diff --git a/README.md b/README.md
index 122a79f..6ba3198 100644
--- a/README.md
+++ b/README.md
@@ -201,10 +201,15 @@ Depending on your HP model, SG3 might be configurable in "ECO mode", "Normal mod
 Note: Smart Grid needs to be switched ON in the heatpump configuration menu, otherwise SG1 and SG2 contacts are not evaluated.
 
 ## Step 5 (optional) - Pulse Meter feature
-ESPaltherma can communicate how much energy the HP should consume via a pulse meter. For this, uncomment and confugre `PIN_PULSE`, `PULSES_PER_kWh` and `PULSE_DURATION_MS` in `src/setup.c`. Send energy amount in Watt to MQTT channel `espaltherma/pulse/set`. Current Watt setting is available in `espaltherma/pulse/state`.  
+ESPaltherma can communicate how much energy the HP should consume via a pulse meter. For this, uncomment and confugre `PIN_PULSE`, `PULSES_PER_kWh` and `PULSE_DURATION_MS` in `src/setup.h`. Send energy amount in Watt to MQTT channel `espaltherma/pulse/set`. Current Watt setting is available in `espaltherma/pulse/state`.
 
 *TODO more close description what it is to do*
 
+Note the limits to reporded Watt. Both limits depend on
+* `PULSES_PER_kWh` (default is 1000)
+* `PULSE_DURATION_MS` (default is 75)
+For these defaults, the minimum reported power is 60 and the maximum is 21 kWh. If you need to represent more power, try reducing `PULSE_DURATION_MS`. If this is not sufficient, adapt `PULSES_PER_kWh` but keep it in sync with the HP setting.
+
 # Troubleshooting
 
 ## Specific issues with M5
diff --git a/include/mqtt.h b/include/mqtt.h
index 1e29238..8fdc78b 100644
--- a/include/mqtt.h
+++ b/include/mqtt.h
@@ -258,18 +258,24 @@ void callbackPulse(byte *payload, unsigned int length)
   String ss((char*)payload);
   long target_watt = ss.toInt();
 
-  // TODO check for maximum supported watt setting (smaller duration between pulse than pulse lenght)
-
   // also converts from kWh to Wh
-  float WH_PER_PULSE = 1.0 / PULSES_PER_kWh * 1000;
+  float WH_PER_PULSE = (1.0 / PULSES_PER_kWh) * 1000;
 
-  ms_until_pulse = (3600.0 / target_watt * WH_PER_PULSE * 1000) - PULSE_DURATION_MS;
+  ms_until_pulse = ((3600.0 / target_watt) * WH_PER_PULSE * 1000) - PULSE_DURATION_MS;
   if ((ms_until_pulse + PULSE_DURATION_MS) > 60 * 1000) {
     // cap the maximum pulse length to 1 minute
     // a change of the pulse is only applied, after the current pulse is finished. Thus if the pulse rate is very low,
     // it will take a long time to adjust the rate
     ms_until_pulse = 60 * 1000;
-    Serial.printf("Capping pulse to %d Watt to ensure pulse rate is <= 60 sec\n", (int) WH_PER_PULSE * 60);
+    target_watt = (long) WH_PER_PULSE * 60;
+    Serial.printf("Capping pulse to %d Watt to ensure pulse rate is <= 60 sec\n", target_watt);
+  }
+  if (ms_until_pulse < 20) {
+    // ensure a 20 ms gap between two pulses
+    ms_until_pulse = 20;
+    long original_target = target_watt;
+    target_watt = (long) ((1000 * WH_PER_PULSE * 3600) / (ms_until_pulse + PULSE_DURATION_MS));
+    Serial.printf("WARNING pulse frequency to high, capping at %d Watt! Target is %d Watt. Decrease PULSE_DURATION or PULSES_PER_kWh\n", target_watt, original_target);
   }
   if (timerPulseStart == NULL) {
     setupPulseTimer();