diff --git a/app/tools/ConfigManager.js b/app/tools/ConfigManager.js
index ed4575b..98d5f76 100644
--- a/app/tools/ConfigManager.js
+++ b/app/tools/ConfigManager.js
@@ -1,4 +1,4 @@
-'use strict'
+	 'use strict'
 /*
   Open Rowing Monitor, https://github.com/laberning/openrowingmonitor
 
@@ -6,6 +6,7 @@
 */
 import defaultConfig from '../../config/default.config.js'
 import { deepMerge } from './Helper.js'
+import log from 'loglevel'
 
 async function getConfig () {
   let customConfig
@@ -16,6 +17,202 @@ async function getConfig () {
   return customConfig !== undefined ? deepMerge(defaultConfig, customConfig.default) : defaultConfig
 }
 
+function checkConfig (configToCheck) {
+  checkRangeValue(configToCheck.loglevel.default, 'loglevel.default',['trace', 'debug', 'info', 'warn', 'error', 'silent'], true, 'error')
+  checkRangeValue(configToCheck.loglevel.RowingEngine, 'loglevel.RowingEngine', ['trace', 'debug', 'info', 'warn', 'error', 'silent'], true, 'error')
+  checkIntegerValue(configToCheck.gpioPin, 'gpioPin', 1, 27, false, false, null)
+  checkIntegerValue(configToCheck.gpioPriority, 'gpioPriority', -7, 0, true, true, 0)
+  checkIntegerValue(configToCheck.gpioMinimumPulseLength, 'gpioMinimumPulseLength', 1, 100000, false, true, 0)
+  checkIntegerValue(configToCheck.gpioPollingInterval, 'gpioPollingInterval', 1, 10, false, true, 10)
+  checkRangeValue(configToCheck.gpioPollingInterval, 'gpioPollingInterval', [1, 2, 5, 10], true, 10)
+  checkRangeValue(configToCheck.gpioTriggeredFlank, 'gpioTriggeredFlank', ['Up', 'Down', 'Both'], false, null)
+  checkIntegerValue(configToCheck.appPriority, 'appPriority', configToCheck.gpioPriority, 0, true, true, 0)
+  checkIntegerValue(configToCheck.webUpdateInterval, 'webUpdateInterval', 80, 1000, false, true, 1000)
+  checkBinaryValue(configToCheck.heartrateMonitorBLE, 'heartrateMonitorBLE', true, true)
+  checkBinaryValue(configToCheck.heartrateMonitorANT, 'heartrateMonitorANT', true, false)
+  checkRangeValue(configToCheck.bluetoothMode, 'bluetoothMode', ['off', 'PM5', 'FTMS', 'FTMSBIKE', 'CPS', 'CSC'], true, 'FTMS')
+  checkIntegerValue(configToCheck.peripheralUpdateInterval, 'peripheralUpdateInterval', 80, 1000, false, true, 1000)
+  checkIntegerValue(configToCheck.numOfPhasesForAveragingScreenData, 'numOfPhasesForAveragingScreenData', 2, null, false, true, 4)
+  checkBinaryValue(configToCheck.createRowingDataFiles, 'createRowingDataFiles', true, true)
+  checkBinaryValue(configToCheck.createRawDataFiles, 'createRawDataFiles', true, true)
+  checkBinaryValue(configToCheck.gzipRawDataFiles, 'gzipRawDataFiles', true, false)
+  checkBinaryValue(configToCheck.createTcxFiles, 'createTcxFiles', true, true)
+  checkBinaryValue(configToCheck.gzipTcxFiles, 'gzipTcxFiles', true, false)
+  if (configToCheck.createRowingDataFiles || configToCheck.createRawDataFiles || configToCheck.createTcxFiles) {
+  }
+  checkFloatValue(configToCheck.userSettings.restingHR, 'userSettings.restingHR', 30, 220, false, true, 40)
+  checkFloatValue(configToCheck.userSettings.maxHR, 'userSettings.maxHR', configToCheck.userSettings.restingHR, 220, false, true, 220)
+  if (configToCheck.createTcxFiles) {
+    checkFloatValue(configToCheck.userSettings.minPower, 'userSettings.minPower', 1, 500, false, true, 50)
+    checkFloatValue(configToCheck.userSettings.maxPower, 'userSettings.maxPower', 100, 6000, false, true, 500)
+    checkFloatValue(configToCheck.userSettings.distanceCorrectionFactor, 'userSettings.distanceCorrectionFactor', 0, 50, false, true, 5)
+    checkFloatValue(configToCheck.userSettings.weight, 'userSettings.weight', 25, 500, false, true, 80)
+    checkRangeValue(configToCheck.userSettings.sex, 'userSettings.sex', ['male', 'female'], true, 'male')
+    checkBinaryValue(configToCheck.userSettings.highlyTrained, 'userSettings.highlyTrained', true, false)
+  }
+  checkIntegerValue(configToCheck.rowerSettings.numOfImpulsesPerRevolution, 'rowerSettings.numOfImpulsesPerRevolution', 1, null, false, false, null)
+  checkIntegerValue(configToCheck.rowerSettings.flankLength, 'rowerSettings.flankLength', 3, null, false, false, null)
+  checkFloatValue(configToCheck.rowerSettings.sprocketRadius, 'rowerSettings.sprocketRadius', 0, 20, false, true, 3)
+  checkFloatValue(configToCheck.rowerSettings.minimumTimeBetweenImpulses, 'rowerSettings.minimumTimeBetweenImpulses', 0, 3, false, false, null)
+  checkFloatValue(configToCheck.rowerSettings.maximumTimeBetweenImpulses, 'rowerSettings.maximumTimeBetweenImpulses', configToCheck.rowerSettings.minimumTimeBetweenImpulses, 3, false, false, null)
+  checkFloatValue(configToCheck.rowerSettings.smoothing, 'rowerSettings.smoothing', 1, 1000000, false, true, 1)
+  checkFloatValue(configToCheck.rowerSettings.dragFactor, 'rowerSettings.dragFactor', 1, 1000000, false, false, null)
+  checkBinaryValue(configToCheck.rowerSettings.autoAdjustDragFactor, 'rowerSettings.autoAdjustDragFactor', true, false)
+  checkIntegerValue(configToCheck.rowerSettings.dragFactorSmoothing, 'rowerSettings.dragFactorSmoothing', 1, 1000, false, true, 1)
+  if (configToCheck.rowerSettings.autoAdjustDragFactor) {
+    checkFloatValue(configToCheck.rowerSettings.minimumDragQuality, 'rowerSettings.minimumDragQuality', 0, 1, true, true, 0)
+  }
+  checkFloatValue(configToCheck.rowerSettings.flywheelInertia, 'rowerSettings.flywheelInertia', 0, 2, false, false, null)
+  checkFloatValue(configToCheck.rowerSettings.minumumForceBeforeStroke, 'rowerSettings.minumumForceBeforeStroke', 0, 500, true, true, 0)
+  checkFloatValue(configToCheck.rowerSettings.minumumRecoverySlope, 'rowerSettings.minumumRecoverySlope', 0, 2, true, true, 0)
+  checkFloatValue(configToCheck.rowerSettings.minimumStrokeQuality, 'rowerSettings.minimumStrokeQuality', 0, 1, true, true, 0)
+  checkBinaryValue(configToCheck.rowerSettings.autoAdjustRecoverySlope, 'rowerSettings.autoAdjustRecoverySlope', true, false)
+  if (!configToCheck.rowerSettings.autoAdjustDragFactor && configToCheck.rowerSettings.autoAdjustRecoverySlope) {
+    log.error('Configuration Error: rowerSettings.autoAdjustRecoverySlope can not be true when configToCheck.rowerSettings.autoAdjustDragFactor is false, ignoring request')
+  }
+  if (configToCheck.rowerSettings.autoAdjustDragFactor && configToCheck.rowerSettings.autoAdjustRecoverySlope) {
+    checkFloatValue(configToCheck.rowerSettings.autoAdjustRecoverySlopeMargin, 'autoAdjustRecoverySlopeMargin', 0, 1, false, true, 1)
+  }
+  checkFloatValue(configToCheck.rowerSettings.minimumDriveTime, 'minimumDriveTime', 0, 6, false, true, 0.001)
+  checkFloatValue(configToCheck.rowerSettings.minimumRecoveryTime, 'minimumRecoveryTime', 0, 6, false, true, 0.001)
+  checkFloatValue(configToCheck.rowerSettings.maximumStrokeTimeBeforePause, 'maximumStrokeTimeBeforePause', 3, 60, false, true, 6)
+  checkFloatValue(configToCheck.rowerSettings.magicConstant, 'magicConstant', 0, 28, false, true, 2.8)
+}
+
+function checkIntegerValue (parameter, parameterName, minimumValue, maximumvalue, allowZero, allowRepair, defaultValue) {
+  let errors = 0
+  switch (true) {
+    case (parameter == undefined):
+    log.error(`Configuration Error: ${parameterName} isn't defined`)
+    errors++
+    break
+  case (!Number.isInteger(parameter)):
+    log.error(`Configuration Error: ${parameterName} should be an integer value, encountered ${parameter}`)
+    errors++
+    break
+  case (minimumValue != null && parameter < minimumValue):
+    log.error(`Configuration Error: ${parameterName} should be at least ${minimumValue}, encountered ${parameter}`)
+    errors++
+    break
+  case (maximumvalue != null && parameter > maximumvalue):
+    log.error(`Configuration Error: ${parameterName} can't be above ${maximumvalue}, encountered ${parameter}`)
+    errors++
+    break
+  case (!allowZero && parameter == 0):
+    log.error(`Configuration Error: ${parameterName} can't be zero`)
+    errors++
+    break
+  default:
+    // No error detected :)
+  }
+  if (errors > 0) {
+    // Errors were made
+    if (allowRepair) {
+      log.error(`   resolved by setting ${parameterName} to ${defaultValue}`)
+      // ToDo: fix this by making the function call a call by reference!!!
+      parameter = defaultValue
+    } else {
+      log.error(`As ${parameterName} is a fatal parameter, I'm exiting`)
+      process.exit(9)
+    }
+  }
+}
+
+function checkFloatValue (parameter, parameterName, minimumValue, maximumvalue, allowZero, allowRepair, defaultValue) {
+  let errors = 0
+  switch (true) {
+    case (parameter == undefined):
+    log.error(`Configuration Error: ${parameterName} isn't defined`)
+    errors++
+    break
+  case (!typeof(parameter)==="number"):
+    log.error(`Configuration Error: ${parameterName} should be a numerical value, encountered ${parameter}`)
+    errors++
+    break
+  case (minimumValue != null && parameter < minimumValue):
+    log.error(`Configuration Error: ${parameterName} should be at least ${minimumValue}, encountered ${parameter}`)
+    errors++
+    break
+  case (maximumvalue != null && parameter > maximumvalue):
+    log.error(`Configuration Error: ${parameterName} can't be above ${maximumvalue}, encountered ${parameter}`)
+    errors++
+    break
+  case (!allowZero && parameter == 0):
+    log.error(`Configuration Error: ${parameterName} can't be zero`)
+    errors++
+    break
+  default:
+    // No error detected :)
+  }
+  if (errors > 0) {
+    // Errors were made
+    if (allowRepair) {
+      log.error(`   resolved by setting ${parameterName} to ${defaultValue}`)
+      // ToDo: fix this by making the function call a call by reference!!!
+      parameter = defaultValue
+    } else {
+      log.error(`As ${parameterName} is a fatal parameter, I'm exiting`)
+      process.exit(9)
+    }
+  }
+}
+
+function checkBinaryValue (parameter, parameterName, allowRepair, defaultValue) {
+  let errors = 0
+  switch (true) {
+    case (parameter == undefined):
+    log.error(`Configuration Error: ${parameterName} isn't defined`)
+    errors++
+    break
+  case (!(parameter === true || parameter === false)):
+    log.error(`Configuration Error: ${parameterName} should be either false or true, encountered ${parameter}`)
+    errors++
+    break
+  default:
+    // No error detected :)
+  }
+  if (errors > 0) {
+    // Errors were made
+    if (allowRepair) {
+      log.error(`   resolved by setting ${parameterName} to ${defaultValue}`)
+      // ToDo: fix this by making the function call a call by reference!!!
+      parameter = defaultValue
+    } else {
+      log.error(`As ${parameterName} is a fatal parameter, I'm exiting`)
+      process.exit(9)
+    }
+  }
+}
+
+function checkRangeValue (parameter, parameterName, range, allowRepair, defaultValue) {
+  let errors = 0
+  switch (true) {
+    case (parameter == undefined):
+    log.error(`Configuration Error: ${parameterName} isn't defined`)
+    errors++
+    break
+  case (!range.includes(parameter)):
+    log.error(`Configuration Error: ${parameterName} should be come from ${range}, encountered ${parameter}`)
+    errors++
+    break
+  default:
+    // No error detected :)
+  }
+  if (errors > 0) {
+    // Errors were made
+    if (allowRepair) {
+      log.error(`   resolved by setting ${parameterName} to ${defaultValue}`)
+      // ToDo: fix this by making the function call a call by reference!!!
+      parameter = defaultValue
+    } else {
+      log.error(`As ${parameterName} is a fatal parameter, I'm exiting`)
+      process.exit(9)
+    }
+  }
+}
+
 const config = await getConfig()
 
+checkConfig(config)
+
 export default config