Emergency Quick Reference¶
Print this page. Laminate it. Keep one copy at the generator panel and one at the operator location. Everything you need to know about the EPO and HOA switches in 60 seconds.
For the full operator guide see Hardware Switches.
If something's wrong RIGHT NOW¶
| Situation | Do this |
|---|---|
| Generator is running and you need it OFF immediately, and you're at the generator | Press the red EPO mushroom button. Generator stops physically. Twist clockwise to release when safe. |
| Generator is running and you need it OFF, and you're at the operator location | Web UI → Generator page → Emergency Stop (big red STOP button, top-right). |
| You can't reach the web UI | Press the EPO at the generator. Hardware always works, even if every Pi is offline. |
| EPO is engaged and you don't know why | Look at the generator. If someone is servicing it, leave the EPO engaged. Only release if you know nobody is at the generator. |
The EPO mushroom button (at the generator)¶
A red push-button on the generator panel. Press = lock the generator off. Twist clockwise = unlock.
- The button physically opens the start-relay wire. The generator cannot start while it's pressed — not by automation, not by manual web start, not by anything.
- When the EPO is engaged: the web UI shows a pulsing red banner, the Start Generator button is greyed out, and the GenSlave LCD reads
EPO SAFETY ON. - When you release the EPO: automation resumes within ~60 seconds (the heartbeat cycle). If Victron is still asking for the generator, GenMaster will start it on the next tick. There is no "rearm" step.
- You must twist the head clockwise to release. Pulling won't work — it's designed that way.
If the EPO won't release: it may be stuck in the cocked position. Press it once more, then twist clockwise firmly. If still stuck, the contact block has failed — call for service. The generator will remain unable to start (this is the safe failure mode).
The HOA selector (at the operator location)¶
A 3-position rotary knob: Quiet / Auto / Run (counter-clockwise to clockwise).
| Position | What it does |
|---|---|
| Quiet (CCW) | Suppresses automatic runs (Victron, scheduled, exercise). Manual web starts still work. Use overnight or when you want silence. |
| Auto (center) | Normal operation. Automation runs as configured. Default position. |
| Run (CW) | Operator is explicitly asking for the generator. GenMaster starts it and keeps it running until you turn the selector back to Auto. |
The HOA is NOT a safety device. It's an operator-side mode selector. If you need to physically guarantee the generator can't start, use the EPO at the generator, not the HOA.
If the HOA cable is cut or both contacts read closed at the same time: the system reports a fault on the web UI and treats the selector as Auto. Automation continues. Check the wiring; fault clears when the condition is resolved.
Quiet override (one-off bypass without leaving Quiet)¶
If the selector is in Quiet but you need automation to fire just this once (e.g. Victron wants 15 minutes to top up the batteries):
- Open the GenMaster web UI → Generator page
- On the blue Quiet banner, click Override
- Pick a duration in minutes
- Automation fires normally until the timer expires (or until you turn the selector out of Quiet, which auto-clears the override)
Click Cancel Override on the banner to end it early.
Combined states¶
When both the EPO and the HOA are active:
- The EPO always wins — generator cannot start.
- The HOA banner changes its wording to acknowledge the EPO (e.g. "Quiet Mode — EPO Active", "Run Mode — Held by EPO").
- In the Quiet + EPO case, the Override button is hidden — you can't override Quiet while the EPO is engaged because there's nothing to override.
When the EPO releases:
- If HOA is in Run: GenMaster starts the generator on the next heartbeat.
- If HOA is in Quiet (no override): automation stays suppressed; manual starts available.
- If HOA is in Auto: automation resumes per Victron / schedule / exercise.
When in doubt, EPO¶
If you're not sure what to do, engage the EPO at the generator. The system always fails safe from that state. You can release it once you know what's going on.
Contact info — fill in for your install¶
| Role | Name | Phone | Notes |
|---|---|---|---|
| System owner | ___ | ___ | Knows the install end-to-end |
| Generator service | ___ | ___ | Generator manufacturer's service line |
| Electrician | ___ | ___ | Wired the panel — for hardware issues |
| Solar/Inverter installer | ___ | ___ | If Victron behavior is unexpected |
Web UI: ___________________________________________ (fill in your Cloudflare tunnel hostname or Tailscale name)
SSH to GenMaster (last-resort access): ___________________________________________