Safety Center
Every diagnosis this tool gives is written around three rules it will never bend. Read these once, and you'll always know why a step says "call a pro."
If this is happening right now
Gas smell, smoke, sparking, or a carbon monoxide alarm sounding: leave the property immediately. Do not flip switches, do not troubleshoot, do not use this tool. Call 911 or your local gas utility from outside, and don't go back in until emergency responders say it's safe.
Rule One
Refrigerant is not a DIY part
Under EPA Section 608 of the Clean Air Act, purchasing, handling, or recovering refrigerant legally requires certification. This isn't a suggestion — it's federal law, and it exists because refrigerant is hazardous to handle without the right equipment and training.
When the diagnostic tool identifies refrigerant as the likely issue — low charge, a leak, or a failed metering device — it will say so plainly and point you to a licensed, EPA-certified technician. It will never walk you through gauges, recovery, or recharging.
- What's DIYChecking for ice on lines, confirming airflow, noting symptoms to describe to a tech.
- What isn'tConnecting gauges, releasing refrigerant, topping off charge, replacing a metering device.
- Why it mattersImproper handling can cause chemical burns, frostbite, and environmental harm — and it's illegal without certification.
Rule Two
Power off before anything electrical
Any step that touches wiring, a capacitor, a contactor, or the inside of an electrical panel starts the same way: cut power at the breaker, and at the outdoor disconnect if your unit has one, then confirm it's actually off before proceeding.
Capacitors are worth calling out specifically — they store a high-voltage charge even after power is cut, and discharging one safely takes the right tool and technique. That's why capacitor and contactor work in this library is marked "call a pro" rather than walked through step by step.
- AlwaysBreaker off, disconnect pulled, confirmed off before opening any panel.
- NeverWorking on a "live" system to save a trip to the breaker panel.
- CapacitorsTreated as pro-only in every guide, even when the fix looks simple.
Rule Three
Gas and carbon monoxide get evacuated, not diagnosed
A gas smell or a sounding CO alarm is never treated as a troubleshooting prompt. Combustion equipment — gas furnaces, gas water heaters near your HVAC system — carries risks that require leaving the area first and asking questions second.
If your CO alarm has gone off, treat it as real even if no one feels symptoms yet. Get everyone outside, then call from a safe distance.
CO poisoning symptoms to know
Headache, dizziness, weakness, nausea, confusion, or chest pain in multiple household members at once — especially if it improves after leaving the house. If anyone shows these signs, call 911.
General Practice
Baseline safety for anything you do touch
Wear the basics
Safety glasses and gloves for any panel work, even "simple" filter changes near sheet metal edges.
One hand rule
Near any live panel you're not 100% sure is de-energized, keep one hand in your pocket to avoid a path across your chest.
Know your limit
If a step in this library or the diagnostic tool says "call a pro," that's the answer — not a challenge.