Troubleshooting guide
Heat pump error code? Here is what is happening and what to do.
Heat pump error codes vary by brand. Mitsubishi codes start with letters (P, E, U); Fujitsu codes are letter+number (E:00, A:01); Daikin uses two-character codes. The unit's blinking lights or display will show the code. Look it up in your owner's manual or call us with the code and we'll diagnose over the phone if we can.
Likely causes, ranked by probability
- 1
Communication error
Indoor-outdoor unit communication fault.
Likelihood 35%
- 2
Sensor failure
Temperature or pressure sensor returning invalid reading.
Likelihood 30%
- 3
Drain or condensate issue
Drain pan sensor triggered.
Likelihood 20%
- 4
Refrigerant pressure fault
High or low pressure switch tripped.
Likelihood 15%
What you can try first
- · Note the exact code and how often it blinks
- · Reset by turning off at breaker for 10 minutes
When to call us: Any error code that returns after a reset.
When a cleaning helps, and when to call a repair pro
A good portion of “something is off” symptoms (musty smell, weak airflow, water dripping from the indoor unit, surface mold) trace back to a dirty blower wheel, clogged drain, or biofilm on the coil. A full disassembly cleaning solves those. If we get on site and find an electrical or mechanical fault (a failing capacitor, a stuck reversing valve, refrigerant issues), we will tell you and recommend a heat pump repair contractor. We do not do repairs ourselves.
Frequently asked questions
Is heat pump error code dangerous?
Most causes of "heat pump error code" are not immediately dangerous, but ignoring them can damage the system over time. Any error code that returns after a reset.
Can a cleaning fix this?
Sometimes. Biofilm, dirty coils, and clogged drain lines often resolve after a deep clean. Mechanical or electrical issues need a heat pump repair contractor instead.
Do you do repairs?
No. We focus on cleaning and twice-yearly maintenance. If your system needs a part replaced or an electrical fix, we will tell you what we see and recommend a repair contractor.
Try a cleaning first.
If the symptom traces back to a dirty unit, we can fix it. If it does not, we will tell you and point you to a repair pro.