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November 3, 2025

Larwill, IN Heat Pump Not Cooling? 5 Likely HVAC Causes

Estimated Read Time: 9 minutes

Your heat pump not cooling on a humid Huntington afternoon is more than a nuisance. It can mean high bills, uneven rooms, and stress on the system. Below are the top five reasons a heat pump stops cooling, how to fix each, and when to call Summers Plumbing Heating & Cooling for 24/7 help. Use these steps to stay safe, protect your warranty, and restore comfort fast.

Start Here: Quick Safety and Smart First Steps

A heat pump is an all‑season system that cools by moving heat out of your home. When cooling drops off, start with safe checks you can do in minutes:

  1. Verify power at the thermostat and the indoor breaker. Reset once.
  2. Confirm the thermostat is set to Cool and the fan is on Auto.
  3. Replace a dirty filter. A clogged filter can ice the coil and kill cooling.
  4. Clear debris from the outdoor unit. Keep 18–24 inches of open space.
  5. Give the system 10–15 minutes to stabilize after any change.

If breakers trip again, you see ice on the indoor coil, or you hear hissing near the lineset, stop and schedule service. Those signs point to issues that can damage the compressor.

Reason 1: Thermostat or Control Settings Are Off

What it looks like:

  • System runs but rooms stay warm.
  • Fan blows but air is not cold.

Likely causes:

  • Thermostat in Heat, On, or Program Hold that ignores your setpoint.
  • Incorrect schedule, dead batteries, or sensor placement in direct sun.
  • Smart thermostat misconfigured for heat pump with or without auxiliary heat.

Homeowner fixes:

  1. Set mode to Cool and fan to Auto. Target 72–75°F for testing.
  2. Replace batteries and disable any vacation hold.
  3. Move heat‑pump specific settings to the correct configuration. Many smart stats need the reversing valve set to O/B correctly and auxiliary heat stages mapped.

When to call:

  • The thermostat is wired for a heat pump but still will not switch to cooling.
  • The system short cycles after correct settings. That can be a control board or outdoor sensor fault.

Pro tip for Huntington homes: South‑facing entries along the Wabash River corridor get strong afternoon sun. If your thermostat sits near that heat, readings can be 2–4 degrees high. A remote room sensor or a relocation solves the problem.

Reason 2: Dirty Outdoor Coil or Blocked Airflow

What it looks like:

  • Lukewarm air from vents.
  • Outdoor unit runs constantly. The top fan may sound strained.
  • Higher summer electric bills.

Why it happens:

  • Cottonwood fluff, grass clippings, and dust clog the outdoor coil.
  • Landscaping or fencing blocks airflow. Heat pumps need breathing room.

Homeowner fixes:

  1. Shut off power. Gently hose the coil from inside out if the panel allows safe access. Never pressure wash.
  2. Trim shrubs to maintain 18–24 inches of clearance on all sides and five feet above.
  3. Keep pets and mulch away from the base to prevent debris recirculation.

When to call:

  • Fins are matted or bent, or the fan motor squeals. Professional fin combing and amp checks prevent compressor damage.

Why maintenance matters: A clean coil can restore 10–15 percent of lost capacity. Our precision tune‑up includes coil cleaning, fan capacitor testing, and refrigerant performance checks to recover cooling and reduce runtime.

Reason 3: Low Refrigerant or a Refrigerant Leak

What it looks like:

  • Air feels cool at startup, then warms quickly.
  • Ice on the indoor coil or the refrigerant lines outside.
  • Bubbling or hissing sounds near the lineset.

What to know:

  • Heat pumps are sealed systems. They do not use up refrigerant. If it is low, there is a leak.
  • Running low can overheat the compressor, the most expensive part of your system.

Homeowner steps:

  • Turn the system off if you see ice. Let it thaw completely. Do not chip ice.
  • Replace the filter and resume cooling only if the coil is clear and airflow is normal.

Professional repair:

  • We perform a nitrogen pressure test or electronic leak search, repair the leak, verify vacuum to industry standards, then weigh in the exact factory charge.

Warranty note: Many manufacturers require proof of annual service to keep refrigerant and parts coverage intact. Our maintenance agreement helps you satisfy this requirement automatically and documents each visit for your records.

Reason 4: Frozen Indoor Coil or Restricted Airflow

What it looks like:

  • No cooling, weak airflow, or visible frost on the copper near the air handler.
  • Water around the furnace or air handler when ice melts.

Common causes:

  • Dirty filter, closed supply registers, or collapsed return duct.
  • Blower motor or capacitor failure that reduces airflow.
  • Oversized systems short cycling during humid Huntington summers.

Homeowner fixes:

  1. Replace the filter. Open all supply registers fully.
  2. Check for crushed flex duct runs in attics or basements.
  3. If icing occurs, shut the system off and run fan only to defrost.

When to call:

  • Repeated icing after a new filter. We check blower speed, static pressure, coil cleanliness, and charge to find the root cause.

Comfort tip: In our area, humidity along the Wabash can spike after thunderstorms. A properly set blower speed and clean coil are crucial for drying the air. That is why our tune‑up includes airflow measurement and coil inspection, not just a quick rinse.

Reason 5: Reversing Valve, Defrost, or Control Board Failure

What it looks like:

  • The system heats when it should cool, or air feels neutral no matter the mode.
  • Outdoor unit stops occasionally and steams or sizzles in cooling season.
  • Random error codes on the thermostat.

What’s happening:

  • The reversing valve directs refrigerant flow for heating or cooling. If it sticks or loses the pilot signal, cooling disappears.
  • Defrost control or sensor faults can interrupt cooling or cause odd cycles.
  • A failing control board or contactor can start and stop the compressor unpredictably.

Why you need a pro:

  • Testing these parts requires gauges, temperature probes, and manufacturer procedures. Guessing can lead to a compressor failure.

Our diagnostic approach:

  1. Confirm proper low and high side pressures against outdoor ambient.
  2. Check coil temperatures and superheat/subcooling to verify flow.
  3. Test O/B signal, defrost board logic, and contactor voltage drop.
  4. Provide a clear repair or replacement path with upfront pricing.

Preventive Maintenance That Actually Saves Money

Skipping maintenance lets heat pumps lose capacity slowly, which means longer run times and higher bills. Our precision tune‑up targets the biggest efficiency leaks:

  • Outdoor and indoor coil cleaning for heat transfer.
  • Refrigerant performance check and electrical testing.
  • Thermostat calibration and airflow measurement.
  • Drain, condensate safety, and defrost system checks.

Why homeowners join our maintenance program:

  1. Prioritized status and one‑day replacement services when needed.
  2. No overtime charges, even for after‑hours emergencies.
  3. Regular tune‑ups scheduled automatically at enrollment, so you never forget.
  4. Discounts on repairs and equipment that can offset the plan cost.
  5. Helps you maintain warranty compliance with documented service.

Bottom line: In many Huntington homes we service, a clean coil and corrected charge cut summer runtime by 20–30 minutes per day while improving comfort in back bedrooms.

What to Expect From Our Heat Pump Service in Huntington

Whether you are near downtown Huntington, out toward Roanoke, or along US 24 toward Wabash, we tailor service to your home and schedule.

Our process:

  1. Discovery: We listen to symptoms, run a full cooling diagnostic, and check your duct system.
  2. Options: You get clear choices with upfront pricing before work starts. No surprises.
  3. Fix or Improve: We repair what failed, and we explain ways to prevent repeat issues.
  4. Follow‑through: You receive documentation for your records and warranty.

Why Summers:

  • 40+ years of experience serving residential and light commercial heat pumps.
  • One‑year labor and manufacturer warranty on HVAC equipment and services.
  • 24/7 emergency availability for no‑cool situations.
  • Flexible financing options for major repairs or replacements.

If we find that replacement is smarter than repair, we size the new system properly, address duct bottlenecks, and balance air so every room gets cooling, not just the hallway.

DIY vs Professional: Make the Right Call

Do it yourself safely:

  • Filters, basic thermostat settings, and outdoor debris removal.
  • Rinsing a lightly dusty coil with garden hose pressure from the outside.

Call a licensed pro for:

  • Refrigerant issues, electrical problems, repeated icing, or control failures.
  • Odd smells, tripped breakers, or signs of arcing at the disconnect.
  • Systems that needed refrigerant last year and are low again. That is a leak.

The goal is not just to restore cooling today. It is to protect the compressor, hold down utility costs, and extend system life through the hottest Huntington weeks.

Quick Checklist: Is Your Heat Pump Not Cooling?

  1. Thermostat in Cool, fan on Auto, schedule correct.
  2. New filter installed, vents open, returns unobstructed.
  3. Outdoor unit clean and clear on all sides.
  4. No ice on lines or coil. If present, power off and defrost.
  5. Still warm air after 15 minutes? Call Summers for diagnostics.

When you are ready, we can also examine insulation, attic ventilation, and duct losses that keep second floors warmer than main levels. Fixing these small items often unlocks the comfort you expected when you bought the system.

Reviews

What Homeowners Are Saying

"Complete installation of heat pump and air conditioning. Very professional and qualified technicians who were very friendly!"
–James P., Heat Pump Installation
"Joel came out and cleaned and serviced our geothermal unit. He explained what he was doing and made suggestions. I was very impressed with his service."
–Roger S., Geothermal Service

Frequently Asked Questions

Why is my heat pump not cooling but the fan is running?

This often points to wrong thermostat mode, a dirty outdoor coil, or a refrigerant problem. Confirm Cool mode, replace the filter, clear debris, then test. If airflow is weak or air is still warm, schedule a diagnostic.

Can low refrigerant damage my heat pump?

Yes. Low charge overheats the compressor and can cause a costly failure. Heat pumps are sealed systems, so a low charge means a leak. Shut the system off if you see ice and call for leak testing and proper charging.

How often should a heat pump be serviced in Huntington?

At least once a year, ideally before cooling season. Our precision tune‑up cleans coils, checks charge and electrical parts, and verifies airflow. Annual service helps maintain manufacturer warranty coverage.

Should I hose off my outdoor unit?

Gently rinsing light dust is fine. Turn power off first and avoid pressure washers. If fins are matted with cottonwood or bent, you need professional cleaning to prevent damage and restore airflow.

When is replacement smarter than repair?

Consider replacement when repairs approach 30–40 percent of a new system, the unit is over 12 years old, or you face a major component failure like a compressor. We provide load sizing and options with financing.

In Summary

A heat pump not cooling usually comes down to settings, airflow, refrigerant, or a control fault. Start with the simple checks above, then lean on our team for fast, warrantied repairs. We know Huntington’s humidity and how to dial in comfort room by room.

Ready for Relief? Call Now

Get same‑day troubleshooting from Summers Plumbing Heating & Cooling. We back repairs with a one‑year labor and manufacturer warranty and offer 24/7 emergency service.

Restore cool, dry comfort today with a trusted local team serving Huntington, Marion, Bluffton, and beyond.

About Summers Plumbing Heating & Cooling

For 40+ years, Summers Plumbing Heating & Cooling has helped Huntington homeowners stay comfortable with honest pricing and proven workmanship. Our licensed, background‑checked technicians service all makes and models. We back our work with a one‑year labor and manufacturer warranty on HVAC equipment and services, offer 24/7 emergency support, and provide flexible financing options. Expect clear estimates, options that fit your home, and respectful service from a local team that knows the US 24 corridor, lake‑effect humidity, and Huntington County’s seasonal swings.

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