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.
Common Reasons Your Geothermal Heat Pump Stops Working
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
Services brands
Water Furnace
Climate Master