The previous three articles covered "diagnose" and "do it." This last one is your loss-limit floor — what the scams look like, and which situations you should flatly not attempt yourself.
1. Common repair-market scams (avoid)
Scam 1: "Low on gas, I'll add some" the moment they walk in No testing, no explanation, straight to the upsell. A proper tech checks the filter, outdoor unit, and pressure first — not an instant quote. Hit the 3-step self-check from article 01 before talking money.
Scam 2: Charging without asking the type Mixing R22 with R410A / R32 is catastrophic. Before any work, you check the nameplate type yourself; don't hand over all the control.
Scam 3: Adding without fixing the leak An obvious oily leak, and the tech only tops up without sealing it — that's billing you again next week. Leak repair is basic work; if they won't do it, find someone else.
Scam 4: Billing by "pressure" with inflated amounts "How many pressure units we added" is a line — going by nameplate weight or gauge range is far more reliable. Ask the pricing basis up front.
Scam 5: Overcharging for "instant effect" Cranking pressure too high cools short-term but hurts the compressor long-term. Charge to the normal range, that's the right way.
2. The 5 pitfalls you'll most likely hit doing it yourself
- Wrong type: snap the nameplate photo before buying; R22 / R410A / R32 one wrong character is a world of difference;
- No air purge: air and moisture in the system → ice blockage, corroded compressor;
- Adding without fixing the leak: leak unfixed, gone in a week;
- Overcharge: pressure spikes, high-pressure cutoff, counterproductive;
- Leaky tools: fittings not tight, quick couplers worn — you're "adding" while it leaks out and think it went in.
3. Red lines — call a pro, don't tough it out
In any of these, strongly consider a certified technician — don't DIY:
- ✅ Unit uses R32 / R290 flammable refrigerant — fire/explosion risk, not for amateurs;
- ✅ Outdoor unit is at height, needs working outside a window — fall risk dwarfs the savings;
- ✅ Totally not cooling, suspected compressor or capacitor failure — gas won't fix that;
- ✅ Can't find the leak, keeps going low — needs a leak detector and brazing gear;
- ✅ Involves recovery during a move (pulling the gas back into the outdoor unit) — complex, botch it and you vent all the gas and trash the environment;
- ✅ You're not confident, something feels off — instinct matters most; uncomfortable, stop.
4. Cost reference (so you know the ballpark)
- DIY refrigerant (small R22 cylinder): tens of dollars; R410A / R32: around a hundred;
- Gauge set: tens of dollars, reusable;
- Pro recharge: commonly $40–120 per unit, extra for height, R32, or leak repair.
Do the math: if washing the filter or cleaning the outdoor unit solves it, you save the whole bill; if it's genuinely low and the unit is safe, buying a cylinder yourself pays off over time. But hit a red line, and what you're buying is safety and peace of mind.
5. Series wrap-up
Four articles done: don't panic when it won't cool → 5 signs to self-check → recharge safely → pitfalls and limits.
Three sentences to remember:
- Not cooling ≠ low gas — wash and check first;
- Fix the leak, then add gas;
- R32 / height / compressor failure — just call the pro.
Send these to the person in your house who shouts "add gas!" the second it gets hot. Saves a lot of wasted money.
