Why Your Geothermal Heat Pump Isn’t Working — and the Best Service Practices to Keep It Running

Geothermal heat pumps (GHPs) are among the most reliable and efficient HVAC technologies available. But like any mechanical system, they can malfunction—especially if maintenance is neglected. When a geothermal system stops working or fails to heat/cool properly, homeowners often feel lost because the system seems “complicated.” The good news? Most issues have clear causes and straightforward solutions when handled by trained professionals. In this guide, we break down common problems, how to diagnose them, and the best service practices to keep a geothermal heat pump running efficiently year-round.

  1. Low or No Airflow

    A lack of airflow can cause poor heating/cooling or system shutdowns.Possible causes:
    • Dirty air filters
    • Blocked ducts
    • Faulty blower motor
    • Undersized ductwork
    Quick tip: Check and replace filters every 30–90 days.

  2. Low Refrigerant Charge

    Geothermal systems use refrigerant to transfer heat. If you have a leak or low charge, performance suffers. Symptoms:
    • Ice on coils
    • Reduced heat output
    • System short-cycling
    Solution: Only a certified HVAC technician should recharge or repair refrigerant lines.

  3. Loop Circulation Issues

    The ground loop is the heart of a geothermal system. If circulation stops, the system can’t transfer heat. Common causes:
    • Air in the loop
    • Low water flow
    • Pump failure
    • Closed valves
    Technicians should check loop pressure and flow rate during service visits.

  4. Dirty Coils or Heat Exchangers

    Even geothermal systems gather dirt and mineral deposits over time.This reduces efficiency and may cause overheating. Fix: Schedule coil cleaning annually.

  5. Electrical Problems

    From thermostat failures to bad capacitors, electrical issues are common reasons the unit won’t start. Signs include:
    • No power at the unit
    • Tripped breakers
    • Intermittent startup
    A technician should inspect wiring, fuses, and control boards safely.

  6. Faulty Thermostat or Sensors

    Incorrect temperature readings cause frequent cycling or no heat/cooling. Tip: Before calling a pro, try resetting the thermostat or replacing the batteries.

Best Service Practices for Geothermal Heat Pumps

  1. Annual Professional Maintenance

    Unlike conventional HVAC, geothermal systems require a tech who understands loop fields, pumps, and refrigerant flow.
    • A proper annual tune-up includes:
    • Checking loop pressure and flow
    • Testing pumps and motors
    • Cleaning heat exchangers
    • Inspecting the refrigerant circuit
    • Checking thermostat calibration
    • Verifying electrical connections

  2. Monitor Loop Performance Over Time

    Ground loops rarely fail, but when they do, it’s costly. Technicians should:
    • Measure supply/return temperatures
    • Check glycol concentration (if applicable)
    • Track loop pressures annually

  3. Replace Air Filters Regularly

    This is the simplest way to avoid expensive repairs. Recommendation: Use high-quality MERV-rated filters and replace them frequently.

  4. Keep Records of Service History

    Knowing what was replaced and when helps diagnose issues faster.

  5. Ensure Proper Water Quality (Open Loop Systems)

    Mineral buildup and corrosion are major risks. Best practice: Annual water testing and periodic flushing.

  6. Address Issues Early

    Geothermal systems are efficient—so when performance drops, something is definitely wrong.Catching issues early protects your loop, compressor, and pumps.

When to Call a Professional

Call a trained geothermal technician if you notice:
  • Sudden drop in heating/cooling
  • Strange noises from the unit
  • Higher than normal energy bills
  • Water leaks or low loop pressure
  • Ice on pipes or coils
  • System not turning on
Trying to repair geothermal components without proper training can cause serious damage.

Final Thoughts

A geothermal heat pump is an investment that can last 20–30 years with the right care. Understanding why problems happen—and partnering with the right professional—keeps your system operating at peak efficiency and prevents costly breakdowns. Call Air Star Now HVAC. Services brands Water Furnace Climate Master
Perla Wagner