@
 	return true;
 }
 
-bool testHeating(void) {
+static bool testHeating(void) {
 	setupPorts();
 	setHeatingOn(false);
 
@@ -57,7 +57,7 @@
 	return true;
 }
 
-bool testCycleDisplay(void) {
+static bool testCycleDisplay(void) {
 	extern uint8_t position;
 
 	cancelAlert(true);
diff --git a/lambda-test/display-test.c b/lambda-test/display-test.c
index ce6be96..3535d74 100644
--- a/lambda-test/display-test.c
+++ b/lambda-test/display-test.c
@@ -16,7 +16,7 @@
 
 /* Module display */
 
-bool testCycle(void) {
+static bool testCycle(void) {
 	extern uint8_t position;
 	extern bool updatePending;
 
@@ -48,7 +48,7 @@
 	return true;
 }
 
-bool testCycleCancelAlert(void) {
+static bool testCycleCancelAlert(void) {
 	extern uint8_t position;
 	extern bool updatePending;
 
@@ -66,7 +66,7 @@
 	return true;
 }
 
-bool testUpdateMeas(void) {
+static bool testUpdateMeas(void) {
 	extern bool updatePending;
 	extern Measurement measLatest;
 	extern Measurement measMax; // = {0, 0, 2000};
@@ -106,7 +106,7 @@
 	return true;
 }
 
-bool testResetMeas(void) {
+static bool testResetMeas(void) {
 	extern bool updatePending;
 	extern Measurement measLatest;
 	extern Measurement measMax;
@@ -123,7 +123,7 @@
 	return true;
 }
 
-bool testUpdateDisplayIfPending(void) {
+static bool testUpdateDisplayIfPending(void) {
 	extern bool updatePending;
 
 	updatePending = true;
@@ -134,7 +134,7 @@
 	return true;
 }
 
-bool testUpdateDisplayIfPendingAlertActive(void) {
+static bool testUpdateDisplayIfPendingAlertActive(void) {
 	extern bool updatePending;
 
 	updatePending = true;
@@ -148,7 +148,7 @@
 	return true;
 }
 
-bool testDisplayText(void) {
+static bool testDisplayText(void) {
 	displayText("testDisplayText", "testDisplayTextLineTooLong");
 
 	return true;
diff --git a/lambda-test/integers-test.c b/lambda-test/integers-test.c
index 6d52ebc..41223ad 100644
--- a/lambda-test/integers-test.c
+++ b/lambda-test/integers-test.c
@@ -13,7 +13,7 @@
 
 /* Module integers */
 
-bool testDivRoundNearest(void) {
+static bool testDivRoundNearest(void) {
 	assertTrue(divRoundNearest(4, 2) == 2);
 	assertTrue(divRoundNearest(5, 2) == 3);
 	assertTrue(divRoundNearest(10, 3) == 3);
@@ -21,7 +21,7 @@
 	return true;
 }
 
-bool testDivRoundNearestNumNeg(void) {
+static bool testDivRoundNearestNumNeg(void) {
 	assertTrue(divRoundNearest(-4, 2) == -2);
 	assertTrue(divRoundNearest(-5, 2) == -3);
 	assertTrue(divRoundNearest(-10, 3) == -3);
@@ -29,7 +29,7 @@
 	return true;
 }
 
-bool testDivRoundNearestDenNeg(void) {
+static bool testDivRoundNearestDenNeg(void) {
 	assertTrue(divRoundNearest(4, -2) == -2);
 	assertTrue(divRoundNearest(5, -2) == -3);
 	assertTrue(divRoundNearest(10, -3) == -3);
@@ -37,7 +37,7 @@
 	return true;
 }
 
-bool testDivRoundNearestBothNeg(void) {
+static bool testDivRoundNearestBothNeg(void) {
 	assertTrue(divRoundNearest(-4, -2) == 2);
 	assertTrue(divRoundNearest(-5, -2) == 3);
 	assertTrue(divRoundNearest(-10, -3) == 3);
@@ -45,7 +45,7 @@
 	return true;
 }
 
-bool testDivRoundUp(void) {
+static bool testDivRoundUp(void) {
 	assertTrue(divRoundUp(4, 2) == 2);
 	assertTrue(divRoundUp(5, 2) == 3);
 	assertTrue(divRoundUp(10, 3) == 4);
@@ -53,7 +53,7 @@
 	return true;
 }
 
-bool testDivRoundUpNumNeg(void) {
+static bool testDivRoundUpNumNeg(void) {
 	assertTrue(divRoundUp(-4, 2) == -2);
 	assertTrue(divRoundUp(-5, 2) == -3);
 	assertTrue(divRoundUp(-10, 3) == -4);
@@ -61,7 +61,7 @@
 	return true;
 }
 
-bool testDivRoundUpDenNeg(void) {
+static bool testDivRoundUpDenNeg(void) {
 	assertTrue(divRoundUp(4, -2) == -2);
 	assertTrue(divRoundUp(5, -2) == -3);
 	assertTrue(divRoundUp(10, -3) == -4);
@@ -69,7 +69,7 @@
 	return true;
 }
 
-bool testDivRoundUpBothNeg(void) {
+static bool testDivRoundUpBothNeg(void) {
 	assertTrue(divRoundUp(-4, -2) == 2);
 	assertTrue(divRoundUp(-5, -2) == 3);
 	assertTrue(divRoundUp(-10, -3) == 4);
diff --git a/lambda-test/interrupts-test.c b/lambda-test/interrupts-test.c
index 45fe032..8e7902e 100644
--- a/lambda-test/interrupts-test.c
+++ b/lambda-test/interrupts-test.c
@@ -15,7 +15,7 @@
 
 /* Module interrupts */
 
-bool testSetupPorts(void) {
+static bool testSetupPorts(void) {
 	setupPorts();
 
 	// test that the pull-up resistor for the mouton is enabled
@@ -30,7 +30,7 @@
 	return true;
 }
 
-bool testSetupSleepMode(void) {
+static bool testSetupSleepMode(void) {
 	setupSleepMode();
 
 	// set_sleep_mode(SLEEP_MODE_IDLE);
@@ -41,7 +41,7 @@
 	return true;
 }
 
-bool testInitInterrupts(void) {
+static bool testInitInterrupts(void) {
 	initInterrupts();
 
 	// ADC interrupt enabled
@@ -60,7 +60,7 @@
 	return true;
 }
 
-bool testInitTimers(void) {
+static bool testInitTimers(void) {
 	initTimers();
 
 	// timer0 clock prescaler /64 = 15.625 kHz overflowing every 16.2 ms
@@ -79,7 +79,7 @@
 	return true;
 }
 
-bool testTime(void) {
+static bool testTime(void) {
 	resetTime();
 	assertTrue(getInts() == 0);
 	assertTrue(getTime() == 0);
diff --git a/lambda-test/rules-test.c b/lambda-test/rules-test.c
index c40f504..4205398 100644
--- a/lambda-test/rules-test.c
+++ b/lambda-test/rules-test.c
@@ -11,6 +11,7 @@
 #include "avrjunit.h"
 #include "rules.h"
 #include "alert.h"
+#include "interrupts.h"
 
 extern uint16_t age;
 extern int8_t dir;
@@ -18,7 +19,7 @@
 
 /* Module rules */
 
-bool testAirgate50(void) {
+static bool testAirgate50(void) {
 
 	Measurement meas = {0, 0, 0};
 
@@ -59,7 +60,7 @@
 	return true;
 }
 
-bool testAirgate25(void) {
+static bool testAirgate25(void) {
 
 	Measurement meas = {999, 0, 0};
 
@@ -100,7 +101,7 @@
 	return true;
 }
 
-bool testAirgateClose(void) {
+static bool testAirgateClose(void) {
 
 	Measurement meas = {999, 0, 0};
 
@@ -141,7 +142,7 @@
 	return true;
 }
 
-bool testTooRich(void) {
+static bool testTooRich(void) {
 
 	Measurement meas = {0, 0, 0};
 	dir = 0;
@@ -183,7 +184,7 @@
 	return true;
 }
 
-bool testFireOut(void) {
+static bool testFireOut(void) {
 
 	resetRules();
 	Measurement meas = {0, 0, 0};
@@ -219,46 +220,111 @@
 	return true;
 }
 
-bool testHeatingReady(void) {
+static bool testHeatingReady(void) {
 
 	resetRules();
+	resetTime();
 	Measurement meas = {0, 0, 0};
 	dir = 1;
 
+	setHeatingOn(false);
+	meas.current = 1300;
+	reason(meas);
+	assertTrue(HEATING_OFF == getHeatingState());
 
+	setHeatingOn(true);
+	meas.current = 5000;
+	reason(meas);
+	assertTrue(HEATING_UP == getHeatingState());
+
+	setHeatingOn(true);
+	meas.current = 1300;
+	reason(meas);
+	assertTrue(HEATING_READY == getHeatingState());
 
 	cancelAlert(false);
 
 	return true;
 }
 
-bool testHeatingFault(void) {
+static bool testHeatingFaultNoconn(void) {
 
 	resetRules();
+	resetTime();
 	Measurement meas = {0, 0, 0};
 	dir = 1;
 
-
+	setHeatingOn(true);
+	meas.current = 0;
+	reason(meas);
+	assertTrue(HEATING_FAULT == getHeatingState());
 
 	cancelAlert(false);
 
 	return true;
 }
 
-bool testHeatingTimeout(void) {
+static bool testHeatingFaultShort(void) {
 
 	resetRules();
+	resetTime();
 	Measurement meas = {0, 0, 0};
 	dir = 1;
 
-
+	setHeatingOn(true);
+	meas.current = 8000;
+	reason(meas);
+	assertTrue(HEATING_FAULT == getHeatingState());
 
 	cancelAlert(false);
 
 	return true;
 }
 
-bool testReasonDirBurnUp(void) {
+static bool testHeatingFaultNoheat(void) {
+
+	resetRules();
+	resetTime();
+	Measurement meas = {0, 0, 0};
+	dir = 1;
+
+	setHeatingOn(true);
+
+	// more than 3 mins
+	addInts(INTS_PER_SEC * 181);
+
+	meas.current = 5000;
+	reason(meas);
+	assertTrue(HEATING_FAULT == getHeatingState());
+
+	cancelAlert(false);
+
+	return true;
+}
+
+static bool testHeatingTimeout(void) {
+
+	resetRules();
+	resetTime();
+	Measurement meas = {0, 0, 0};
+	dir = 1;
+
+	setHeatingOn(true);
+
+	// more than 3 hours below 400°C
+	addInts(INTS_PER_SEC * 10800UL);
+
+	meas.tempI = 300;
+	meas.current = 1300;
+	reason(meas);
+	assertTrue(HEATING_OFF == getHeatingState());
+
+	cancelAlert(false);
+
+	return true;
+}
+
+static bool testReasonDirBurnUp(void) {
 
 	resetRules();
 	Measurement meas = {0, 0, 2000};
@@ -314,7 +380,7 @@
 	return true;
 }
 
-bool testReasonDirBurnDown(void) {
+static bool testReasonDirBurnDown(void) {
 
 	resetRules();
 	Measurement meas = {999, 0, 1999};
@@ -374,7 +440,9 @@
 static const char testTooRich_P[] PROGMEM = "testTooRich";
 static const char testFireOut_P[] PROGMEM = "testFireOut";
 static const char testHeatingReady_P[] PROGMEM = "testHeatingReady";
-static const char testHeatingFault_P[] PROGMEM = "testHeatingFault";
+static const char testHeatingFaultNoconn_P[] PROGMEM = "testHeatingFaultNoconn";
+static const char testHeatingFaultShort_P[] PROGMEM = "testHeatingFaultShort";
+static const char testHeatingFaultNoheat_P[] PROGMEM = "testHeatingFaultNoheat";
 static const char testHeatingTimeout_P[] PROGMEM = "testHeatingTimeout";
 static const char testReasonDirBurnUp_P[] PROGMEM = "testReasonDirBurnUp";
 static const char testReasonDirBurnDown_P[] PROGMEM = "testReasonDirBurnDown";
@@ -387,7 +455,9 @@
 		{class, testTooRich_P, testTooRich},
 		{class, testFireOut_P, testFireOut},
 		{class, testHeatingReady_P, testHeatingReady},
-		{class, testHeatingFault_P, testHeatingFault},
+		{class, testHeatingFaultNoconn_P, testHeatingFaultNoconn},
+		{class, testHeatingFaultShort_P, testHeatingFaultShort},
+		{class, testHeatingFaultNoheat_P, testHeatingFaultNoheat},
 		{class, testHeatingTimeout_P, testHeatingTimeout},
 		{class, testReasonDirBurnUp_P, testReasonDirBurnUp},
 		{class, testReasonDirBurnDown_P, testReasonDirBurnDown}
diff --git a/lambda-test/sensors-test.c b/lambda-test/sensors-test.c
index eb57a3e..95679e1 100644
--- a/lambda-test/sensors-test.c
+++ b/lambda-test/sensors-test.c
@@ -26,7 +26,7 @@
 
 /* Module sensors */
 
-bool testMeasure(void) {
+static bool testMeasure(void) {
 	setupADC();
 	setupSleepMode();
 	initInterrupts();
@@ -55,7 +55,7 @@
 	return true;
 }
 
-bool testReadMeas(void) {
+static bool testReadMeas(void) {
 	char* fields[] = {"1", "2", "3", "4"};
 
 	Measurement meas = readMeas(fields, 4);
@@ -67,7 +67,7 @@
 	return true;
 }
 
-bool testReadMeasTooFewFields(void) {
+static bool testReadMeasTooFewFields(void) {
 	char* fields[] = {"1"};
 
 	Measurement meas = readMeas(fields, 1);
@@ -79,91 +79,91 @@
 	return true;
 }
 
-bool testToLambdaValue(void) {
+static bool testToLambdaValue(void) {
 	uint16_t lambda = toLambda(132);
 
 	return lambda == 1500;
 }
 
-bool testToLambdaInter(void) {
+static bool testToLambdaInter(void) {
 	uint16_t lambda = toLambda(550);
 
 	return lambda == 1073;
 }
 
-bool testToTempI(void) {
+static bool testToTempI(void) {
 	int16_t temp = toTempI(100);
 
 	return temp == 20;
 }
 
-bool testToTempOValue(void) {
+static bool testToTempOValue(void) {
 	int16_t temp = toTempO(454);
 
 	return temp == 0;
 }
 
-bool testToTempOInter(void) {
+static bool testToTempOInter(void) {
 	int16_t temp = toTempO(929);
 
 	return temp == 50;
 }
 
-bool testToCurrent(void) {
+static bool testToCurrent(void) {
 	uint16_t current = toCurrent(150);
 
 	return current == 1500 / SHUNT_MILLIOHMS * 100;
 }
 
-bool testLookupLinInterBelow(void) {
+static bool testLookupLinInterBelow(void) {
 	int16_t value = lookupLinInter(0, testTable, 2);
 
 	return value == 10;
 }
 
-bool testLookupLinInterAbove(void) {
+static bool testLookupLinInterAbove(void) {
 	int16_t value = lookupLinInter(30, testTable, 2);
 
 	return value == 20;
 }
 
-bool testLookupLinInterValue(void) {
+static bool testLookupLinInterValue(void) {
 	int16_t value = lookupLinInter(10, testTable, 2);
 
 	return value == 10;
 }
 
-bool testLookupLinInterInter(void) {
+static bool testLookupLinInterInter(void) {
 	int16_t value = lookupLinInter(15, testTable, 2);
 
 	return value == 15;
 }
 
-bool testLinADCLow(void) {
+static bool testLinADCLow(void) {
 	int32_t lin = linADC(1000);
 
 	return lin == 1004;
 }
 
-bool testLinADCMid(void) {
+static bool testLinADCMid(void) {
 	int32_t lin = linADC(2000);
 
 	return lin == 2000;
 }
 
-bool testLinADCHigh(void) {
+static bool testLinADCHigh(void) {
 	int32_t lin = linADC(4000);
 
 	return lin == 3992;
 }
 
-bool testToInfoLean(void) {
+static bool testToInfoLean(void) {
 	char* info = toInfo(191);
 
 	return ! strcmp(info, MSG_LEAN);
 }
 
-bool testToInfoOkay(void) {
+static bool testToInfoOkay(void) {
 	assertTrue(0 == strcmp(toInfo(190), MSG_OKAY));
 	assertTrue(0 == strcmp(toInfo(170), MSG_OKAY));
 	assertTrue(0 == strcmp(toInfo(151), MSG_OKAY));
@@ -171,7 +171,7 @@
 	return true;
 }
 
-bool testToInfoIdeal(void) {
+static bool testToInfoIdeal(void) {
 	assertTrue(0 == strcmp(toInfo(150), MSG_IDEAL));
 	assertTrue(0 == strcmp(toInfo(140), MSG_IDEAL));
 	assertTrue(0 == strcmp(toInfo(130), MSG_IDEAL));
@@ -179,13 +179,13 @@
 	return true;
 }
 
-bool testToInfoRich(void) {
+static bool testToInfoRich(void) {
 	char* info = toInfo(129);
 
 	return ! strcmp(info, MSG_RICH);
 }
 
-bool testSetHeatingOn(void) {
+static bool testSetHeatingOn(void) {
 	setHeatingOn(true);
 	assertTrue(isHeatingOn());
 	assertTrue(HEATING_UP == getHeatingState());
@@ -197,7 +197,7 @@
 	return true;
 }
 
-bool testSetHeatingState(void) {
+static bool testSetHeatingState(void) {
 	setHeatingOn(false);
 	assertFalse(isHeatingOn());
 	assertTrue(HEATING_OFF == getHeatingState());
diff --git a/lambda-test/strings-test.c b/lambda-test/strings-test.c
index 1d44f51..4ae4297 100644
--- a/lambda-test/strings-test.c
+++ b/lambda-test/strings-test.c
@@ -14,7 +14,7 @@
 
 /* Module strings */
 
-bool testSplit(void) {
+static bool testSplit(void) {
 	char string[] = "f1 f2  f3 ";
 	char* fields[4];
 	split(string, " ", fields, 4);
@@ -27,7 +27,7 @@
 	return true;
 }
 
-bool testSplitSizeTooSmall(void) {
+static bool testSplitSizeTooSmall(void) {
 	char string[] = "f1 f2";
 	char* fields[1];
 	split(string, " ", fields, 1);
diff --git a/lambda-test/usart-test.c b/lambda-test/usart-test.c
index 4e1324e..d1a0619 100644
--- a/lambda-test/usart-test.c
+++ b/lambda-test/usart-test.c
@@ -14,7 +14,7 @@
 
 /* Module usart */
 
-bool testInitUSART(void) {
+static bool testInitUSART(void) {
 	assertTrue(BAUD);
 
 	initUSART();