Fd, FC, UU and P1 to P4 codes in Junkers: reset, keys, low voltage and initialization

Your Junkers is displaying Fd, FC, UU, or a sequence like P1, P2, P3… and you're not sure whether to worry. If you see the Fd error Junkers, the short answer is that it's usually one of the most harmless codes: most likely, a button has been stuck, the mains voltage is low, or the appliance is simply starting up. In many cases, these issues are resolved in minutes without any tools.

However, there are a couple of cases where they might be hiding something more. We'll explain each code, what it usually indicates based on our experience, and what to check if they appear repeatedly.

JunkersFd Error: The reset button

boiler Junkers locks out due to a fault (EA, E9, F7…), you must press the reset button to restart it. The Fd error code usually appears when the control board detects an incorrect reset button press: either there was no fault to reset, or the button was held down for too long. This is usually easily resolved by pressing the button again normally.

If the Fd Junkers error appears without anyone having touched anything, you need to find out why the board "thinks" that the button is pressed:

• The front panel or the casing is pressing the button. This is very common right after a service: when the cover is reattached, it's slightly misaligned and presses the button. Check that the front panel is properly seated.
• The key is stuck due to grease and kitchen grime, preventing it from returning to its position.
• Moisture on the control panel: can cause the hob to register a persistent pulse. This occurs in kitchens with a lot of steam or if water falls onto the boiler.
• Finally, a faulty push button on the board.

FC: keys pressed on the HydroPower-Plus

This is the equivalent of the "Fd" on the HydroPower-Plus water heater (WTD…KG): it usually indicates that one of its buttons has been pressed for more than 30 seconds. The usual causes are the same: a stuck button, a poorly positioned front panel, or moisture on the panel. Release the button, clean the panel with a slightly damp cloth, and dry it thoroughly.

US: Low electrical voltage

In Eur(MFA versions), UU usually indicates that the supply voltage has dropped below 185V. Normally, the boiler is not faulty: it protects itself and restarts automatically when the voltage is correct. If this happens repeatedly:

• Plug the boiler directly into the wall, without extension cords or power strips.
• Check if it coincides with the start-up of powerful appliances (oven, induction hob, electric water heater) on the same line.
• In rural homes or at the end of a long power line, voltage may drop during peak hours. If this happens, the problem could be with the grid, and you should report it to your electricity distributor.
• An electrician can measure the voltage and check the condition of the installation.

In the Ceraclass Midi, low voltage is usually indicated by a different code: E0. We explain this in the F0, E0 and b1 plate code.

P1, P2, P3, P4: the boiler is starting up

On Euromaxx boilers Eurthese codes usually appear in sequence when the boiler is initializing: after connecting it to the power supply or after a power outage. Normally, no action is required; as soon as it finishes, it returns to the normal display. It's only a problem if the boiler gets stuck on one of these codes or restarts repeatedly, which could indicate power outages or a problem with the circuit board.

Fd Junkers error and other codes depending on the model: the usual

In our experience, this is what each code usually means depending on the appliance family:

• Eur: Fd, reset key activated without fault: usually press again. P1, P2, P3, P4: usually initialization. UU (MFA only): voltage probably below 185 V; usually starts when the power supply is correct.
• EurAcu-Hit: Fd, reset button that appears to be permanently pressed: usually it is enough to reset it.
• Ceraclass Excellence / Cerastar: Fd, reset that appears to have been pressed for more than 30 seconds.
• Cerapur, Comfort, Excellence and Acu: Fd, reset pressed by mistake in many cases.
• HydroPower-Plus: FC, keys that have usually been pressed for more than 30 seconds.

What you can do

• Press the reset button once, normally, without holding it down.
• Check that the front panel is properly fitted and is not pressing any buttons.
• Clean the control panel with a slightly damp cloth and dry it thoroughly.
• Plug the device directly into the wall.
• Wait for the initialization to finish after a power outage.

If the code returns after all this, the problem may be in the button or the circuit board, and that is the job of an authorized technician.

Related spare parts

Controls and front panels:

• Controls for ZW24, ZW23 and ZS Eurline boilers (87020002730)
• Controls for Ceraclass Midi ZW24 (87020003080)
• Control unit for ZWA24, ZWC and ZWBC boilers (8716012555)

If the problem turns out to be the circuit board, you have the references in the circuit board code and on all spare parts Junkers.

Frequently Asked Questions

How many times can I press the reset button?

In case of a malfunction, try this once or twice. If the device locks up again, don't keep resetting it: you should try to find the cause of the code that locked it.

The Fd Junkers error appeared right after the annual service. Have they damaged something?

The faceplate is most likely not properly seated and is pressing the reset button. Reseal it before calling.

Can UU damage the boiler?

The boiler protects itself by shutting down, so the error code itself doesn't usually damage it. However, frequent power outages and voltage drops can eventually affect the electronics in the long run.

Where can I see the rest of the codes?

In the error code index Junkers and, for messages that are not faults, in the Cerapur display message.