diff --git a/solarpump/solarpump.ino b/solarpump/solarpump.ino
index 67cc7e9f346c2b8a2269c4c8942fb4524837507f..56c828c8f75acb3dbf9613100d03be7c20f15b12 100644
--- a/solarpump/solarpump.ino
+++ b/solarpump/solarpump.ino
@@ -50,7 +50,7 @@ void controlPump(uint8_t pumpPin, float tempUp, float tempDown) {
 /*
  * prints a float where the decimals specify the numbers of digit, which are printed,
  * after the decimal point and
- *  rightPad specifies the total length printed, where empty spots are filled with spaces
+ * rightPad specifies the total length printed, where empty spots are filled with spaces
  */
 void printFloat(float f, uint8_t decimals, uint8_t rightPad) {
 	String s = String(f, decimals);
@@ -145,7 +145,7 @@ void displayLight(bool turnOn) {
 		lcd.backlight();
 		prevMillis = millis();
 		curState = true;
-	// turn off after lightMillis ms
+	// turn off after lightMillis (30 000 ms)
 	} else if (curState && millis() - prevMillis > lightMillis) {
 		lcd.noBacklight();
 		curState = false;
diff --git a/solarpump/soundFiles.h b/solarpump/soundFiles.h
index 8a31b014c986384d11fb269743591933fda4465a..9fc1dbaef4e340074293e238ef7ab955338e4732 100644
--- a/solarpump/soundFiles.h
+++ b/solarpump/soundFiles.h
@@ -1,8 +1,10 @@
 #ifndef SOUNDFILES_H
 #define SOUNDFILES_H
 
-// index for the sound files for mp3 module TDB380
-// the files are .mp3 instead of .wav
+/* 
+ * index for the sound files for mp3 module TDB380
+ * the files are .mp3 instead of .wav
+ */ 
 #define SOUND_NULL            33  // A033.wav
 #define SOUND_EIN             1   // A001.wav
 #define SOUND_EINS            44  // A044.wav
diff --git a/solarpump/temperature.ino b/solarpump/temperature.ino
index a4e9243ddb85ef7dac9fc2f5e915073082545960..eb51c0223e335dbb72458d32b1ae6f9705a8dafc 100644
--- a/solarpump/temperature.ino
+++ b/solarpump/temperature.ino
@@ -4,25 +4,39 @@
 #include <DHT.h>
 
 /* No new valid temperature for < 60 seconds? I sleep.
- * No new valid temperature for > 60 seconds? REAL PROBLEM! */
+ * No new valid temperature for > 60 seconds? REAL PROBLEM! 
+ */
 const uint32_t ERRORTIME =  10000;
 // Update the temperature only every second
 const uint32_t TEMPUPDATETIME = 1000;
 
-// UP temperature for solar system 1
+/* 
+ * UP temperature for solar system 1
+ * 1. update only after a second (TEMPUPDATETIME) otherwise return UNCHANGED
+ * 2. get temperature from temperatur sensor check for errors
+ * 3. return ERROR if error occured first time
+ * 4. if error occurred longer than 10 s (ERRORTIME) return LONG_TIME_ERROR
+ * 5. update temperatur, time variables and return SUCCESS
+ * function below work the same, except that they use another
+ * temperature sensor library
+ */
 static OneWire oneWireT1up(T1UP);
 static DallasTemperature dallasTemps(&oneWireT1up);
 UPDATESTATE t1up(float* temp) {
 	static uint32_t prevMillis = 0;
 	static uint32_t errorStartMillis = 0;
 	uint32_t curMillis = millis();
+  // only update once a second
 	if (curMillis - prevMillis < TEMPUPDATETIME) {
 		return UNCHANGED;
 	}
+  // get temperature from sensor 
 	dallasTemps.requestTemperatures();
 	float tempC = dallasTemps.getTempCByIndex(0);
+  // check if error occured
 	if (tempC == DEVICE_DISCONNECTED_C) {
 		if (errorStartMillis) {
+      // check if error occurred longer than some seconds (10s)
 			if (curMillis - errorStartMillis > ERRORTIME) {
 				return LONG_TIME_ERROR;
 			}
@@ -32,6 +46,7 @@ UPDATESTATE t1up(float* temp) {
 		return ERROR;
 	}
 
+  // update temperature and time variables
 	*temp = tempC;
 	errorStartMillis = 0;
 	prevMillis = curMillis;