Hello again. Following a protocol I saw online I have the ES8 Mute button set to be global via system settings so that it is always performing  the same function across all patches. The function I have it programmed to do is turn on the tuner in the H9 . It looks like it want to work except that even though the H9 shows "Tuner" on the display it doesn't respond. And it isn't because the ES8 is muted. I can hear the guitar. But I shouldn't hear the guitar if the H9 tunes was active. That should mute the H9. Any idea why the tuner isn't working in this case ? Thank you.

You can set H9's tuner to be either Bypass or Mute. The manual tells how you can set that.