Panasonic heat pump error codes
12 codes that Panasonic publishes for its heat pumps, each with what it means, the likely cause, what you can safely check and when to call an installer. Tap your code:
Heat pump: do only the checks the maker gives the owner for that code — read the water pressure on the controller, keep the outdoor unit clear of leaves and snow, switch the power off and on where the maker says to. Keep the casing on: refrigerant, wiring and the water circuit’s parts are not owner work. Anything else is for the heat-pump installer or the maker’s service engineer: in the UK and EU only an F-gas certified technician may open the refrigerant circuit. Codes that need one are marked Installer.
Read this first
Panasonic Aquarea air-to-water heat pumps show a fault on the remote controller as a letter and two digits, an H-code or an F-code such as H62 or F12, with the error icon blinking. Panasonic’s operating instructions for the H-generation Aquarea all-in-one (indoor unit WH-ADC0309H3E5 with outdoor units WH-UD03HE5-1 to WH-UD09HE5-1) print a table of 52 codes, each with a short name and nothing more, and give the owner one step for all of them: contact the number registered in the remote controller or the nearest authorised installer. While a code is shown, all buttons but two are disabled. The names below are Panasonic’s own; the line under each says what the name refers to and no more, because this manual gives no causes. Models differ: Panasonic itself notes that some codes may not apply to your model, and your model’s manual is the authority.
H62 Water flow error
- What it means
- The indoor unit reports a fault with the flow of water through it: the heating water is not moving through the hydromodule as it should.
- Likely cause
- Panasonic’s owner manual names the error only and lists no cause.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Contact the number registered in the remote controller, or your nearest authorised installer: that is Panasonic’s one step for every code in this manual.
Source: Panasonic, Operating Instructions, Air-to-Water Hydromodule + Tank, indoor unit WH-ADC0309H3E5, outdoor units WH-UD03HE5-1, WH-UD05HE5-1, WH-UD07HE5-1, WH-UD09HE5-1 (ACXF55-29140, © 2020): Troubleshooting, error code table Checked 2026-10-14.
H20 Pump error
- What it means
- A fault with the pump that circulates the heating water through the hydromodule.
- Likely cause
- Not given in the owner manual.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Contact the number registered in the remote controller, or your nearest authorised installer: that is Panasonic’s one step for every code in this manual.
Source: Panasonic, Operating Instructions, Air-to-Water Hydromodule + Tank, indoor unit WH-ADC0309H3E5, outdoor units WH-UD03HE5-1, WH-UD05HE5-1, WH-UD07HE5-1, WH-UD09HE5-1 (ACXF55-29140, © 2020): Troubleshooting, error code table Checked 2026-10-14.
H75 Low water temperature protection
- What it means
- A protection against water that is too cold has acted. The same manual’s symptom table says, separately, that when the water coming into the unit is below 10 °C the compressor stops and the backup heater switches on; it does not say whether that is what shows H75.
- Likely cause
- Not given in the owner manual.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Contact the number registered in the remote controller, or your nearest authorised installer: that is Panasonic’s one step for every code in this manual.
Source: Panasonic, Operating Instructions, Air-to-Water Hydromodule + Tank, indoor unit WH-ADC0309H3E5, outdoor units WH-UD03HE5-1, WH-UD05HE5-1, WH-UD07HE5-1, WH-UD09HE5-1 (ACXF55-29140, © 2020): Troubleshooting, error code table Checked 2026-10-14.
H70 Back-up heater OLP error
- What it means
- An error from the overload protection (OLP) of the back-up heater, the electric heater that can help the heat pump with space heating.
- Likely cause
- Not given in the owner manual.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Contact the number registered in the remote controller, or your nearest authorised installer: that is Panasonic’s one step for every code in this manual.
Source: Panasonic, Operating Instructions, Air-to-Water Hydromodule + Tank, indoor unit WH-ADC0309H3E5, outdoor units WH-UD03HE5-1, WH-UD05HE5-1, WH-UD07HE5-1, WH-UD09HE5-1 (ACXF55-29140, © 2020): Troubleshooting, error code table Checked 2026-10-14.
H91 Tank heater OLP error
- What it means
- An error from the overload protection (OLP) of the tank heater, the electric heater in the hot-water tank.
- Likely cause
- Not given in the owner manual.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Contact the number registered in the remote controller, or your nearest authorised installer: that is Panasonic’s one step for every code in this manual.
Source: Panasonic, Operating Instructions, Air-to-Water Hydromodule + Tank, indoor unit WH-ADC0309H3E5, outdoor units WH-UD03HE5-1, WH-UD05HE5-1, WH-UD07HE5-1, WH-UD09HE5-1 (ACXF55-29140, © 2020): Troubleshooting, error code table Checked 2026-10-14.
H72 Tank sensor error
- What it means
- A fault with the temperature sensor of the hot-water tank.
- Likely cause
- Not given in the owner manual.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Contact the number registered in the remote controller, or your nearest authorised installer: that is Panasonic’s one step for every code in this manual.
Source: Panasonic, Operating Instructions, Air-to-Water Hydromodule + Tank, indoor unit WH-ADC0309H3E5, outdoor units WH-UD03HE5-1, WH-UD05HE5-1, WH-UD07HE5-1, WH-UD09HE5-1 (ACXF55-29140, © 2020): Troubleshooting, error code table Checked 2026-10-14.
H76 Remote controller to indoor unit communication error
- What it means
- The remote controller (RC) and the indoor unit are not communicating. Panasonic’s name for it is “RC-Indoor communication error”.
- Likely cause
- Not given in the owner manual.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Contact the number registered in the remote controller, or your nearest authorised installer: that is Panasonic’s one step for every code in this manual.
Source: Panasonic, Operating Instructions, Air-to-Water Hydromodule + Tank, indoor unit WH-ADC0309H3E5, outdoor units WH-UD03HE5-1, WH-UD05HE5-1, WH-UD07HE5-1, WH-UD09HE5-1 (ACXF55-29140, © 2020): Troubleshooting, error code table Checked 2026-10-14.
H90 Indoor to outdoor unit communication error
- What it means
- The indoor unit and the outdoor unit are not communicating with each other.
- Likely cause
- Not given in the owner manual.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Contact the number registered in the remote controller, or your nearest authorised installer: that is Panasonic’s one step for every code in this manual.
Source: Panasonic, Operating Instructions, Air-to-Water Hydromodule + Tank, indoor unit WH-ADC0309H3E5, outdoor units WH-UD03HE5-1, WH-UD05HE5-1, WH-UD07HE5-1, WH-UD09HE5-1 (ACXF55-29140, © 2020): Troubleshooting, error code table Checked 2026-10-14.
H98 High pressure protection
- What it means
- The unit’s high-pressure protection has acted. The manual gives the name only.
- Likely cause
- Not given in the owner manual.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Contact the number registered in the remote controller, or your nearest authorised installer: that is Panasonic’s one step for every code in this manual.
Source: Panasonic, Operating Instructions, Air-to-Water Hydromodule + Tank, indoor unit WH-ADC0309H3E5, outdoor units WH-UD03HE5-1, WH-UD05HE5-1, WH-UD07HE5-1, WH-UD09HE5-1 (ACXF55-29140, © 2020): Troubleshooting, error code table Checked 2026-10-14.
H99 Indoor freeze prevention
- What it means
- The indoor unit’s freeze prevention has acted, to keep water in the indoor unit from freezing. The manual also says the backup heater may switch itself on, even when disabled, as protection for the indoor unit’s heat exchanger.
- Likely cause
- Not given in the owner manual.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Contact the number registered in the remote controller, or your nearest authorised installer: that is Panasonic’s one step for every code in this manual.
Source: Panasonic, Operating Instructions, Air-to-Water Hydromodule + Tank, indoor unit WH-ADC0309H3E5, outdoor units WH-UD03HE5-1, WH-UD05HE5-1, WH-UD07HE5-1, WH-UD09HE5-1 (ACXF55-29140, © 2020): Troubleshooting, error code table Checked 2026-10-14.
H42 Low pressure protection
- What it means
- The unit’s low-pressure protection has acted. The manual gives the name only.
- Likely cause
- Not given in the owner manual.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Contact the number registered in the remote controller, or your nearest authorised installer: that is Panasonic’s one step for every code in this manual.
Source: Panasonic, Operating Instructions, Air-to-Water Hydromodule + Tank, indoor unit WH-ADC0309H3E5, outdoor units WH-UD03HE5-1, WH-UD05HE5-1, WH-UD07HE5-1, WH-UD09HE5-1 (ACXF55-29140, © 2020): Troubleshooting, error code table Checked 2026-10-14.
F12 Pressure switch activated
- What it means
- A pressure switch in the system has tripped. The table lists a separate code, F27, for a fault in the pressure switch itself.
- Likely cause
- Not given in the owner manual.
- What you can safely check
Nothing for the owner to check: this one is for an installer.
- When to call an installer
- Installer Contact the number registered in the remote controller, or your nearest authorised installer: that is Panasonic’s one step for every code in this manual.
Source: Panasonic, Operating Instructions, Air-to-Water Hydromodule + Tank, indoor unit WH-ADC0309H3E5, outdoor units WH-UD03HE5-1, WH-UD05HE5-1, WH-UD07HE5-1, WH-UD09HE5-1 (ACXF55-29140, © 2020): Troubleshooting, error code table Checked 2026-10-14.
A code that is not listed here
The rest of the table is mostly sensor errors (H15, H23, H28, H31, H36, H43, H44, H63, H64, H67, H68 and F36 to F49), outdoor-unit protections (F14 to F25) and set-up errors such as H12 capacity mismatch and H38 brand mismatch. Some codes people search for are not in this manual’s table at all — H00, H11, H21 and H97 among them — so they are not explained here. The remote controller keeps an error history (System check, menu 2.3 in this manual) with the newest code at the top, so you can read and pass on a code that has since gone from the screen.
We list only codes the source below states. If your code is not here, it may belong to a model the source does not cover: your model’s manual is the authority.
Related pages
Source
Every code on this page comes from this page, published by Panasonic and read on the date shown. Meanings are written in our own words; nothing is taken from other makes, other models or third-party code sites.