Testing an AED means confirming the device’s automatic self-test has passed, not manually triggering a real shock. Every modern AED runs its own internal diagnostic daily or weekly, checking battery voltage, pad connectivity, and internal circuitry, and reports the result through a status indicator.
“Testing” the device, in practice, means reading that result correctly, occasionally triggering a manual self-check where the model supports it, and knowing the difference between that and a training-mode simulation that uses no real patient pads at all.
🚫 Get this right first: You cannot and should not “test” an AED by discharging a real shock — not into the air, not onto an unneeded person, not as a demonstration. Doing so wastes a single-use set of pads, can deliver an unwanted shock to whoever is holding it, and tells you nothing the self-test doesn’t already confirm. Every manufacturer’s manual is explicit about this. The confusion usually comes from conflating three different things: the automatic self-test (passive, constant), a manual diagnostic trigger (available on some models), and training mode (a separate simulation system using trainer-specific equipment, not the real device).
This guide separates those three clearly, walks through how to read and trigger each on the major brands, and covers the specific moments — after a battery swap, after unboxing a new unit, after an actual rescue — when a deliberate test matters most.
The 3 things people mean when they say “test an AED”
| What you’re testing | How it works | Risk if done wrong | Frequency |
|---|---|---|---|
| Automatic self-test | Runs on its own, daily or weekly depending on brand | None, fully passive | Continuous, built into the device |
| Manual diagnostic trigger | User-initiated check via button sequence, available on some models | Low, as long as you don’t attempt to fire a shock | As needed (after maintenance, when troubleshooting) |
| Training mode / simulator | Uses trainer pads and a training cartridge, completely separate from the real device’s shock circuit | None to the device, but never substitute trainer gear for real patient care | During CPR/AED certification courses |
⚠️ Only the first two matter for readiness. The third is for teaching people how to use one. A unit switched into training mode (where that feature exists) will not deliver a real shock even in an actual emergency until switched back.
How the automatic self-test works (and how to read it)
Every modern AED — Philips HeartStart, Zoll AED Plus, Cardiac Science Powerheart, Defibtech Lifeline, Stryker LifePak — runs scheduled self-tests that check three things: battery voltage and capacity, pad connection and circuit continuity, and internal electronics including the capacitor that delivers the shock charge. The device reports the result through its status indicator, a small window or light on the front of the unit.
✅ Pass
Green check, solid or blinking green light, “OK” text — last self-test passed, device is ready.
❌ Fail
Red X, flashing red, hourglass that doesn’t resolve, blank window — last self-test failed, device is out of service until the issue is resolved.
This is the test that matters for day-to-day readiness, and you don’t trigger it — it runs on its own. Your job is making sure someone actually looks at the result. A passed self-test sitting unread in an empty hallway accomplishes nothing.
How to manually trigger a self-check (where available)
Some models let you initiate a diagnostic on demand, useful after replacing a battery or pads, or when you want to confirm a fix actually worked before walking away.
Philips HeartStart (OnSite, FRx, FR3)
Press and hold the blue “i” information button to hear the device speak its current status out loud, including any specific fault code. This doesn’t run a new test on demand so much as report the result of the last one, but it’s the fastest way to get a spoken diagnosis instead of decoding a blinking light.
Zoll AED Plus and AED 3
Pressing the green “On” button initiates the unit’s startup self-check sequence. The unit will run through its internal verification, voice prompts will begin, and the status window will show a green check or red X. Holding the on/off button for about 2 seconds powers the unit back down once you’ve confirmed the result.
Cardiac Science Powerheart (G3, G5)
The Rescue Ready indicator reflects the most recent scheduled self-test. There’s no separate on-demand diagnostic button on most models — the indicator itself is the test result.
Defibtech Lifeline
Pressing any button while the unit is chirping triggers a spoken fault code describing the specific failure, similar to the Philips “i” button approach.
Stryker LifePak (CR2, CR Plus)
Powering the unit on runs through its startup self-check, with the result shown on the indicator window.
Important: None of these manual triggers deliver a shock or require pads to be removed from their sealed packaging. They confirm the device’s internal readiness, nothing more.
What to test after specific events
A few situations call for a deliberate check beyond the routine monthly inspection.
🔋 After replacing a battery
Power the unit on, let the startup self-check run, and confirm the status indicator shows ready before closing the cabinet. Occasionally a unit with a charging-circuit fault will reject even a brand-new battery, which looks identical to “bad battery” from the outside — this check is what catches that before the device goes back into service.
🩹 After replacing pads
Same principle. Connect the new pads, power on, confirm the connection registers without an error. If the unit reports a pad connectivity fault with new, in-date pads installed, the connector or cable itself may be the problem rather than the pads.
📦 After unboxing a brand-new AED
Run the unit’s startup self-check before mounting it in its permanent location. Confirm the status indicator passes, confirm the included battery’s install-by date, and register the device with the manufacturer if that’s part of setup. Don’t wait for the first monthly inspection to discover a unit arrived with a problem.
🚑 After an actual rescue
The device’s self-test isn’t the priority in the immediate aftermath — replacing the used pads and checking the battery are. But once the unit is back in the cabinet with fresh pads installed, run the same post-replacement check to confirm it returns to ready status. Many manufacturers also recommend downloading the event data for their own review process after any real use.
🔧 During annual professional servicing
A trained AED technician can run deeper diagnostics than the device’s own self-test — firmware version verification, internal capacitor health checks, and confirmation against any open manufacturer recalls. For compliance-heavy environments (schools, healthcare facilities, government buildings), an annual technician visit on top of monthly self-checks is a defensible standard.
What testing does not confirm
This trips people up: a passed self-test does not mean every part of the AED program is compliant. The self-test verifies the device’s internal electronics and battery voltage. It does not confirm:
- Whether the battery or pads are within their printed expiration date (a battery can have voltage and still be past its install-by date)
- Whether the rescue kit (scissors, razor, gloves, mask) is complete
- Whether a designated responder’s CPR/AED certification is current
- Whether the cabinet alarm functions, on units where one exists
- Whether the device is registered with local EMS, in states that require it
A green status light answers “is the electronics and current battery functional,” nothing about dates, supplies, or documentation. The full monthly inspection checklist covers all of that together, and is the right tool for the complete monthly walk-through rather than the self-test alone.
💡 Self-test results, pad/battery dates, and cert tracking — all logged in one place automatically.
Training mode: how staff practice without risking the real device
Several AED models, including the Philips HeartStart FRx, support a training mode activated by a physical switch or a separate training cartridge. In this mode, the unit runs through its full voice-prompt sequence and simulated analysis using trainer pads designed for repeated use on a manikin, with no connection to the device’s actual shock-delivery circuit. This is what CPR/AED certification courses use for hands-on practice.
⚠️ Critical safety point: Training mode and the real device must never be confused. A unit left in training mode would not deliver a shock in an actual emergency, and a unit with trainer pads connected has no analyze or shock capability regardless of mode. After any training session, confirm the unit is switched back to operational mode and the real, in-date adult pads are reconnected before returning it to the cabinet.
What never to do when “testing” an AED
- Never attempt to manually fire a shock to see if the device works. This is not how self-tests function, wastes single-use pads, and risks injury to whoever is holding the unit.
- Never apply real pads to a person who isn’t in cardiac arrest to “test” the analysis function. The device is designed to analyze real cardiac rhythms, not to be demonstrated on a healthy person.
- Never substitute training pads for real patient pads, or vice versa. They are built differently and are not interchangeable.
- Never assume a green light from weeks ago still applies. Self-test results reflect the most recent test only. A unit can pass on Monday and fail by Thursday if a battery drops below threshold.
Why testing alone isn’t the full compliance picture
A device that passes every self-test can still belong to a program that fails an audit, because self-test results, pad and battery dates, certification expirations, and incident records are usually tracked in different places, if they’re tracked at all. The AED compliance mistakes guide covers how these gaps tend to cluster together once a program grows past a couple of devices.
AED Inspections in AED Log logs every monthly check, including the self-test result, alongside battery and pad expirations, certification dates, and incident records, in one dashboard instead of scattered across a clipboard and memory. The goal isn’t to replace the physical self-test — the device still has to run its own diagnostic — it’s to make sure the result actually gets recorded and nothing slips through.
Pricing is tier-based, not per device, so tracking inspections across a growing AED program doesn’t add cost per unit.
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