Upgrading your HVAC system isn’t just about replacing a condenser or furnace—it’s about ensuring that every component works in harmony. When I decided to replace my old coil with the Goodman 4.5 Ton Horizontal Cased Painted A-Coil with Built-In TXV (Model CHPTA6030D3, R-32 ready), I discovered that the coil is one of the most important but often overlooked parts of the system.
In this guide, I’ll walk you through everything I learned during installation—step by step. We’ll cover planning, tools, safety, refrigerant handling, installation tips, and even maintenance. By the end, you’ll know what it really takes to install this Goodman coil and whether you should DIY or call in a professional.
📋 Why the A-Coil Matters
The evaporator coil (A-Coil) is where the magic happens: refrigerant absorbs heat from the indoor air, cooling your home. If your coil isn’t sized or installed correctly, your entire system’s efficiency takes a hit.
With the shift to R-32 refrigerant, coils like the Goodman CHPTA6030D3 are designed for higher efficiency, lower global warming potential, and compliance with 2025 EPA regulations
🧰 Tools and Materials Checklist
Before I started, I made sure I had all the essentials:
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Adjustable wrench & socket set
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Screwdrivers (flathead & Phillips)
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Tubing cutter
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Brazing torch (for copper connections)
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Nitrogen tank & regulator (for pressure testing)
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Vacuum pump & gauge manifold set
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Safety gear (gloves, goggles, mask)
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Coil cleaner and fin comb
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Sealant & insulation tape
👉 Pro Tip: Even if you’re not DIY’ing, having these on hand helps you understand what your installer is doing.
⚠️ Safety and Prep Work
Installing an A-Coil isn’t like swapping an air filter. You’re dealing with refrigerant lines, electrical connections, and sealed systems. Here’s what I learned:
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Power Down: Always shut off power at the breaker.
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Ventilation: Work in a well-ventilated area when handling refrigerants.
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EPA Certification: Only certified techs can legally handle refrigerants (EPA Section 608).
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Proper PPE: Gloves and goggles protect you from sharp fins and refrigerant burns.
🏠 Step 1: Planning the Installation
I had to confirm the horizontal cased orientation would fit my attic space. Horizontal coils are great for attics and crawlspaces, but you need:
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Clearance: At least 24” for servicing.
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Drain Pan Access: Make sure the coil drains properly—gravity is your friend.
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Compatibility: The Goodman CHPTA6030D3 pairs with 4–5 ton R-32 condensers.
🔗 Goodman has a compatibility chart that helped me verify the match.
🔧 Step 2: Removing the Old Coil
This was messy but necessary:
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Disconnect refrigerant lines (recover refrigerant with EPA-approved equipment).
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Remove screws securing the coil housing.
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Detach drain lines.
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Slide the old coil out carefully.
👉 Tip: Label wires and lines as you go—it’ll save headaches later.
⚙️ Step 3: Positioning the New Coil
The Goodman CHPTA6030D3 comes in a painted horizontal cased cabinet. That made placement easier. Key considerations:
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Leveling: Use a level to ensure the coil sits properly—tilted coils cause drainage issues.
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Insulation: Check for gaps around the cabinet to prevent air leaks.
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TXV Orientation: Since it comes with a built-in TXV (Thermostatic Expansion Valve), you don’t need to add one—but you do need to ensure it’s accessible.
🔩 Step 4: Connecting the Refrigerant Lines
This part requires precision:
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Cut copper tubing to fit.
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Clean and deburr pipe ends.
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Braze connections with nitrogen flowing to prevent oxidation.
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Let connections cool naturally.
🔗 Carrier has an excellent brazing best practices guide I referenced.
💧 Step 5: Drainage Setup
Without proper drainage, coils can flood. I learned to:
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Connect PVC piping to the primary drain pan.
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Install a secondary drain line or float switch (required by many building codes).
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Ensure downward slope for gravity drainage.
🔗 For code compliance, I checked International Mechanical Code (IMC) requirements.
🔌 Step 6: Electrical Connections
The coil itself doesn’t use much power, but you’ll still have low-voltage control wiring:
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Connect thermostat wires to the TXV sensor.
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Check for grounding continuity.
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Secure all wiring with clips to avoid vibration damage.
🧪 Step 7: Pressure Testing and Evacuation
This was where I called in my HVAC pro:
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Pressurized system with nitrogen to 150 psi to check for leaks.
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Pulled a vacuum to 500 microns with a pump.
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Held vacuum for 10 minutes to confirm no leaks.
🔗 Lennox has a refrigerant leak testing guide that’s a great reference.
❄️ Step 8: Charging with R-32 Refrigerant
Since this coil is rated for R-32, my technician charged the system accordingly:
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Used a digital scale to add refrigerant by weight.
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Verified superheat and subcooling values matched Goodman specs.
👉 Fun fact: R-32 has a Global Warming Potential (GWP) of 675, much lower than R-410A’s 2,088 (ASHRAE).
📊 Performance Testing
Once everything was sealed and charged, I checked:
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Airflow: 400 CFM per ton (about 1,800 CFM total).
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Temperature Split: 18–20°F between return and supply air.
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Noise Levels: Noticeably quieter than my old coil.
🛡️ Common Installation Mistakes (and How I Avoided Them)
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❌ Skipping nitrogen purge → Causes black flakes in lines.
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❌ Improper drainage slope → Leads to water damage.
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❌ Overcharging refrigerant → Reduces efficiency and risks compressor failure.
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❌ Mismatched coil and condenser → Always check AHRI match (AHRI Directory).
🧼 Maintenance After Installation
Even the best installation won’t last without care. My seasonal checklist includes:
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Clean coil fins with a no-rinse cleaner twice a year.
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Replace filters every 90 days (or monthly if you have pets).
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Flush the drain line with vinegar solution each spring.
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Inspect insulation and sealant yearly.
🔗 The Department of Energy has a great HVAC maintenance guide.
💵 Costs I Encountered
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Coil unit: $850–$1,200 (Goodman direct pricing).
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Installation labor: $1,200–$2,000 depending on region.
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Additional parts (drain, insulation, brazing supplies): $150–$300.
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Total: Around $2,500–$3,500 all in.
✅ Final Takeaways
Installing a 4.5 Ton Goodman A-Coil with built-in TXV isn’t a weekend DIY project unless you have HVAC training. But as a homeowner, learning the process gave me confidence to:
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Ask the right questions of my installer.
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Verify that the work was done correctly.
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Understand how my system actually cools my home.
If you’re considering this upgrade, my advice is: do the research, know your space, and don’t skimp on quality installation.
In the next topic we will know more about: What Does a Built-In TXV Mean for Your AC System? Efficiency & Performance Explained
