What it means
Daikin's guides list it as "OU: PCB defect". Its service manual says it can be reset at the controller or by switching the power off and on.
What to check, in order
- Read the help text
On the controller, open the main menu and choose Malfunctioning to see the code and a short description. The help button gives a longer one. Note the code for your installer.
- Try one power reset
Daikin's service manual says E1-00 can be cleared with a power reset. Daikin UK's user guide says to switch the power off, wait 60 seconds, then turn it back on. If the code comes back, leave it off and call your installer.
- Use emergency heating if you need it
Daikin's user reference guide says the backup heater can take over the heating when the heat pump fails. If emergency mode is set to Manual, you confirm this on the Malfunctioning screen. Expect higher electricity bills while it runs.
When to call your installer
If it comes back, call your installer. Daikin's service manual lists a faulty main PCB, power supply problems, a faulty outdoor fan motor, a faulty or wrongly wired compressor, or heat-sink paste not applied properly on the board.
Quick answers
What does the Daikin Altherma E1-00 error code mean?
The main circuit board in the outdoor unit has found a problem with its memory (EEPROM), so the heat pump has stopped. Daikin's guides list it as "OU: PCB defect". Its service manual says it can be reset at the controller or by switching the power off and on.
Can I fix Daikin Altherma E1-00 myself?
Easy (about 5 minutes). Start with: read the help text; try one power reset; use emergency heating if you need it. If it comes back, call your installer. Daikin's service manual lists a faulty main PCB, power supply problems, a faulty outdoor fan motor, a faulty or wrongly wired compressor, or heat-sink paste not applied properly on the board.
Is Daikin Altherma E1-00 worth repairing?
Get a quote first. If a power reset doesn't clear it, the outdoor board may need replacing, so get a quote.
Checked against
- Daikin Altherma 3 R W installer reference guide 4P496758-1B (ERGA-D, EHBH/EHBX-D), troubleshooting and error codes, p. 89 (ManualsLib copy)
- Daikin Altherma 3 R ECH2O installer reference guide, error codes overview, p. 275 (ManualsLib copy)
- Daikin service manual ESIE20-06A, Daikin Altherma 3 M (EBLA/EDLA), PDF (copy hosted on the OpenEnergyMonitor forum)
- Daikin Altherma low temperature split user reference guide 4P499574-1A (EHVH04/08S23DAV), PDF
- Daikin UK: Daikin Altherma Low Temperature Split Heat Pump user guide (2015), PDF
Last reviewed October 2026. Manufacturers update their pages, and your manual is the final word. Spotted a mistake? Email contact@appliance-error-codes.com.