Daikin Boiler Error Codes, Causes & How To Fix

James Elston
Written by James Elston
Updated on 21st September 2023
Posted on 20th September 2023
Daikin Boiler Error Codes, Causes & How To Fix

Daikin boiler error codes and faults – What they mean & how to fix

daikin boiler error codes

Boiler error codes are the shorthand way of quickly working out what’s causing your heating system problems. While all manufacturers use error codes, what each one is, and its meaning varies from model to model.

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So, whether that means that while Daikin Altherma problems are similar to those from, say, Worcester Bosch or Alpha, the error code will be different.

If you have boiler cover in place already then, a quick call to the customer service centre will have someone heading out to see what’s going on. If you don’t have cover and your boiler is out of warranty, things can, unfortunately, get pricey.

Do though check through our guide on the different errors as with some you might be able to fix the fault yourself and have everything working again in no time at all.

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Common Daikin Boiler Error Codes & Faults

daikin boiler error codes

Some boiler problems occur more often than others. So, we’re going to focus on the most common Daikin error codes first, and then if you can’t see what you’re looking for, you’ll be able to find the code within our comprehensive list at the end of this article.

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How to fix an u4 error code

Two different issues can cause the Daikin U4 fault. First of all, there’s U4-65 which comes up when there are problems with the connection with the room thermostat. Then there’s U4-66 which relates to a timeout on the CAN-bus.

For both of these, it’s worth trying a reset of your boiler to see if that clears the fault.  If you’re not sure how to do that, take a look at your manual for instructions. To download a copy of the manual from Daikin – click here and then select your boiler model.

How to fix an 8a fault code

If the outside temperature has plummeted, then you might see the Daikin error code 8a appear. That’s because it tells you that the boiler has gone into freeze protection mode. This is triggered when the flow temperature sensor shows a value of less than 1°c.

daikin boiler error codes

Prevention is better than cure for this one by avoiding the boiler being turned off in cold conditions or by switching on frost protection mode. It is possible that your Daikin thermostat isn’t working as it should, or there’s a faulty sensor causing an incorrect reading.

So, if the temperature is above freezing, you might be able to try a reset to see if that gets everything working again.

We also have a complete guide on the temperature your thermostat should be set at, which might also be a helpful read.

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All Daikin Boiler Error Codes

Daikin Error CodeFault
10-64Faulty gas valve circuit error
10-65Faulty gas valve current error
11-64Error within ignition
11-65An error within flame stabilisation
11-66Loss of flame signal
11-67Flame loss during operation
12-64Deviation of ion control too great
12-65An error within ignition scott actuators
12-66Ion base value lower than the minimum limit
12-67Ion base value exceeds the maximum limit
12-68Ion base value different from previous
12-69Offset adaptation reached the limit
13-64 / 13-65Error with fan speed
16-64Overheating of flue temperature signals
1J-64Overheating of high limit thermostat
80-01An error within the temperature sensor
81-01Error with flow temperature sensor
81-65Faulty hot water temperature sensor
8A-46Freeze protection mode
8H-65A steep rise within flow temperature
E1-64Detection of flame before burner operates
E1-65An error of internal SCOT system
E1-66Error in calibration condition
E1-67Calibration missing
E1-68Ion base value exceeds the maximum limit
E1-69 / E1-70Fault with parameter CRC
E1-71Failure of EK lockout 
E1-72SCOT flame amplifier
E1-73An error within the printed circuit board
H9-01Fault with outside sensor
HC-01Faulty hot water temperature sensor
HJ-08System pressure too high
HJ-09System pressure too low
HJ-10Fault with water pressure sensor
J6-01Overheating of flow temperature sensor
J6-20Overheating return temperature sensor
J6-21Higher return temperature than flow temperature.
JJ-64Supply voltage below the low limit 
U2-01Supply voltage above the high limit
U4-65Defective openTherm room thermostat
U4-66Timeout of CAN-bus
U4-67Remote reset supervision,
UA-64Boiler chip card (BBC) blocked
UA-65Updated needed for printed circuit board
UA-66An issue with boiler chip card ID
UA-67Missing boiler chip card

Daikin error and faults codes summary

A faulty boiler can be a complete nightmare so getting it working again is always a priority. Daikin fault codes are the first step in establishing what the problem is and helping you to decide if you can resolve the issue yourself or if you’ll need to call out an engineer. Be careful to make sure repairs aren’t more than what a new boiler cost.

If your looking at budget boilers and wanting to consider the issues that they may have, check out these other low cost boielrs that may be of interest and the issues that they have. here are the latest Keston error codes & Navien Error codes for you to browse.

All boilers do have a working lifespan. So, if you find that you have to call out the engineer, again and again, you might have got to the point where a replacement boiler is the best option. No more worries about whether the heating will work or if the children can have a hot bath!  We know though, that there so many different options that it can seem challenging to know where to begin.

This is where our fixed price quotation service comes in. Simply enter your requirements, and we’ll provide personalised boiler deals on some of the best combi boilers and system boilers. Suddenly a new boiler seems much more straightforward!

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Written by
James Elston
James Elston Director Of Boiler Central
Posted on: 20th September 2023

James Elston is our resident boiler replacement and heating expert here at Boiler Central. With over 20 years experience in the boiler installation industry, James ensures that he knows everything there is about our Gas Safe boiler installations, energy saving and home heating solutions. This can be from simply procuring the latest best combi boilers, to reviewing and ensuring that Boiler Central maintains the highest standards across our boiler installation company.

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