Mark’s Kickoff: Let’s Get Our Hands Dirty 🧰
Hey there. Mark here. If you’ve ever installed one of these new R-32 AC and gas furnace systems—or even thought about it—then you know it’s not just plug-and-play. There are refrigerant line specs, furnace clearance codes, dip switches that don’t dip right, and more.
In this post, I’m laying out everything you need to properly install, commission, and troubleshoot a 3–5 ton R-32 AC and gas furnace combo, like the ones over at The Furnace Outlet. These systems pack a punch and run cleaner with that low-GWP R-32 refrigerant—but they come with their own set of quirks.
Let’s roll. 🔧
Step-by-Step Installation: What Works in the Real World
Installing these systems isn’t rocket science, but if you skip a step, you’ll end up chasing error codes or even voiding warranties. Here's my go-to sequence for installs:
1. Site Prep and Furnace Placement
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Always check local codes. Clearance around the furnace needs to be right—especially for combustion air.
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Set your furnace on a solid platform (concrete, blocks, or pre-fab risers).
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Make sure there’s room to service filters, the blower, and ignition controls down the road.
👉 Tip: ASHRAE’s HVAC Applications Handbook gives good specs on airflow and clearance requirements.
2. Run the Line Sets (The Right Way)
R-32 runs at a higher pressure than R-410A, so your line set sizing and insulation matter more than ever.
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Stick with thicker gauge copper tubing, and avoid sharp bends.
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Pressure test with nitrogen and vacuum it down below 500 microns.
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Don’t forget: R-32 is mildly flammable (A2L), so keep leaks to zero.
📘 Here's a great guide from Copeland on handling A2L refrigerants safely.
3. Wire Everything Cleanly
Use a multi-meter like your career depends on it—because it does.
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Match up your thermostat wiring with furnace board terminals.
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Ground everything. Seriously.
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Label low voltage wires and leave a schematic in the panel door for the next poor soul.
4. Configure the Furnace (Board Settings Matter)
Most Goodman and Daikin units have blower speed taps and DIP switch settings. Don’t skip the manual—set it for the right airflow, static pressure, and heating stages.
I’ve seen systems trip out just because the blower CFM was set too low. It matters, folks.
👀 Need a good visual? Check out HVAC School's post on blower setup. Solid stuff.
5. Charge It Up and Check Combustion
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Use weigh-in method for R-32 charging. Subcooling method works too, but weigh-in gets it close.
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Run the furnace through a few cycles.
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Check for proper combustion with a digital analyzer—not your nose.
🚨 Reminder: Always verify manifold pressure and temperature rise. It’s not optional.
Common Troubleshooting Scenarios (And Mark’s Fixes)
Alright, so let’s say something’s not working. Maybe it’s short cycling, maybe no heat, maybe the outdoor unit’s louder than a Harley. Here’s how I handle the top issues I get calls about:
1. Outdoor Unit Won’t Start
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Check capacitor and contactor. If that cap is domed out like a soup can, replace it.
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Test voltage between L1 and L2. You should have 208–230V.
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Is the board flashing? Use the diagnostic codes from the install manual.
➡ Here’s a nice resource from HVAC.com that breaks down common AC issues.
2. Furnace Ignites But No Heat Blows
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Probably a blower motor issue or a limit switch tripping.
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Test the motor windings with continuity. Swap in a known-good capacitor if in doubt.
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Check return air filter. Dirty filter = high limit trips.
3. System Short Cycles or Overheats
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Usually an airflow issue: undersized ducting, clogged filter, or blower not set to proper speed.
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Could also be a flame sensor or rollout switch issue.
🔧 Try cleaning the flame sensor with steel wool. Don’t sand it. Trust me.
4. Weird Smells or Gas Odors
This one’s serious. R-32 has a mild smell if it leaks, but if you smell gas during furnace operation, shut it down and:
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Check all gas fittings with bubble solution.
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Look at the heat exchanger for cracks.
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Never light the furnace again until it's cleared by code.
📚 The National Fire Protection Association (NFPA) has excellent safety codes for A2L and combustion systems.
Mark’s Top Pro Tips 💡
1. Use the Manufacturer’s Support Line
Don't be afraid to call the tech support line. Goodman, Daikin, Carrier—they’ve all got dedicated HVAC tech support. It’s there for a reason. I’ve saved hours on hold vs. guessing on a pressure switch.
2. Take Pictures of Your Work
Sounds dumb? It ain’t. Take a pic of your wiring, gas connection, and board settings before closing up. You’ll thank yourself later if there’s a callback.
3. Tag Your Work
Leave your contact info and install date on a sticker in the unit. If there’s a future issue, they’ll call you instead of someone else.
Why R-32 Is Worth the Effort
R-32 systems are part of the new generation of HVAC tech—better for the planet, better efficiency, and tighter performance. They run at higher pressures, yeah—but they’re also:
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More energy efficient (up to 10% better than R-410A)
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Have a lower Global Warming Potential (GWP) of 675 compared to R-410A's 2088
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Easier to reclaim and reuse
If you're on the fence, check out the EPA’s refrigerant transition page for where everything’s headed. Spoiler alert: R-410A is on its way out.
Mark’s Wrap-Up: You Got This 👊
Look, installing or servicing a 3–5 ton R-32 AC and gas furnace system isn’t for the faint of heart. But if you slow down, follow the sequence, and lean on solid resources (like the ones I linked above), you’ll knock it out like a pro.
These systems at The Furnace Outlet are no joke—they’re efficient, powerful, and built for long-haul performance. Just make sure they’re installed right from Day One. And hey, if you ever run into a snag, just remember what Mark says:
"Don’t guess. Test. Then go get lunch."
Need more installation tips? Visit my guide: The Real-World Checklist for Installing 3.5 Ton R-32 AC and Gas Furnace Systems.
Stay safe out there. Catch ya on the next job. 🛠️
- Mark, your go-to tech
