Brownsburg Heat Pump Not Cooling? 5 Reasons

Estimated Read Time: 9 minutes

If your heat pump is not cooling, you feel it fast. Rooms get muggy, temperatures drift, and your utility bill climbs. In this guide, we break down the top causes, how to troubleshoot safely, and when to call a pro. You will learn practical fixes, prevention tips, and what Brownsburg homeowners can expect from a proper tune‑up and repair visit. You will also see how correct sizing and setup keep comfort steady even on humid Indiana days.

Quick Safety Check Before You Start

Heat pumps rely on electricity and refrigerant. Turn off power at the disconnect or breaker before removing panels. If you smell burning, see ice forming on lines, or the breaker keeps tripping, stop and call a professional.

• Confirm the thermostat is set to Cool and the setpoint is at least 3 degrees below room temperature.
• Make sure supply and return vents are open and furniture is not blocking airflow.
• Inspect the outdoor unit for debris, leaves, or cottonwood fluff. Keep 2 to 3 feet of clearance.

“Great job!!! He came out fixed our issue, helped us understand things on our heat pump! Very helpful!”

Reason 1: Airflow Restrictions Choke Cooling

Insufficient airflow is the most common reason a heat pump stops cooling well. A dirty filter starves the system of air, which causes the indoor coil to get too cold and sometimes ice over. Blocked returns, closed supply vents, crushed flex duct, or a failing blower motor will produce the same symptoms: weak airflow, uneven room temperatures, and longer run times.

What to do now:

1. Replace or clean your filter. In summer, check it monthly.
2. Open all supply vents. Close only if a technician balanced the system for zoned airflow.
3. Look for sagging or disconnected duct runs in attics, crawl spaces, or basements.
4. Listen for blower issues. Whining, scraping, or a blower that ramps up and down may signal a failing motor or control board.

Prevention: Keep registers clear, schedule professional duct inspections every few years, and ask for a static pressure test. Many Brownsburg homes have older ductwork sized for furnaces that does not always match a modern heat pump’s airflow needs. A quick test can confirm if your system is breathing freely.

“Needed a second opinion on a heat pump repair/replace decision. Josh came out and did a nice thorough investigation, explained things in an easy to understand way... Now that the gremlins have been vanquished, the unit has worked flawlessly.”

Reason 2: Dirty Coils Kill Efficiency

Your heat pump cools by absorbing heat at the indoor coil and dumping it at the outdoor coil. Dust, pet hair, pollen, and cottonwood cling to these coils. Even a thin film reduces heat transfer, forcing longer cycles and warmer indoor air. On muggy Hendricks County days, a dirty outdoor coil can make the difference between crisp cooling and a system that never catches up.

DIY steps:

1. Turn power off. Remove big debris around the outdoor unit.
2. Rinse the outdoor coil from the inside out using gentle water pressure. Do not bend fins.
3. Let the unit dry fully, restore power, and test cooling.

Professional maintenance goes further. During a tune‑up our technicians complete a full cleaning and performance check. As our team says, “The basic steps of a professional tune‑up include: Cleaning the indoor and outdoor coils to optimize energy efficiency, checking refrigerant levels and looking out for possible leaks, inspecting and tightening all electrical connections, calibrating the thermostat for accurate temperature control, lubricating moving parts, clearing the condensate drain line, testing the defrost feature and reversing valve, and changing or cleaning air filters.”

Reason 3: Low Refrigerant or a Leak

Refrigerant is the lifeblood of your heat pump. Low charge due to a leak means poor heat absorption and longer run times. Signs include ice on the refrigerant lines or indoor coil, hissing near the line set, or a system that cools right after a restart but fades fast.

What to do now:

• Do not keep cycling the unit if you see ice. Turn it off, let it thaw, and call a pro.
• A licensed technician should perform a leak search, repair the leak, pull a deep vacuum, and weigh in the correct refrigerant charge. Guesswork here wastes money and risks compressor failure.

Fact to know: Proper charge is measured against manufacturer specifications. It is verified through superheat, subcooling, and performance readings. This ensures you get the capacity you paid for and protects the compressor.

Reason 4: Thermostat, Sensors, or Control Failures

A miscalibrated thermostat or faulty sensor can trick your system into short cycling or running in the wrong mode. Loose low‑voltage wiring, a stuck contactor, or a failed capacitor can also stop the outdoor unit while the indoor blower keeps running. The result is warm air at the vents.

Try this first:

1. Replace thermostat batteries if present and confirm system mode is Cool.
2. Set the fan to Auto, not On, to avoid pushing warm air when the outdoor unit is off.
3. Check the breaker and outdoor disconnect. A half‑tripped breaker needs a firm reset off and on.

If the outdoor fan does not spin, you may have a failed capacitor or contactor. These are quick professional fixes. Summers offers 24/7 emergency response so you are not stuck waiting in the heat.

Reason 5: Reversing Valve or Defrost Issues

Heat pumps switch between heating and cooling with a reversing valve. If the valve sticks or the defrost board is malfunctioning, the system may run in the wrong mode or stall. You might feel lukewarm air, hear odd cycling, or notice the outdoor unit sound change sharply.

This is a technician job. We test valve operation, coil temperatures, and control board logic. We also verify the defrost cycle. When set up correctly, your system cools smoothly and stays efficient.

Other Causes Worth Checking

• Incorrect sizing: An undersized unit will run nonstop and never reduce humidity. Our team sizes equipment considering square footage, insulation, window load, and local design temperatures.
• Duct leakage: Leaky return ducts pull hot attic air straight into the system. A duct smoke test or pressure test finds losses fast.
• Old equipment and efficiency: New heat pumps with high SEER2 and HSPF ratings deliver more cooling per watt. Quiet operation and smart thermostat compatibility improve comfort and control.
• Mini‑split setup: Ductless heads with dirty filters or misdirected vanes produce poor room cooling. Clean filters and set vanes for a gentle downward sweep across the room.

What a Professional Heat Pump Tune‑Up Includes

Most manufacturers recommend maintenance twice a year, spring and autumn, because heat pumps work year‑round. Our Brownsburg team follows a detailed process and documents readings so you can see performance improving.

A proper visit includes:

1. Coil cleaning indoors and outdoors.
2. Refrigerant check with superheat and subcooling readings.
3. Electrical inspection and tightening.
4. Thermostat calibration and control checks.
5. Lubrication of moving parts where applicable.
6. Clearing the condensate drain line to prevent water damage.
7. Testing the defrost feature and reversing valve.
8. Filter replacement or cleaning.

Benefits you notice:

• Lower energy bills and stronger cooling.
• Fewer surprise breakdowns due to early problem detection.
• Longer equipment life and healthier indoor air.
• Safety checks that catch hazards before they become emergencies.

As we say on our service pages, “If you sign up for a maintenance plan, our team will remind you when it’s time for your next service and offer priority scheduling so you never have to worry.”

DIY Fixes You Can Try Today

• Replace the air filter and clear debris around the outdoor unit.
• Gently rinse the outdoor coil. Let it dry before restoring power.
• Confirm thermostat settings. Replace batteries and set fan to Auto.
• Open all supply vents and clear returns. Move furniture that blocks airflow.
• Check the breaker. If it trips again, stop and call for service.

If these steps do not restore cooling within an hour, professional diagnostics will save time and money.

How Summers Diagnoses Cooling Problems the Right Way

Brownsburg humidity, cottonwood season, and attic duct runs create a unique load profile. Our technicians start with a short interview, then measure static pressure, temperature split, and electrical values. We check charge by the book, sized against manufacturer targets. When replacement is the right choice, we match your home with the correct capacity and focus on SEER2 and HSPF ratings, quiet operation, and smart thermostat compatibility.

We handle every stage, from install to maintain to repair to replace, and we offer true 24/7 emergency service so you never wait long for help.

Considering an Upgrade? Options That Improve Summer Comfort

• High‑efficiency air‑source heat pumps: Better SEER2 and variable‑speed compressors remove more humidity and keep temperatures steady.
• Dual‑fuel systems: Automatically switch to a gas furnace during rare cold snaps for top comfort and efficiency.
• Ductless mini‑splits: Perfect for bonus rooms or additions with no ductwork.
• Geothermal systems: Loops buried in the yard tap stable ground temperatures. Geothermal heat pumps can achieve efficiencies three to five times greater than conventional furnaces and A/C units, which can translate into major utility savings.

Financing and strong warranties are available. We provide clear, upfront quotes with no hidden fees. You will know your options before work starts.

When to Call a Professional Immediately

• Ice on refrigerant lines or the indoor coil.
• Burning smells, frequent breaker trips, or loud electrical buzzing.
• Outdoor fan not spinning or short cycling every few minutes.
• Water around the air handler from a clogged drain line.

Fast action prevents compressor damage and water issues. Our vans are staged across Brownsburg, Avon, Zionsville, and nearby communities for rapid response.

Real‑World Results From Local Service Calls

“Jason arrived on time. He introduced himself as he walked up to my door... He answered my questions honestly which was a surprise. My service appointment was supposed to be for the furnace and heat pump... not the A/C!!”

“Travis was the technician that performed my inspection and eventual replacement of our water heater. He was very courteous and professional, and did a great job on the install. Their staff was even able to coordinate with AES to obtain a heat pump water heater rebate.”

Even when another company is involved, honest diagnostics protect your wallet and comfort. Our goal is the right fix the first time.

Local Details That Matter in Hendricks County

• Cottonwood fluff clogs outdoor coils in late spring. A pre‑summer rinse can preserve cooling capacity.
• Many homes have return grills undersized for modern equipment. Adding a return or upsizing grills can drop noise and improve airflow.
• Crawl space duct runs sweat in humid weather if not sealed and insulated. A quick inspection reduces moisture and energy loss.

Two hard facts to keep in mind:

1. Manufacturers and HVAC pros recommend heat pump maintenance twice per year because the system heats and cools your home.
2. Our company holds Plumbing License C05130016 and staffs certified HVAC technicians who follow documented diagnostic and tune‑up procedures.

Frequently Asked Questions

Why is my heat pump running but not blowing cold air?

Airflow restrictions, a dirty outdoor coil, or a failed outdoor component can stop cooling while the blower runs. Check the filter, open vents, and confirm the breaker. If air is warm after these steps, call a professional.

Can low refrigerant damage my heat pump?

Yes. Low charge causes the coil to freeze and the compressor to overheat. Continued operation can lead to compressor failure. Turn the system off and schedule a leak check and recharge by a licensed technician.

How often should a heat pump be serviced?

Twice per year. Schedule a spring cooling tune‑up and an autumn heating tune‑up. Heat pumps work in both seasons, so biannual service keeps efficiency and reliability high.

Should I set my fan to On or Auto in summer?

Use Auto for most homes. Fan On can push warm air when the outdoor unit is off and raise humidity. Auto allows proper dehumidification and more stable comfort.

When is replacement better than repair?

Consider replacement if repairs exceed 30 percent of replacement cost, the unit is 10 to 15 years old, or it uses outdated refrigerant. New high‑SEER2 systems cool better and lower bills.

Conclusion

If your heat pump is not cooling, start with airflow and coil cleaning, then check settings and power. When issues persist, professional diagnostics protect your comfort and your compressor. For fast, honest service in Brownsburg and nearby, call Summers Plumbing Heating & Cooling at (317) 765-1855 or schedule at https://www.summersphc.com/brownsburg/. We offer upfront pricing, strong warranties, and 24/7 emergency help to get your home comfortable again.

Ready to Get Cool Again?

Call (317) 765-1855 or book online at https://www.summersphc.com/brownsburg/ for same‑day heat pump service. Ask about maintenance plans with reminders and priority scheduling. Serving Brownsburg, Avon, Zionsville, Plainfield, and surrounding communities.

About Summers Plumbing Heating & Cooling: We are the local, 100% employee‑owned team Brownsburg trusts for honest, upfront pricing and certified workmanship. Our technicians are trained to install, maintain, and repair heat pumps, ductless mini‑splits, and geothermal systems. We offer 24/7 emergency service, financing options, and strong parts and labor warranties. With decades of local experience and thousands of 5‑star reviews, we size equipment correctly, explain your options clearly, and stand behind the results. Plumbing License: C05130016. Serving Brownsburg, Avon, Zionsville, and nearby communities.