How to Handle Heat Pump Error Codes?
Your heat pump is flashing an error code on the display, and you're wondering if it's time to panic or if you can fix it yourself. The good news: most error codes tell you exactly what's wrong, and many issues can be solved in minutes.
Understanding what each code means puts you in control. You'll know whether it's a quick fix like cleaning a filter or a job that needs a professional technician—and you'll save time, stress, and money.
What Are Heat Pump Error Codes?
Think of an error code as your heat pump's way of calling for help. When something goes wrong—a sensor fails, airflow gets blocked, refrigerant pressure drops, or a component malfunctions—the system displays a code on its controller or display panel.
These codes consist of letters and numbers. A code like E1 or P2 or H3 each means something specific. Some codes appear with a red LED or warning icon, making it obvious something needs attention. Others trigger a silent malfunction where your system just stops heating as efficiently as it should.
Common Heat Pump Error Codes and What They Mean
Different manufacturers use different codes, but the problems they signal are similar across brands. Here's what you might see:
Sensor Errors (E1, E2, E3)
These codes point to faulty temperature sensors. E1 might indicate an indoor temperature sensor issue, while E2 could point to an outdoor sensor problem. When sensors misread, your heat pump can't regulate temperature properly, and efficiency drops.
Quick check: Look for visible ice or frost on the outdoor unit. Clear it gently with warm water (not boiling). If the code persists after a reset, call a professional—sensor replacement typically requires a technician.
Fan and Airflow Errors (F1, F2, F3)
A blocked fan, dirty filters, or restricted airflow triggers these codes. In Eastern Ontario winters, snow and debris around your outdoor unit are common culprits.
Quick fix: Clear a 2-foot radius around the outdoor unit. Replace your furnace filter if it's dirty. Remove leaves, twigs, or snow blocking the intake vents.
Pressure Issues (P1, P2, P3)
These codes signal that refrigerant pressure is too high or too low. Low pressure often means a leak or blockage; high pressure usually means restricted water or airflow.
What to do: Check for ice buildup on coils (defrost cycle should handle this, but blockages prevent it). If filters are clogged or outdoor coils are dirty, clean them. If the code returns after a reset, you likely have a refrigerant leak—call a professional immediately. This isn't a DIY fix.
Heating System Faults (H1, H2, H3)
These errors indicate issues with the heating process itself—problems with the outdoor unit, compressor delays, or communication errors between components.
First steps: Reset the system by turning it off for 5 minutes, then back on. Check that all cables and connections to the outdoor unit are intact and not damaged by weather or pests. If the error persists, a technician needs to diagnose the compressor or electrical circuit.
Different manufacturers use different codes, but the problems they signal are similar across brands. Here's what you might see:
Sensor Errors (E1, E2, E3)
These codes point to faulty temperature sensors. E1 might indicate an indoor temperature sensor issue, while E2 could point to an outdoor sensor problem. When sensors misread, your heat pump can't regulate temperature properly, and efficiency drops.
Quick check: Look for visible ice or frost on the outdoor unit. Clear it gently with warm water (not boiling). If the code persists after a reset, call a professional—sensor replacement typically requires a technician.
Fan and Airflow Errors (F1, F2, F3)
A blocked fan, dirty filters, or restricted airflow triggers these codes. In Eastern Ontario winters, snow and debris around your outdoor unit are common culprits.
Quick fix: Clear a 2-foot radius around the outdoor unit. Replace your furnace filter if it's dirty. Remove leaves, twigs, or snow blocking the intake vents.
Pressure Issues (P1, P2, P3)
These codes signal that refrigerant pressure is too high or too low. Low pressure often means a leak or blockage; high pressure usually means restricted water or airflow.
What to do: Check for ice buildup on coils (defrost cycle should handle this, but blockages prevent it). If filters are clogged or outdoor coils are dirty, clean them. If the code returns after a reset, you likely have a refrigerant leak—call a professional immediately. This isn't a DIY fix.
Heating System Faults (H1, H2, H3)
These errors indicate issues with the heating process itself—problems with the outdoor unit, compressor delays, or communication errors between components.
First steps: Reset the system by turning it off for 5 minutes, then back on. Check that all cables and connections to the outdoor unit are intact and not damaged by weather or pests. If the error persists, a technician needs to diagnose the compressor or electrical circuit.
Brand-Specific Error Codes You Might Encounter
Daikin
Code U0 signals a refrigerant shortage, which typically requires an F-Gas-certified technician to either refill the system or repair leaks. Daikin systems also commonly display A6 (outdoor temperature sensor error) and J6 (indoor fan motor issue).
Mitsubishi Ecodan
Mitsubishi Ecodan systems are popular and commonly display U1 and P1 errors caused by blocked filters or low flow rates. These are Eastern Ontario favorites because they perform well in cold climates. If you see U1, check your filters first. [doc_4]doc_4
Bosch
Bosch heat pumps have fault codes like E01 (low pressure), E02 (high pressure), and E03 (compressor temperature too high). E02 often means your water circulation is restricted—check for clogged filters or air in the system.
LG
CH14 relates to low water flow, usually caused by blocked filters or issues with the hydraulics of the system. CH19 signals a compressor problem and requires professional diagnosis.
NIBE
Alarm 294 signals a temporary power loss to the outdoor unit (reset and recheck). Alarm 220 points to circulation issues, often caused by clogged filters or valves.
Panasonic
Error H62 indicates a problem with water flow, usually due to low flow rates or blockages.
Common AquaCal Heat Pump Error Codes
AquaCal heat pumps also come with their own set of error codes, some of which are related to pressure, temperature, and communication issues. Here’s what you might encounter:
Low Pressure Errors (LowPressure, LP5 Lockout): These indicate a refrigerant pressure problem, often due to blocked airflow, dirty coils, or ice buildup. To troubleshoot, clear any blockages, check for frost, and clean or replace pool filters if necessary.
High Pressure Errors (HighPressure, HP5 Lockout): These codes show that the refrigerant system is under high pressure. Common causes include clogged filters or restricted water flow. Make sure the filters are clean, and if needed, increase the pump speed to improve flow.
Temperature-Related Errors (HighWaterTemp, OverTempAlarm): These errors are triggered when the incoming water temperature exceeds 108°F. To resolve, check if any external heat sources (like solar heaters) are affecting the water temperature, and allow it to cool before resetting the breaker.
Communication Issues (SmartComms, MultiUnitComms): These codes indicate problems with communication between the heat pump and external controllers or between multiple units. Make sure the wiring is intact and the external controller is set up correctly. If you're unsure, contact your installer or technician.
Other Issues (SourceFlow, VariableDrive, LowClockBattery): These codes point to problems like no detected water flow, issues with the variable speed compressor drive, or a failing clock battery. Each problem requires specific actions, such as checking water flow, resetting the breaker, or replacing the battery.
Why Maintenance Prevents Most Error Codes
Here's what we've learned over years of servicing heat pumps in Kingston and Eastern Ontario: Lack of maintenance and systems not inspected in over a year are more likely to experience buildup, sensor problems, and declining performance.
Regular maintenance—typically twice yearly (spring and fall)—catches issues before they become error codes. A technician will:
Clean condenser coils and filters
Check refrigerant pressure and levels
Test sensors and electrical connections
Inspect for leaks or damage from weather
Systems on ECM's maintenance plan get priority attention and catch problems early, often preventing costly repairs down the road.
READ MORE…
How Heat Pumps Work in Extreme Cold?
How to Install an Air-to-Water Heat Pump in Kingston?
How to Tell If Your Heat Pump Is Stuck in Cooling Mode and How to Fix It?
If you notice any issues, don’t hesitate to contact ECM! We offer professional HVAC services, including expert heat pump maintenance and seasonal checks to keep your system running smoothly all year round. So sit back, relax, and let us ensure your home stays cozy and comfortable!
