Hey folks, Tony here.
Let’s talk about something that doesn’t always make the highlight reel in HVAC blogs but absolutely should—airflow balancing and ECM blower settings, specifically on the Goodman AMST36CU1300 air handler. This step gets skipped too often, and it’s a big reason for poor comfort, high energy bills, and even equipment failure.
If you’re pairing this air handler with the GLXS4BA3610 3-ton R-32 condenser, you’ve got a solid setup—here’s what that bundle looks like—but none of that matters if the air’s not moving right.
Why Airflow Balancing Matters
The AMST36CU1300 is designed to deliver precise airflow, but that’s only half the battle. You’ve got to match that airflow to the ductwork and room load demands. Without balancing:
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Rooms may be too hot or too cold
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System efficiency tanks
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You risk short cycling or even coil freezing
According to This Old House, improper balancing is one of the most common causes of HVAC complaints—and one of the most overlooked steps during install.
Understanding the ECM Motor in the AMST36CU1300
This air handler uses a multi-speed ECM (electronically commutated motor). That’s not just marketing fluff—it means you get better energy efficiency and smoother airflow ramps. But it also means you must configure it properly using the dip switches and cooling CFM settings on the control board.
Key Benefits of the ECM Blower:
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Adapts to static pressure
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Quiet startup and shutdown
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Improved dehumidification
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Higher SEER2 performance potential
If you’re upgrading from a PSC or non-ECM motor, you’ll immediately notice the difference—but only if your installer gets the setup right.
Step-by-Step: How to Balance Airflow with the AMST36CU1300
Let’s get into the process. Here’s what I do on every job.
1. Calculate Required Airflow
The golden rule is 400 CFM per ton of cooling. For a 3-ton system, you’re aiming for around 1,200 CFM total.
But that’s a baseline. You also need to factor in:
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Humid climates (reduce to ~350 CFM/ton)
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High sensible heat loads (increase to ~450 CFM/ton)
2. Measure External Static Pressure (ESP)
Use a manometer to measure across the system. Total ESP should stay below 0.5" w.c. for optimal performance.
Too high? You’ve got a duct restriction. Too low? Your motor may be overdelivering or underloaded.
As Energy Star points out, ignoring ESP can result in misdiagnosis or premature motor failure.
3. Set Dip Switches on the Control Board
On the AMST36CU1300, you’ll find blower configuration dip switches inside the control panel. Refer to the installer manual for:
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Tonnage selection
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Cooling mode (normal, humid, dry climate)
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Delay profile (for dehumidification)
The blower tap settings allow you to match the actual CFM delivery to what your duct system needs. Don’t just leave it on factory default.
4. Test Airflow at Supply Registers
Use an anemometer to measure the face velocity of air at each register. Then calculate CFM:
CFM = Face Area (sq ft) x Velocity (fpm)
Sum up all registers and verify you’re hitting your target (~1,200 CFM). If not, adjust taps or balance dampers.
HVAC Know It All explains this is crucial for identifying rooms that are over- or under-supplied.
5. Balance Supply & Return
Finally, make sure you’ve got:
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Close to equal supply and return CFM
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Return grilles aren’t blocked
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Duct runs aren’t crimped or leaking
If one room’s always uncomfortable, chances are you’ve got a pressure or airflow imbalance. I use balancing dampers and manual adjustments until everything checks out.
Bonus: How to Handle Dehumidification with ECM Settings
In humid zones, you can slow the blower down during cooling startup to help the coil pull more moisture. This means setting the dip switches for a dehumidification delay and choosing a lower CFM-per-ton rate (~350 CFM).
Pairing the AMST36CU1300 with a compatible thermostat that supports dehumidification will make this even easier. Energy Vanguard has a good breakdown of how your settings affect moisture control.
Final Thoughts: The Quiet Power of Fine‑Tuning
Getting your airflow and ECM settings dialed in takes intention—but trust me, it’s where the magic happens. The Goodman AMST36CU1300 air handler paired with the GLXS4BA3610 3‑ton R‑32 condenser is a high-performance combo—but only when installed right. If you’re about to run this system or already have it in place, do yourself a favor and invest that extra 30–45 minutes to balance airflows properly.
Proper airflow tuning delivers more consistent temperatures, cleaner air, better humidity control, quiet operation—and can even stretch the service life of your compressor and blower. If you want to double-check the specs, compatibility, or accessories for this exact match, take a look at the full bundle here: Goodman 3 Ton 14.5 SEER2 System – GLXS4BA3610 + AMST36CU1300.
Need more installation troubleshooting tips for this system? Visit my guide right here!
Stick with the tuning steps I’ve shared—calculate target CFM by tonnage, measure static pressure, configure ECM dip switches, and balance register outputs. Do that, and you’ll have a system that runs smooth, quiet, and efficient for years.
Need help with dip switch settings or airflow verification tools? Drop a comment below or loop in your HVAC pro—comfort tuned the right way is well worth it.
–Tony the Trusted Tech
