Daikin 00 status codewhat it means
Not a fault. Daikin publish 00 as NORMAL, and it is also what shows while you are stepping through the diagnostic.
Before you start
What 00 means
This page exists because 00 gets searched, and the answer is that nothing is wrong. Daikin print it at the top of their code table under the SYSTEM heading with the meaning NORMAL. It is the system telling you it has nothing to report. There are two ways you end up looking at it. The first is that you started the diagnostic procedure: holding Cancel for five seconds produces a blinking 00 in the temperature display, and that is the starting position before you begin stepping through codes. So 00 is what you see before the diagnostic has told you anything, not a result.
The second is that you ran the procedure through and 00 is genuinely what the unit reports, which means the fault you are chasing is not one the system has recorded. That second case is more useful than it sounds, because it narrows things down considerably. A system with a real internal fault will usually have logged one. If the machine is misbehaving and reports 00, look at the things the machine cannot detect: the mode it is set to, the setpoint, whether the filters are blocked, whether the outdoor unit is smothered or its isolator has been switched off, whether the room is simply larger or hotter than the unit was sized for.
None of those produce a code, and all of them produce complaints. It is worth knowing how the beeps work while you are in there, because they are the actual interface and people miss them. Daikin publish that a short beep and two consecutive beeps indicate non-corresponding codes, while a long continuous beep marks the code that applies. So you are listening rather than watching, and pressing on past a double beep is correct behaviour. The display also cancels itself if no button is pressed for a minute, which catches people out midway through.
What causes it
| Cause | What is actually happening | How likely |
|---|---|---|
| The system has no recorded fault | The straightforward reading. Daikin publish 00 as NORMAL, so the unit is telling you it has nothing logged. | Common |
| You are at the start of the diagnostic | Holding Cancel for five seconds produces a blinking 00 before you begin stepping through. That is the starting position rather than a result. | Common |
| A problem the system cannot detect | Mode, setpoint, blocked filters, a smothered outdoor unit or an undersized system all produce complaints and no code, because none of them is a fault the machine can see. | Common |
| The log was cleared | A fault that has been reset or cleared leaves nothing behind. If the problem is intermittent, catch the code while it is happening rather than after a power cycle. | Occasional |
What to try yourself
Confirm you completed the procedure rather than stopping at the start. The blinking 00 that appears when you first hold Cancel is the starting point, not the answer.
Press Cancel repeatedly and listen. A short beep or two consecutive beeps mean the code shown does not apply; keep going until you get a long continuous beep or return to the start.
If it genuinely reports 00, stop looking for a code and start looking at the things the system cannot detect — beginning with the indoor filters.
Check the mode and setpoint on the remote. A unit in fan mode or set above room temperature will run all day and cool nothing, and it is not a fault.
Go outside and check the outdoor unit has clear airflow — Daikin’s own poor-cooling checklist asks whether anything is blocking the air inlet or outlet of the indoor and outdoor units, along with the filters, the setpoint, open windows and the airflow setting.
If the fault is intermittent, run the diagnostic while it is happening. A code retrieved after a power cycle may well have gone.
Get an F-Gas certified heat pump engineer to look at your Daikin 00
We do not pass enquiries to a repair firm, so there is no form here. When you book an F-Gas certified heat pump engineer, tell them the make, the model and the exact code or message on the display, and ask whether they carry parts for this make — that is what turns one visit into a repair rather than a quote.
What it costs to fix
Typical repair cost
£0
Time on site
15 minutes
Nothing. There is no fault here to fix, and if the machine is misbehaving the cause is somewhere the code table does not reach.
Typical UK prices including parts and labour, updated September 2026. Your quote may differ.
Own this appliance and had this code? . Nothing is published until a person has read it.
Related Daikin fault codes
- U0Get it checkedRefrigerant shortage. The circuit is sealed, so if it is short it has leaked — and this is certified work by law, not a top-up.Related: same brand
- A5Get it checkedFreeze-up protection or high pressure control. A filthy indoor filter is a legitimate published cause, which makes this the one on the list worth checking yourself.Related: same brand
- U4Get it checkedThe indoor and outdoor units have stopped talking. Daikin’s own cause list starts with the mains supply and the inter-unit cable, so one breaker cycle is worth a try before anyone is called.Related: same brand
- E6Get it checkedThe compressor failed to start. It sits in Daikin’s outdoor unit group alongside the overload and pressure codes, and all of them are certified work.Related: same brand
Own a Daikin air conditioner? Save it and its codes come first next time.
Related guides
Common questions about Daikin 00
My unit is definitely not working but it says 00.
Then the problem is something the system cannot detect, which is genuinely useful information. Filters, mode, setpoint, airflow at the outdoor unit and sizing all produce poor performance without producing a code. Start with the filters, because they cause more of this than anything else and they cost nothing to check.
How do I know when I have reached the right code?
By the beep. Daikin publish that a short beep and two consecutive beeps indicate non-corresponding codes and that a long continuous beep marks the one that applies. If you are watching the display rather than listening, you will step straight past your own code.
The display disappeared while I was doing it.
That is the timeout. Daikin publish that the code display cancels itself if no button is pressed for one minute. Start again and keep pressing at a steady pace rather than pausing to look codes up as you go.
Should I clear the code once I have read it?
Write it down first, and there is rarely a reason to hurry. The code is the most useful thing you can hand an engineer, and clearing it before anyone has seen it means the diagnosis starts from scratch. Holding Cancel for five seconds exits the display.
Technical review
Not reviewed by an engineer
No engineer has read this page. Severity follows what the manufacturer publishes, and we would rather tell you that than let a byline imply a sign-off.
Sources and how we verified this
We establish the facts from the sources below and then write the explanation ourselves. We do not copy manufacturer wording and we do not host their manuals.
- Manufacturer technical and service documentation
This page has not been reviewed by an engineer, and we would rather tell you that than imply otherwise. The severity rating follows what the manufacturer publishes: where they say isolate the appliance and call someone, so do we.