diff --git a/Arduino/BTCDieselHeater/BTCDieselHeater.ino b/Arduino/BTCDieselHeater/BTCDieselHeater.ino
index 2b9c861..661f5a6 100644
--- a/Arduino/BTCDieselHeater/BTCDieselHeater.ino
+++ b/Arduino/BTCDieselHeater/BTCDieselHeater.ino
@@ -139,7 +139,7 @@ void initBlueWireSerial();
 bool validateFrame(const CProtocol& frame, const char* name);
 void checkDisplayUpdate();
 void checkTimer();
-void checkTimer(const DateTime& now, sTimer timerInfo);
+void checkTimer(int timer, const DateTime& now);
 void checkDebugCommands();
 
 // DS18B20 temperature sensor support
@@ -950,32 +950,44 @@ void checkTimer()
 {
   const DateTime& now = getCurrentTime();
 
-  sTimer timerInfo;
-  // test timer 1
-  NVstore.getTimerInfo(0, timerInfo);
-  checkTimer(now, timerInfo);
-  // test timer 2
-  NVstore.getTimerInfo(1, timerInfo);
-  checkTimer(now, timerInfo);
+  checkTimer(0, now);   // test timer 1
+  checkTimer(1, now);   // test timer 2
 }
 
-void checkTimer(const DateTime& now, sTimer timerInfo)
+void checkTimer(int timer, const DateTime& now)
 {
-  int maskDOW = 0x01 << now.dayOfTheWeek();
-  if(timerInfo.enabled & (maskDOW | 0x80) ) {  // specific day, or next day
-    // check start
-    if(now.hour() == timerInfo.start.hour && now.minute() == timerInfo.start.min) {
+  sTimer Info;
+  NVstore.getTimerInfo(timer, Info);
+  int DOW = now.dayOfTheWeek();
+  int timeNow = now.hour() * 60 + now.minute();
+  int timeStart = Info.start.hour * 60 + Info.start.min;
+  int timeStop = Info.stop.hour * 60 + Info.stop.min;
+
+  // ensure DOW tracks expected start day should timer straddle midnight
+  if(timeStop < timeStart) {   // true if stop is next morning
+    if(timeNow <= timeStop) {  // current time has passed midnight - enable flag is based upon prior day
+      DOW--;
+      ROLLLOWERLIMIT(DOW, 0, 6);   // fixup for saturday night!
+    }
+  }
+  // DOW of week is now correct for the day this timer started
+  int maskDOW = 0x01 << DOW;
+
+  if(Info.enabled & (maskDOW | 0x80) ) {  // specific day of week, or next day
+    
+    if(timeNow == timeStart && now.second() < 3) {  // check start, within 2 seconds of the minute rollover
       requestOn();
     }
-    // check stop
-    if(now.hour() == timerInfo.stop.hour && now.minute() == timerInfo.stop.min) {
+    
+    if(timeNow == timeStop) {            // check stop
       requestOff();
-      if(!timerInfo.repeat) {            // cancel timer if non repeating
-        if(timerInfo.enabled & 0x80)     // next day start flag?
-          timerInfo.enabled = 0;         // outright cancel
-        else
-          timerInfo.enabled &= ~maskDOW; // otherwise clear particular day
-        NVstore.setTimerInfo(0, timerInfo);
+      if(!Info.repeat) {            // cancel timer if non repeating
+        if(Info.enabled & 0x80)     // next day start flag set?
+          Info.enabled = 0;         // outright cancel
+        else {
+          Info.enabled &= ~maskDOW; // otherwise clear specific day
+        }
+        NVstore.setTimerInfo(timer, Info);
         NVstore.save();
       }
     }
diff --git a/Arduino/BTCDieselHeater/Screen.cpp b/Arduino/BTCDieselHeater/Screen.cpp
index 3ae17da..572b4fc 100644
--- a/Arduino/BTCDieselHeater/Screen.cpp
+++ b/Arduino/BTCDieselHeater/Screen.cpp
@@ -29,6 +29,11 @@ CScreen::show()
 {
 }
 
+void 
+CScreen::onSelect()
+{
+}
+
 
 void 
 CScreen::_printMenuText(int x, int y, const char* str, bool selected, eJUSTIFY justify, int border, int radius)
diff --git a/Arduino/BTCDieselHeater/Screen.h b/Arduino/BTCDieselHeater/Screen.h
index 053a280..acf8e50 100644
--- a/Arduino/BTCDieselHeater/Screen.h
+++ b/Arduino/BTCDieselHeater/Screen.h
@@ -48,6 +48,7 @@ protected:
 public:
   CScreen(C128x64_OLED& disp, CScreenManager& mgr); 
   virtual ~CScreen(); 
+  virtual void onSelect();
   virtual bool animate();
   virtual void show();
   virtual void keyHandler(uint8_t event) {};
diff --git a/Arduino/BTCDieselHeater/Screen7.cpp b/Arduino/BTCDieselHeater/Screen7.cpp
index 76cf3bc..e26c17b 100644
--- a/Arduino/BTCDieselHeater/Screen7.cpp
+++ b/Arduino/BTCDieselHeater/Screen7.cpp
@@ -42,9 +42,13 @@ CScreen7::CScreen7(C128x64_OLED& display, CScreenManager& mgr, int instance) : C
   _rowSel = 0;
   _colSel = 0;
   _instance = instance;
-  NVstore.getTimerInfo(_instance, _timer);
 }
 
+void 
+CScreen7::onSelect()
+{
+  NVstore.getTimerInfo(_instance, _timer);
+}
 
 void 
 CScreen7::show()
diff --git a/Arduino/BTCDieselHeater/Screen7.h b/Arduino/BTCDieselHeater/Screen7.h
index fa392c3..d07f2bb 100644
--- a/Arduino/BTCDieselHeater/Screen7.h
+++ b/Arduino/BTCDieselHeater/Screen7.h
@@ -37,6 +37,7 @@ class CScreen7 : public CScreenHeader {
 
 public:
   CScreen7(C128x64_OLED& display, CScreenManager& mgr, int instance);
+  void onSelect();
   void show();
   void keyHandler(uint8_t event);
 };
diff --git a/Arduino/BTCDieselHeater/ScreenManager.cpp b/Arduino/BTCDieselHeater/ScreenManager.cpp
index 14c15aa..1739bc1 100644
--- a/Arduino/BTCDieselHeater/ScreenManager.cpp
+++ b/Arduino/BTCDieselHeater/ScreenManager.cpp
@@ -193,6 +193,9 @@ CScreenManager::refresh()
 void 
 CScreenManager::_switchScreen()
 {
+	if(_currentScreen >= 0)
+		_Screens[_currentScreen]->onSelect();
+		
   reqUpdate();
 }