- Heat pumps
- Air-to-water heat pump
P3-04
Daikin Altherma 4 H F P3-04: outdoor abnormal direct current
Risk level
High
Professional inspection is recommended.
Urgency
High
Quick answer
On a Daikin Altherma 4 H F heat pump, code P3-04 means the outdoor unit stopped after exceeding its direct current limit value, with an automatic reset. Check [11] Malfunctioning to see if the unit recovered on its own, leave the breakers ON, and call your installer if P3-04 repeats.
Safety first
Stop and check this first
- Never open the outdoor unit or switch box yourself. Main circuit capacitors retain hazardous voltage after shutdown; a technician must disconnect power for more than 10 minutes and confirm less than 50 V DC before touching any electrical parts.
- After commissioning, do not turn OFF the circuit breakers to force resets when P3-04 appears; turning off the breakers disables freeze protection and pump anti-blockage routines.
Safe checks you can perform
- Check [11] Malfunctioning to see whether P3-04 cleared via its automatic reset
- Inspect [11]: Malfunction history for repeated P3-04, P3-01, P1-00, or L5-00 entries
- Keep circuit breakers ON and check [6.3] Sensors and [5.23] Emergency selection
Leave these tasks to a qualified professional
- Do not attempt this professional task: Discharge capacitors for over 10 minutes (<50 V DC) and inspect the Inverter, Control, and ACS PCBs
- Do not attempt this professional task: Measure outdoor DC current under load and verify that P3-04 does not recur
What a technician must be able to justify
Technician visit
These are the steps they must carry out and show you. Tick them as they work: if steps are skipped, do not accept a part swap.
These are not instructions for opening or handling the equipment yourself. They are the checks that should support a technical conclusion.
Discharge capacitors for over 10 minutes (<50 V DC) and inspect the Inverter, Control, and ACS PCBs
What they doA Daikin certified technician must switch off the main power supply, wait more than 10 minutes, measure less than 50 V DC at the main circuit capacitors before touching switch box parts, and inspect the harnesses and connectors linking the Control PCB, Inverter PCB, and ACS PCB.
They must show youthe voltmeter reading below 50 V DC before touching internal boards and the physical condition of the Inverter PCB and ACS PCB connectors.
In writingthe measured residual capacitor voltage (V DC), the inspection status of the Control/Inverter/ACS PCB wiring, and the incoming AC supply voltage.
Measure outdoor DC current under load and verify that P3-04 does not recur
What they doUsing the Daikin service manual, the technician must measure direct current and compressor winding insulation, replace any faulty sensor or PCB, and run a loaded test cycle to confirm P3-04 no longer trips.
They must show youthe measured direct current and compressor insulation values alongside a clean [11] Malfunction history after the test run.
In writingthe DC current readings, compressor insulation resistance (MOhm), any replaced component part number, and confirmation that P3-04 stays clear.
Before accepting a part or repair
Nothing has been shown yet. Do not accept a part swap based on the code alone.
Follow these steps
Note: Follow the documented order. An error code identifies the affected system, but it does not prove by itself which part has failed.
Check [11] Malfunctioning to see whether P3-04 cleared via its automatic reset
- Who:
- You checking the indoor unit touchscreen display.
- How:
- Open [11] Malfunctioning, tap P3-04 to read the long description, and check whether P3-04 is still listed as an ongoing malfunction or if the heat pump has already restarted automatically.
- Result that matters:
- Determining whether the automatic reset resolved a one-off DC current spike or if the unit remains stopped.
- If P3-04 is no longer ongoing and space heating or hot water is working normally, that indicates an isolated event that cleared automatically.
- If P3-04 stays active on the [11] Malfunctioning screen or returns each time the compressor starts, that confirms a persistent direct current fault requiring your installer.
- Evidence to keep:
- Take a photo of the [11] Malfunctioning screen and note the exact time of the check.
Evidence: Daikin Altherma 4 H F installer reference guide — 4PEN773391-1C · Daikin Altherma 4 H F+W+ECH2O operation manual 4PEN773378-1C
Inspect [11]: Malfunction history for repeated P3-04, P3-01, P1-00, or L5-00 entries
- Who:
- You at the indoor user interface with the user permission level set to advanced end user.
- How:
- Navigate to [11]: Malfunction history and count how many times P3-04 or P3-01 has logged over recent days, and check for companion codes P1-00, L5-00, or L8-05.
- Result that matters:
- Separating a single transient DC limit trip from a repeating outdoor inverter or board communication fault.
- If P3-04 appears multiple times in the history log or alongside L5-00 or P1-00, that confirms automatic resets are not solving the underlying DC current problem.
- If P3-04 appears only once in the history log with no other codes, that rules out a chronic lockout and lets you monitor normal operation.
- Evidence to keep:
- Save a photograph of the [11]: Malfunction history list showing all recorded codes and dates.
Evidence: Daikin Altherma 4 H F installer reference guide — 4PEN773391-1C · Daikin Altherma 4 H F+W+ECH2O operation manual 4PEN773378-1C
Keep circuit breakers ON and check [6.3] Sensors and [5.23] Emergency selection
- Who:
- You at the indoor user interface without touching the outdoor unit or switching off breakers.
- How:
- Do not turn OFF the unit circuit breakers to clear P3-04; instead, read water and tank temperatures in [6.3] Information > Sensors and check [5.23] Settings > Emergency selection if heating drops.
- Result that matters:
- Keeping freeze protection and anti-blockage routines active while verifying whether backup heating is needed.
- If you previously cycled the breaker and P3-04 came right back, that confirms the DC current limit exceedance persists under load and you must stop cycling power.
- If the breakers remain ON and the emergency selection setting enables the backup heater during repeated P3-04 stops, that isolates the outdoor heat pump while keeping indoor water warm until service arrives.
- Evidence to keep:
- Record the [6.3] water temperature readings, any breaker cycles performed, and the dealer phone number from [6.2] Dealer information.
After commissioning, do not turn OFF the circuit breakers to the units and never open the outdoor unit casing.
Evidence: Daikin Altherma 4 H F installer reference guide — 4PEN773391-1C · Daikin Altherma 4 H F+W+ECH2O operation manual 4PEN773378-1C
Still not solved
If the error persists, stop here. See what the technician must do and show you.
Where this code applies
A code is meaningful only inside the right product and version context.
Primary scope
- System
- Heat pumps
- Brand
- Daikin
- Product type
- Air-to-water heat pump
Known code variants
- Altherma 4 H F P3-04
- code erreur Daikin Altherma P3-04
- codice P3-04 pompa di calore Daikin
- código P3-04 bomba de calor Daikin
- Daikin Altherma error P3-04
- Daikin Altherma Fehler P3-04
- Daikin heat pump code P3-04
- Daikin P3-04
- Daikin Wärmepumpe Fehlercode P3-04
- défaut P3-04 pompe à chaleur Daikin
- error Daikin Altherma P3-04
- errore Daikin Altherma P3-04
What it means
In chapter 14.4.4 of the Daikin Altherma 4 H F installer reference guide (4PEN773391-1C), code P3-04 shares the title Abnormal direct current and the trigger Malfunction decision by exceeding direct current limit value with code P3-01. When triggered, the heat pump stops operating and uses an automatic reset, whereas instantaneous DC overcurrent code L5-00 locks out on a manual reset. Because a temporary mains disturbance, internal PCB communication noise (related to P1-00), or compressor load surge can push DC current past its limit, P3-04 alone does not prove the inverter PCB has failed.
Warnings and stop conditions
- Highsource verified
Never open the outdoor unit or switch box yourself. Main circuit capacitors retain hazardous voltage after shutdown; a technician must disconnect power for more than 10 minutes and confirm less than 50 V DC before touching any electrical parts.
Evidence: Daikin Altherma 4 H F installer reference guide — 4PEN773391-1C · Daikin Altherma 4 H F+W+ECH2O operation manual 4PEN773378-1C
- Mediumsource verified
After commissioning, do not turn OFF the circuit breakers to force resets when P3-04 appears; turning off the breakers disables freeze protection and pump anti-blockage routines.
Evidence: Daikin Altherma 4 H F+W+ECH2O operation manual 4PEN773378-1C
Symptoms and causes
Probable causes · in order
- Isolated direct current peak during compressor ramp-up or mains voltage fluctuationCommon
A brief supply voltage dip or heavy compressor load spike pushes the outdoor direct current above its limit value once, after which the automatic reset restores normal operation.
Evidence: Daikin Altherma 4 H F installer reference guide — 4PEN773391-1C
- Recurring DC current exceedance or internal sensing issue on the inverter and ACS PCBsPossible
Repeated P3-04 or P3-01 trips, or companion codes such as P1-00 (transmission between Control, Inverter, and ACS PCBs), L5-00, or L8-05, point to persistent high DC current or degraded current sensing.
Evidence: Daikin Altherma 4 H F installer reference guide — 4PEN773391-1C
- Elevated compressor motor load or outdoor inverter PCB hardware faultLess common
Winding impedance issues on the compressor or a failing DC section on the outdoor inverter PCB keep driving direct current past the P3-04 limit on every restart attempt.
Evidence: Daikin Altherma 4 H F installer reference guide — 4PEN773391-1C
Virtual technician
Does P3-04 still appear after these checks?
Answer a few questions to narrow down the likely cause and the safest next action. Guidance only - it never replaces a professional.
Sources and technical references
- 1
Daikin Altherma 4 H F installer reference guide — 4PEN773391-1C
Daikin Europe N.V. · 2026 · official_doc
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