Troubleshooting Guide: What to Do If Your Heat Pump Isn’t Cooling or Heating

🏡 1. Jake’s Story: When the Cool Air Stopped

Last summer, I woke up to a surprise — my Goodman heat pump wasn’t cooling. The thermostat said 72°F, but the air coming out of my vents was warm and muggy.

“Great,” I thought. “It’s Saturday, it’s 90° outside, and the house feels like a greenhouse.”

Like most homeowners, my first reaction was panic — followed closely by thoughts of expensive repairs. But before calling a technician, I remembered what I tell my own customers all the time: start with the basics.

👉 Explore the Goodman 3 Ton 15.2 SEER2 Heat Pump System
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Within 20 minutes, I had cool air again. The culprit? A dirty air filter and a tripped outdoor breaker.

In this guide, I’ll walk you through exactly what I did — and what every homeowner should check first if their heat pump isn’t heating or cooling properly. You’ll learn how to safely troubleshoot, spot simple fixes, and know when it’s time to call a pro.

Because most of the time, it’s not a major failure — it’s just a small issue you can solve yourself.

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🔌 2. Step 1: Check the Thermostat and Power

Before you grab your tools, start at the wall. Many cooling or heating issues begin with the thermostat or power supply.

✅ Thermostat Settings

• Make sure it’s set to the correct mode — “Cool” in summer, “Heat” in winter, or “Auto” if you want it to switch automatically.

• Verify the fan setting is on “Auto,” not “Off.” If you only hear air but no temperature change, the compressor may not be running.

• Double-check the temperature setting — especially if someone recently adjusted it or used a “Hold” function.

⚡ Power Checks

If your thermostat screen is blank, start with power:

1. Replace thermostat batteries (if your model uses them).

2. Check your home’s breaker panel — heat pumps have two breakers: one for the outdoor unit (condenser) and one for the indoor air handler.

3. Reset both breakers by switching them fully off and back on.

4. Wait about 5 minutes to allow your Goodman system’s time-delay relay to reset before testing again.

If the system still doesn’t power up, the issue might involve a tripped disconnect switch near the outdoor unit or a blown fuse in the air handler.

“In my case, the outdoor breaker had tripped during a thunderstorm. Flipping it back on instantly brought the system to life.”

📘 Reference: Energy.gov – Heat Pump Systems Basics

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💨 3. Step 2: Inspect Air Filters and Airflow

Clogged air filters are the #1 reason homeowners think their heat pump has failed.

If your system runs but struggles to cool or heat effectively, always check the filter first. Dirty filters restrict airflow, causing:

• Reduced efficiency

• Frozen coils

• Overheating in heating mode

• High electric bills

🔍 How to Check

1. Turn off the system at the thermostat.

2. Open the access panel on your Goodman vertical air handler (model AMST30BU1300).

3. Slide the filter out and inspect it under light. If it looks gray or dusty, replace it.

Goodman systems perform best with MERV 8–11 filters, replaced every 60–90 days.

“Once, my airflow dropped by half because my reusable filter was caked in dust. Five minutes and one clean filter later — problem solved.”

📗 Reference: Goodman – Air Filter Maintenance Tips

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❄️ 4. Step 3: Check for Ice or Frost on the Outdoor Unit

If your outdoor condenser looks like it’s been through a snowstorm — even in July — you may have a frozen coil problem.

🧊 What It Means:

• In cooling mode, ice buildup means restricted airflow or low refrigerant.

• In heating mode, light frost is normal — the system enters a defrost cycle every 30–90 minutes to melt it.

🧯 What to Do:

1. Turn off the system.

2. Switch the thermostat fan setting to “On.”

3. Wait 1–3 hours for the ice to melt naturally.

4. Replace the filter and clear any obstructions around the outdoor unit.

If the ice returns quickly, you might have a refrigerant leak — time to call a licensed technician.

“I once found my Goodman condenser encased in ice because my outdoor coil was packed with cottonwood fluff. A simple rinse fixed it.”

📘 Reference: Energy Star – Common HVAC Issues

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🧏 5. Step 4: Listen for Unusual Noises

A quiet Goodman system is normal — a noisy one is not. The sounds it makes can tell you exactly what’s wrong.

“When I heard a faint clicking every few seconds, I removed my thermostat faceplate and found a loose wire. Tightened it, and boom — problem solved.”

Never ignore grinding or hissing — those point to mechanical or refrigerant issues that can worsen if left unchecked.

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🌬️ 6. Step 5: Inspect Outdoor Coil and Fan Operation

The outdoor condenser is where much of your heat pump’s work happens. Dirt, debris, or mechanical issues here can halt cooling or heating efficiency.

🧹 Visual Inspection:

• Ensure the fan blades spin freely when the unit runs.

• Check for leaves, mulch, or pet hair blocking the sides or coil.

• Keep at least 24 inches of clearance around the unit.

💦 Cleaning Tip:

Turn off the breaker, then gently rinse the coil fins using a garden hose (no pressure washer!).
Avoid bending fins — they help release heat efficiently.

If you notice oil stains or burnt wiring, stop and call a pro — that could indicate compressor damage.

 

🔄 7. Step 6: Check Defrost and Reversing Valve Operation

The reversing valve is the “brain” behind your heat pump’s dual functionality — switching refrigerant flow between heating and cooling.

🧠 Common Symptoms:

• System blows cold air in heat mode.

• System blows warm air in cooling mode.

• No temperature change when switching modes.

To test:

1. Switch from “Cool” to “Heat.”

2. Listen for a distinct “whoosh” — that’s the valve changing direction.

3. If you hear nothing or get no temperature change, the valve or defrost board may be stuck or malfunctioning.

“When my unit didn’t heat one winter, the reversing valve coil connector had come loose — an easy $0 fix once I found it.”

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💧 8. Step 7: Check Drain Lines and Float Switch

When your heat pump runs in cooling mode, it removes humidity from the air — that water drains through a condensate line.

If that drain clogs, the float switch in your Goodman air handler will shut off the system to prevent flooding.

🧼 How to Clear It:

1. Turn off the system.

2. Locate the white PVC drain near the air handler.

3. Remove the cap and pour in a 50/50 mix of vinegar and water.

4. Let sit for 10 minutes, then flush with warm water.

5. Reset the system and test operation.

If your system restarts, congratulations — you just fixed one of the most common “no-cool” issues for free.

📗 Reference: Cleaning an AC Drain Line

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⚠️ 9. Step 8: When to Call a Pro

If you’ve checked everything above and your Goodman heat pump still isn’t cooling or heating, it’s time to call in an expert.

Here are the red flags:

• Refrigerant leak (hissing sound, low pressure, frozen coil)

• Electrical failures (breaker keeps tripping)

• Defrost board issues (no mode change, outdoor unit freezes)

• Compressor not starting (buzzing but no fan movement)

• System short cycling (on-off every few minutes)

“Knowing when to stop troubleshooting is just as important as knowing where to start. DIY repairs beyond filters and drains can void your warranty.”

A certified Goodman technician can test refrigerant pressures, check control boards, and run diagnostics to find the root cause quickly.

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💵 10. What Common Repairs Cost in 2025

Here’s what you can expect for average service pricing this year:

📘 Reference: 2025 Heat Pump Repair Costs

“When I priced out repairs, I realized the lifetime compressor warranty on my Goodman saved me $1,800 — the kind of protection you want.”

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🧰 11. Preventive Tips: Keep It Running Smoothly

The best way to avoid future problems is regular maintenance.

Here’s my personal checklist — the same one I use for customers:

🗓️ Every 1–2 Months:

• Change filters (MERV 8–11).

• Inspect indoor vents for blockage.

🧽 Every 6 Months:

• Rinse condenser coil with a hose.

• Clear leaves and debris around outdoor unit.

• Flush condensate drain line.

🧑🔧 Once a Year:

• Schedule a professional inspection and refrigerant check.

• Clean indoor blower and check electrical connections.

• Calibrate thermostat for accurate readings.

📗 Reference: Energy Star – Maintenance Checklist

“A little seasonal attention keeps your system efficient — and helps catch small issues before they turn into expensive ones.”

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🔋 12. Understanding Goodman’s Diagnostic Features

Goodman’s 2025 models — like the GSZB403610 — are built for smarter troubleshooting.

• LED error codes on the control board indicate faults.

• Pressure sensors monitor refrigerant flow.

• Smart defrost logic adjusts automatically to weather conditions.

If you see a blinking LED on your air handler or condenser, check your Goodman manual — it can often tell you exactly what the problem is.

“When my fan stopped running, the diagnostic light blinked three times — the code for a bad capacitor. My tech confirmed it and fixed it within an hour.”

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🧠 13. Pro Tips for DIY-Friendly Homeowners

1. Label breakers for easy identification later.

2. Keep a maintenance log of filter changes and repairs.

3. Invest in a smart thermostat to monitor system performance.

4. Trim shrubs near your outdoor unit twice a year.

5. Always turn off power before touching the system.

“HVAC isn’t rocket science — it’s routine care and paying attention to small details.”

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🧊 14. Winter Troubleshooting: When It Won’t Heat

If your Goodman heat pump runs but doesn’t warm your home in winter, focus on:

• Reversing valve (stuck position or failed solenoid).

• Defrost cycle (outdoor coil stays frozen).

• Backup heat (electric strips or gas furnace not engaging).

Set your thermostat to “Emergency Heat.” If warm air flows, your heat pump’s heating side needs attention — not your air handler.

📘 Reference: Energy.gov – Dual-Fuel Systems Overview

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☀️ 15. Summer Troubleshooting: When It Won’t Cool

If your system blows warm air instead of cool:

• Check thermostat mode and setpoint.

• Confirm condenser fan runs when compressor engages.

• Look for ice on the refrigerant lines.

• Ensure no tripped breaker or blown fuse.

If everything checks out, the issue could be a low refrigerant charge — which only a professional can safely correct.

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🧾 16. Preventing Future Failures

A heat pump’s lifespan is directly tied to care. Here’s what affects longevity most:

• Clean filters = optimal airflow

• Balanced refrigerant = stable operation

• Dry coils = reduced corrosion

• Professional maintenance = extended life

Jake’s 3-ton Goodman SEER2 system is now 5 years old — and still runs like new.

“I tell homeowners: your system will take care of you, if you take care of it.”

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💡 17. When It’s Time to Replace Instead of Repair

If your heat pump is:

• Over 12–15 years old

• Uses outdated R-22 refrigerant

• Has rising repair bills

• Lacks variable-speed technology

…then it may be time to consider upgrading. The latest Goodman SEER2 models provide up to 20% energy savings and qualify for federal tax credits.

📗 Reference: Energy Star – 2025 Heat Pump Tax Credits

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💬 18. Jake’s Final Thoughts: Stay Calm, Stay Smart

“When your heat pump stops cooling or heating, it feels urgent. But 80% of the time, it’s something small — a filter, a tripped breaker, or a dirty coil.”

Knowing what to look for helps you stay in control and saves hundreds on service calls.
With a little patience and the right information, you can troubleshoot confidently — and keep your Goodman system running strong.

In the next topic we will know more about: Noise, Clearance & Placement Tips: Where Jake Installed His Outdoor Unit