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Sunsynk F22: Emergency Stop Fault

Updated June 2026 · Reviewed for technical accuracy · ~2 min read

F22 (shown internally as "Tz_EmergStop") is an emergency-stop or hardware protection fault. Your Sunsynk has tripped a protective shutdown. Sometimes an external emergency-stop or grid-control signal causes it; more often it points to an internal protection that is best checked by your installer.

What can trigger F22

  • An external emergency-stop or DRM signal. Some systems wire an emergency-stop button or a grid demand-response device to the inverter. If it is engaged, the Sunsynk stops.
  • A wiring issue on that control port, such as a loose or incorrect connection.
  • An internal hardware protection tripping, which needs professional diagnosis.

What to do, safely

  1. Check for an emergency-stop device. If your system has an emergency-stop button or DRM connection, make sure it is not pressed or engaged, and release it if so.
  2. Do one safe power cycle. AC breaker off, then the DC isolator, wait five minutes, restart both.
  3. If F22 returns, stop. Don't keep resetting a protection fault. Contact your installer with the code and model.
When to bring in a professional F22 is a protection trip. If there is no engaged emergency-stop device and it returns after a restart, it points to an internal fault. That needs your installer or Sunsynk support, not repeated resets.

Related Sunsynk codes

F41, Parallel system stop F63, Arc fault F08, GFDI relay failure

FAQ

I don't have an emergency-stop button. Why F22?

Then F22 most likely reflects an internal protection trip rather than an external signal. A single restart can clear a one-time glitch, but a returning F22 should be inspected by your installer.

Is it safe to keep restarting it?

No. Repeatedly clearing a protection fault defeats its purpose. Restart once; if it comes back, get it checked.

Sources

  • Sunsynk Hybrid Inverter User Manual (F22 = Tz_EmergStop emergency-stop fault; contact installer for help).
  • Sunsynk fault-code references and installer documentation.
⚠️ Safety disclaimer. Solar inverters carry lethal DC and AC voltage even when "off". This guide covers a control-device check and a single safe power cycle only. Internal protection faults must be diagnosed by a licensed installer or electrician.