An Expert Guide to Common Heat Pump Problems and Their Solutions
- Geraldine C.
- Aug 20
- 5 min read
Editor's Note: This article was initially published on Aug. 21, 2024 and has been updated in August 20, 2025. The information has been reviewed to ensure its accuracy and relevance for readers in New Zealand.
In New Zealand, heat pumps are a common and cost-effective option for heating and cooling homes. But they can have problems, just like any other appliance. Maintaining the functionality of your system requires an understanding of these typical issues and knowing when to get expert assistance.
OneAir has been keeping Kiwi homes cosy for years as a top supplier of heat pump maintenance and repairs in New Zealand. Because we service and repair thousands of heat pumps every year, we have a thorough understanding of the particular problems that these systems face in our particular climate. Because of our experience, we are able to offer this comprehensive guide on how to maintain, troubleshoot, and maximise the performance of your heat pump.
How Heat Pump Works
Before diving into troubleshooting, it's essential to understand how your heat pump works. A heat pump transfers heat from one place to another, warming your home in winter or cooling it in summer. It comprises two main components: an indoor unit and an outdoor unit.
Common Heat Pump Problems and Solutions
1. Insufficient Heating or Cooling
This is often the first sign of a problem.
Cause: This could be due to dirty air filters, blocked airflow, refrigerant leaks, or a faulty compressor.
Solution:
Check and replace air filters: Regularly inspect and replace dirty air filters to ensure proper airflow.
Clear airflow: Make sure the outdoor unit has at least 300mm of clearance in front and 150mm from the wall behind to allow for proper airflow.
Refrigerant leak: Listen for a hissing sound and look for greasy, oily stains around flare nuts. This requires a professional to detect and repair.
Compressor issues: A faulty compressor requires professional diagnosis and repair.
2. Strange Noises
Don't ignore unusual sounds coming from your unit.
Cause: Loose components, worn-out fan blades, or refrigerant issues.
Solution:
Identify the noise: Try to determine the source of the noise (indoor or outdoor unit). Check for rust.
Loose components: It's generally safe to carefully tighten any loose parts, but do not overtighten critical components like flare nuts. If in doubt, contact a service technician.
Worn-out fan blades: Contact a technician for replacement.
Refrigerant issues: Contact a qualified professional with an Approved Gas Handling Licence.
3. Frozen Evaporator Coil
If you see ice on your indoor unit, you have a problem.
Cause: Insufficient airflow, low refrigerant levels, or a clogged drain line.
Solution:
Check airflow: Ensure proper ventilation around the indoor unit.
Refrigerant levels: Contact a professional for a refrigerant check.
Clogged drain line: Clear the drain line to prevent water build-up. If you're unsure how to do this, call a professional.
4. Frequent Cycling
Your heat pump turning on and off too frequently is a sign something is wrong.
Cause: Dirty filters, thermostat issues, or refrigerant problems.
Solution:
Replace air filters: Clean filters are crucial for optimal performance.
Check thermostat settings: Verify the correct temperature settings and ensure the thermostat is properly calibrated.
Refrigerant leak: Professional inspection and repair are essential.
5. Cool or Lukewarm Air in Heating Mode
If the air isn't warm enough, your system isn't working efficiently.
Cause: Low refrigerant levels, a faulty defrost cycle, or blocked airflow.
Solution:
Refrigerant check: Contact a professional for an evaluation.
Defrost cycle issues: This requires professional diagnosis and repair.
Clear airflow: Remove any obstructions around the outdoor unit.
6. Error Codes
When your system flashes lights, it's trying to tell you something.
Cause: Specific issues are identified by flashing lights on the indoor unit.
Solution: Refer to your heat pump's user manual for a list of error codes or contact a technician.
Heat Pump Preventive Maintenance
Common Heat Pump Problems in New Zealand
New Zealand's climate poses some unique challenges for heat pumps.
1. Corrosion and Salt Damage
Cause: Our many coastal locations and even geothermal areas like Rotorua expose heat pumps to corrosive salty air.
Solution:
Regular cleaning: Regularly wash down the outdoor unit with fresh water to remove salt residue.
Protective coating: Consider a corrosion-resistant coating for the outdoor unit.
Professional inspection: Schedule regular inspections to check for signs of corrosion.
2. Moisture-Related Issues
Cause: New Zealand’s humid climate can lead to condensation and mould growth inside the unit.
Solution:
Proper ventilation: Ensure adequate ventilation around the indoor unit.
Regular cleaning: Clean the indoor unit and drain pan to prevent mould and mildew.
Dehumidification: Consider using a dehumidifier in very damp areas, as the heat pump alone may not be able to manage the humidity.
3. Defrost Mode
This is a normal function but can sometimes be a cause for concern if it happens too often.
Cause: When the outdoor temperature and moisture level are low, ice can form on the outdoor unit, causing it to temporarily turn off to defrost.
Solution:
Defrost cycle: The heat pump's built-in defrost cycle should handle light frost.
Manual defrost: For heavy frost, you can manually defrost the outdoor unit by switching to cooling mode for a short period.
4. Underperformance in Extreme Weather
Cause: Heat pumps generally become less efficient as the ambient temperature drops.
Solution:
Regular maintenance: Ensure your heat pump is in optimal condition to handle weather extremes, especially with correct gas pressure levels.
Supplemental heating: Consider a backup heating source during severe cold snaps.
5. Power Surges and Electrical Issues
Cause: New Zealand's electrical grid can experience fluctuations, which can affect your heat pump.
Solution:
Surge protector: Install a surge protector to protect the unit from power surges.
Professional inspection: Regular electrical checks can help identify potential issues before they cause a breakdown.
When to Call a Professional to Fix Your Heat Pump Problems
It's important to call a professional for more complex problems, even though you can handle some basic ones on your own. An amateur fix frequently results in more harm.
Refrigerant leaks
Complex electrical or mechanical problems
Persistent issues that cannot be fixed by basic troubleshooting
Frequent upkeep and inspections
Do not hesitate to contact the professionals for any heat pump maintenance or repair needs, particularly if you suspect an electrical problem or refrigerant leak. We are available to assist.
In New Zealand, OneAir is a top supplier of heat pump maintenance and repairs. Book your heat pump service for expert and certified professional cleaning and repair.
Frequently Asked Questions
1. How often should I get my heat pump serviced?
Most manufacturers recommend a professional service at least once a year. Regular servicing ensures optimal performance and can help identify minor issues before they become major problems.
2. How do I know if my heat pump has a refrigerant leak?
Signs of a refrigerant leak include a hissing sound, reduced cooling or heating performance, and ice forming on the coils. If you notice any of these, contact a professional immediately.
3. Why is my heat pump's outdoor unit making a loud noise?
A loud noise could be caused by a variety of issues, including loose components, a failing fan motor, or a compressor issue. If the noise is unusual and persistent, it's best to have a technician inspect the unit.
4. Can I clean my heat pump myself?
You can and should perform basic cleaning yourself, such as washing down the outdoor unit and cleaning or replacing the filters. However, deep cleaning the indoor coils and checking the refrigerant levels should be left to a professional.
5. Why is my heat pump using more power than usual?
Increased power consumption can be caused by a number of factors, including dirty filters, low refrigerant levels, or a system that isn't correctly sized for your home. Getting a professional to diagnose the problem is the best way to resolve it.
