diff --git a/tecs/tecs.c b/tecs/tecs.c
index 71ed28c1..94756901 100644
--- a/tecs/tecs.c
+++ b/tecs/tecs.c
@@ -586,13 +586,15 @@ int PeriodicTask(void) {
         str_copy(cryo.device, buf1+1);
         cryo.manual=1;
       } else {
-        str_copy(cryo.device, buf1);
+        if (cryo.code!=0) str_copy(cryo.device, buf1);
+        cryo.manual=0;
       }
       if (buf2[0]=='*') {
         str_copy(samp.device, buf2+1);
         samp.manual=1;
       } else {
-        str_copy(samp.device, buf2);
+        if (samp.code!=0) str_copy(samp.device, buf2);
+        samp.manual=0;
       }
       concatDevice();
       if (cryo.manual || cryo.code!=0) { cryo.dirty=1; }
@@ -860,8 +862,8 @@ int ExecuteRequest(void) {
     t=strchr(device, '/');
     if (t==NULL) {
       if (0==strcmp(device, "0") || 0==strcasecmp(device, "auto")) {
-        cryo.manual=0; cryo.dirty=1;
-        samp.manual=0; samp.dirty=1;
+        cryo.manual=0; cryo.dirty=1; cryo.device[0]='\0';
+        samp.manual=0; samp.dirty=1; samp.device[0]='\0';
       } else {
         str_copy(cryo.device, device);
         str_copy(samp.device, device);