diff --git a/fhem/FHEM/00_ZWDongle.pm b/fhem/FHEM/00_ZWDongle.pm
index 6bf772fc9..088930670 100755
--- a/fhem/FHEM/00_ZWDongle.pm
+++ b/fhem/FHEM/00_ZWDongle.pm
@@ -405,6 +405,7 @@ ZWDongle_shiftSendStack($$$$)
     $hash->{WaitForAck}=0;
     $hash->{SendRetries}=0;
     $hash->{MaxSendRetries}=3;
+    delete($hash->{GotCAN});
   }
 }
 
@@ -450,6 +451,7 @@ ZWDongle_ProcessSendStack($)
   DevIo_SimpleWrite($hash, $msg, 1);
   $hash->{WaitForAck} = 1;
   $hash->{SendTime} = $ts;
+  delete($hash->{GotCAN});
 
   InternalTimer($ts+1, "ZWDongle_ProcessSendStack", $hash, 0);
 }
@@ -500,6 +502,7 @@ ZWDongle_Read($@)
       Log3 $name, 4, "ZWDongle_Read $name: CAN received";
       $hash->{MaxSendRetries}++ if($hash->{MaxSendRetries}<7);
       $data = substr($data, 2);
+      $hash->{GotCAN} = 1;
       if(!$init_done) { # InternalTimer wont work
         $hash->{WaitForAck} = 0;
         $hash->{SendRetries}++;
@@ -539,7 +542,7 @@ ZWDongle_Read($@)
       next;
     }
     $hash->{nrNAck} = 0;
-    Log3 $name, 4, "ZWDongle_Read $name: sending ACK, processing $msg";
+    Log3 $name, 4, "ZWDongle_Read $name: rcvd $msg, sending ACK";
     DevIo_SimpleWrite($hash, "06", 1);          # Send ACK
     ZWDongle_shiftSendStack($hash, 1, 5, "device ack reveived")
         if($msg =~ m/^0013/);
@@ -634,8 +637,8 @@ ZWDongle_Parse($$$)
   $hash->{"${name}_TIME"} = TimeNow();
   $hash->{RAWMSG} = $rmsg;
 
-  $hash->{SendTime} = 0       # Retry sending after a "real" msg from the dongle
-        if($hash->{WaitForAck} && $rmsg !~ m/^(0113|0013)/); 
+  $hash->{SendTime}--       # Retry sending after a "real" msg from the dongle
+        if($hash->{GotCAN} && $rmsg !~ m/^(0113|0013)/); 
 
   my %addvals = (RAWMSG => $rmsg);
 
diff --git a/fhem/FHEM/10_ZWave.pm b/fhem/FHEM/10_ZWave.pm
index 14e029875..006e66e3d 100755
--- a/fhem/FHEM/10_ZWave.pm
+++ b/fhem/FHEM/10_ZWave.pm
@@ -3549,7 +3549,7 @@ ZWave_isWakeUp($)
 # type is: set / sentset, get / sentget / sentackget
 # sentset will be discarded after ack, sentget needs ack (->sentackget) then msg
 # next discards either state.
-# acktpye: next, ack or msg
+# acktpye: retry, next, ack or msg
 sub
 ZWave_processSendStack($$;$)
 {
@@ -3557,13 +3557,20 @@ ZWave_processSendStack($$;$)
   my $ss = $hash->{SendStack};
   return if(!$ss);
 
+  if($ackType eq "retry") {
+    $ss->[0] =~ m/^(.*)(set|get):(.*)$/;
+    $ss->[0] = "$2:$3";
+    return;
+  }
+
   if($ss->[0] =~ m/^sent(.*?):(.*)$/) {
-    if($1 eq "get" && $ackType eq "ack") {
-      $ss->[0] = "sentackget:$2";
+    my ($stype,$smsg) = ($1,$2);
+    if($stype =~ m/get/ && $ackType eq "ack") { # accept double-ACK
+      $ss->[0] = "sentackget:$smsg";
       return;
 
-    } elsif($1 eq "ackget" && $ackType eq "msg") {# compare answer class for get
-      my $cs = substr($2, 6, 2);
+    } elsif($stype eq "ackget" && $ackType eq "msg") {# compare answer class
+      my $cs = substr($smsg, 6, 2);
       my $cg = substr($omsg, 2, 2);
       return if($cs ne $cg);
     }
@@ -3654,7 +3661,7 @@ ZWave_Parse($$@)
           readingsSingleUpdate($hash, "SEND_DATA", "failed:$arg", 1);
           $arg = "transmit queue overflow" if($arg == 0);
           Log3 $ioName, 2, "ERROR: cannot SEND_DATA to $hash->{NAME}: $arg";
-          ZWave_processSendStack($hash, "next");
+          ZWave_processSendStack($hash, "retry");
 
         } else {
           Log3 $ioName, 2, "ERROR: cannot SEND_DATA: $arg (unknown device)";
@@ -3758,7 +3765,7 @@ ZWave_Parse($$@)
       }
       return "";
 
-    } else {
+    } else { # Wait for the retry timer to remove this cmd from the stack.
       Log3 $ioName, 2, "$ioName transmit $lmsg for $callbackid";
       return "" if(!$hash);
       readingsSingleUpdate($hash, "state", "TRANSMIT_$lmsg", 1);