Troubleshooting Guide: What to Do If Your Goodman Air Handler Isn’t Heating or Cooling Properly

Even reliable units like the Goodman 2 Ton R-32 Compatible Wall-Mounted Air Handler (Model AWST24SU1308) can sometimes stop heating or cooling the way they should. Before panicking—or calling in an HVAC technician—you can often solve the problem by checking a few common culprits.

Mark, our DIY-inclined homeowner, learned this the hard way:

“Last summer my air handler stopped cooling. I thought I was in for a $500 repair. Turns out it was just a clogged filter. I felt pretty dumb—but also relieved. Since then, I always check the basics first.”

This troubleshooting guide will walk you through what to do if your Goodman air handler isn’t working right—starting with simple DIY fixes and moving up to issues that require professional help.

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🔍 Step 1: Start with Airflow

Poor airflow is the most common cause of an air handler not heating or cooling properly.

What to check:

• Filter condition: Dirty filters block airflow and reduce efficiency.

• Registers & vents: Make sure they aren’t blocked by furniture, rugs, or dust.

• Ductwork: Check for visible leaks, collapsed ducts, or closed dampers.

👉 According to Energy Star, replacing filters every 1–3 months can reduce energy consumption by 5–15% and prevent system strain (Energy Star Maintenance Guide).

Mark’s tip:

“The filter is always the first thing I check now. It’s cheap and easy—and it’s saved me from unnecessary service calls.”

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💧 Step 2: Inspect the Drain Line

Air handlers generate condensation during cooling. If the condensate drain is clogged, a safety switch may shut down the system to prevent overflow.

Signs of a clogged drain line:

• Water pooling around the unit.

• Drip pan full or overflowing.

• Unit won’t turn on even though power is available.

Fixes:

• Use a wet/dry vacuum at the drain outlet to suck out clogs.

• Flush the line with vinegar or a cleaning solution.

• Check slope—should drop at least ¼ inch per foot.

👉 The DOE notes that condensate issues are one of the most common causes of HVAC service calls (DOE Energy Saver).

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🔌 Step 3: Verify Power & Thermostat

Sometimes the simplest problems are electrical.

Checklist:

• Breaker box: Check for tripped breakers. Reset if needed.

• Disconnect switch: Ensure the service switch near the unit is on.

• Thermostat: Make sure it’s set to “Heat” or “Cool,” and the temperature setting is correct.

• Batteries: If your thermostat runs on batteries, replace them.

Mark’s story:

“I once thought my unit was dead, but my thermostat batteries were just out. Five dollars later, everything worked again.”

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❄️ Step 4: Look for Frozen or Dirty Coils

If your air handler runs but doesn’t cool, the evaporator coil may be dirty or frozen.

Signs of coil problems:

• Ice buildup on the coil or refrigerant lines.

• Reduced airflow at vents.

• Warm air instead of cool.

Fixes:

• Turn off the system and let ice thaw completely.

• Replace the filter to restore airflow.

• Clean coil with coil cleaner spray or soft brush.

👉 The ACCA stresses regular coil cleaning to prevent freeze-ups and maintain efficiency (ACCA Standards).

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⚡ Step 5: Consider Electrical or Component Failures

If your Goodman air handler still isn’t heating or cooling after airflow, drain, and thermostat checks, the issue may be with internal components.

Possible culprits include:

• Blower motor failure – No airflow at all.

• Capacitor or control board failure – Unit won’t start.

• Heater kit malfunction – No backup heat in winter.

• TXV or refrigerant problem – Poor cooling performance.

These issues generally require a trained technician.

👉 The Building Performance Institute (BPI) highlights electrical and mechanical failures as leading causes of HVAC downtime (BPI Resources).

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🛠️ When to Call a Pro

While many issues are DIY-friendly, some require professional expertise:

• Refrigerant leaks (R-32 requires EPA Section 608 certified handling).

• Repeated tripped breakers – could indicate electrical hazards.

• No airflow even with a new filter.

• Strange noises or burning smells.

👉 The EPA Section 608 rule requires certification for refrigerant handling to protect homeowners and the environment (EPA Section 608).

Mark says:

“I’ll unclog a drain or swap a filter myself. But if refrigerant’s involved, I don’t mess around. That’s a pro’s job.”

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🏠 Mark’s Troubleshooting Routine

Mark keeps his process simple:

1. Check filter → Replace if dirty.

2. Inspect thermostat → Verify settings & batteries.

3. Look at drain line → Flush if clogged.

4. Check breaker/disconnect → Reset if tripped.

5. Inspect coil → If iced, power off and thaw.

6. Call pro → If system still doesn’t heat or cool.

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🪟 Common Mistakes to Avoid

• Jumping straight to refrigerant assumptions. Most issues are airflow-related.

• Ignoring water leaks. A small puddle can lead to mold or structural damage.

• Running unit with frozen coil. This can damage the compressor.

• Skipping maintenance. Seasonal care prevents most troubleshooting calls.

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💲 Cost of Fixes

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📋 Quick Troubleshooting Checklist

✅ Is the filter clean?
✅ Are vents open and unobstructed?
✅ Is the thermostat set correctly?
✅ Is the breaker on?
✅ Is the drain line clear?
✅ Is the coil clean and unfrozen?

If all are checked and the system still doesn’t work, it’s time for professional service.

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📊 Infographic Idea

“Goodman Air Handler Troubleshooting Flowchart”

• Start: “Unit not heating/cooling?”

• Step 1: Check filter → Clean/replace.

• Step 2: Check thermostat → Correct setting?

• Step 3: Check drain line → Clear blockage.

• Step 4: Check coil → Frozen? Thaw & clean.

• Step 5: Still broken? → Call a pro.

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💡 Mark’s Final Takeaway

Mark sums up his approach:

• “Always start with the simple stuff—filters, thermostats, breakers. Nine times out of ten, that’s the fix. If not, that’s when you call in a pro. Don’t risk making it worse by guessing with refrigerant or electrical work.”

By following these troubleshooting steps, you can often fix minor issues yourself and know when it’s time to call for professional help—keeping your Goodman air handler running efficiently and reliably.

In the next topic we will know more about: Cost Breakdown: Equipment, Accessories & Installation for the AWST24SU1308