Outdoor and wash‑down environments can expose weak links in an emergency light. This hands‑on guide gives you a clear, repeatable workflow to diagnose wet‑location emergency lights—covering power/charger checks, battery tests, water‑ingress fixes, cold‑weather failures, and remote‑head circuits. For fundamentals on ratings and where each device type fits, see the Wet‑Location Emergency Egress Guide.
Last updated: October 2025
Safety & tools
- Lockout/tagout the branch circuit before opening housings. Observe wet‑location practices when working in rain or wash‑down areas.
- Tools: multimeter, insulated screwdriver set, torque driver, replacement gaskets/fasteners per model, silicone‑approved for electrical use, lint‑free wipes.
- Have the unit’s spec label handy (system voltage, battery type, temperature range, enclosure rating).
Diagnostic workflow (5 steps)
- Visual scan: Check for broken lenses, missing screws, loose conduit hubs, or signs of moisture; confirm indicator LED state.
- AC power & charger: Verify feed at the terminal block; inspect fuses; confirm the charger output is present and indicator behavior matches the legend.
- Battery health: Inspect for swelling/leaks. Confirm connections and rated chemistry/voltage match the label. If runtime is short, replace the pack with the specified type.
- Lamp heads/boards: Reseat connectors; swap heads (A↔B) to isolate head vs. driver; replace failed LED boards or sealed heads as needed.
- Seal & re‑test: Reassemble, ensure gaskets are uniformly compressed, perform a 30‑second test, and schedule a 90‑minute verification.
Tip: For ongoing care, pair this with the Maintaining Weatherproof Emergency Lights checklist to prevent repeat failures.
Symptoms → likely cause → fix
| Symptom | Likely Cause | Recommended Fix |
|---|---|---|
| No illumination on test | No AC feed; tripped breaker/fuse; failed charger; open battery circuit | Verify power at terminals; replace blown fuse; check charger output; reseat battery leads; replace charger module if no output |
| One head dark or flickering | Loose connector; water in head; failed LED board/driver | Dry/replace sealed head; re‑terminate connector; replace LED module/driver; re‑aim and torque pivots |
| Runs < 90 minutes | Aged battery; excessive remote‑head load; cold temperature below rating | Install new specified battery; reduce remote load/add unit; add heater/low‑temp option; see Cold‑Weather Emergency Lights |
| Condensation or water inside lens | Compromised gasket; unsealed knockout; upward‑facing seam; uneven torque | Replace gasket; seal knockouts with listed liquid‑tight fittings; correct orientation; torque screws evenly in a cross pattern |
| Indicator shows persistent fault | Battery fault; charger fault; lamp fault logged by self‑test | Follow legend to identify fault class; replace module or battery; clear code and re‑run test |
Cold‑weather failures
At low temperatures, battery output drops and plastic becomes brittle. Verify the fixture’s minimum ambient rating and whether a low‑temperature pack or internal heater is installed. In harsh winters or freezers, it’s often smarter to keep the battery indoors and power exterior remote heads. For selection and layout guidance, see Cold‑Weather Emergency Lights.
Remote heads & voltage‑drop
- Confirm the system voltage on the label (e.g., 6/12/24 VDC) and total remote‑head wattage is within the unit’s allowance.
- Keep wire runs short and size conductors to limit voltage‑drop; balance loads across outputs.
- Symptoms of excessive drop: dim heads, early runtime loss, or nuisance faults. Re‑calculate, upsize wiring, or add another remote‑capable unit.
- For design trade‑offs between remote heads and integrated devices, read Remote Heads vs Integrated (Outdoors).
Water‑ingress triage
- Open housing; photograph evidence of moisture for records.
- Remove power; dry the enclosure and boards with lint‑free wipes and gentle airflow—avoid heat guns.
- Replace damaged gaskets; re‑seal conduit entries with listed liquid‑tight fittings; ensure weep/drain orientation is correct.
- Replace any water‑exposed batteries or rusted hardware; reassemble and test.
Repair vs. replace
- Repair when enclosure and lens are intact, faults are isolated (battery, board, or gasket), and the model is still supported with parts.
- Replace when housings are cracked/UV‑damaged, repeated water ingress persists, parts are obsolete, or required options (heater, remote capacity) are missing for the application.
- If a door also requires an EXIT legend outdoors, consider a wet‑rated combo to reduce device count; details at the Outdoor Combo Units Guide.
Test records & AHJ
- Document monthly 30‑second tests and an annual 90‑minute discharge per unit ID, with corrective actions and initials.
- Attach spec sheets and temperature ratings to work orders for exterior/freezer locations.
- After repairs, perform a full 90‑minute verification and log results for inspection.
Resources
FAQ
The unit passes the 30‑second test but fails the 90‑minute test. Why?
Battery capacity is likely diminished or remote‑head load is too high. Replace the specified battery and confirm remote load/wire sizing. Re‑test for the full duration.
The indicator shows a charger fault. Can I swap boards cross‑model?
No—use the manufacturer’s specified replacement for the model/voltage. Cross‑model boards may not meet UL 924 listing.
We keep seeing condensation after storms. What should we check first?
Gasket compression and conduit entries. Replace gaskets, torque screws evenly, and ensure the housing orientation allows drains/weep holes to function.