ATAG Boiler Error Codes / Fault Codes - WarmZilla

ATAG may not be a household name in the UK yet, but they’ve been quietly building a reputation for quality and efficiency for over 70 years. Known for engineering excellence and ultra-efficient performance, ATAG boilers have advanced features, including the iCon heat exchanger, which maintains up to 98% of its efficiency throughout the boiler’s life. That means lower energy bills and fewer carbon emissions. Win-win!

But even the best boilers can run into the occasional hiccup. If your ATAG boiler is showing a fault or error code, don’t panic. This guide will help you understand what those codes mean so you can describe the issue clearly to a gas-safe engineer and get things sorted quickly.

Whether you’re considering an ATAG boiler for your home or you already have one and want to know more, you’re in the right place. We’ll discuss common ATAG boiler problems, what makes these boilers stand out, and why they continue to receive top ratings from homeowners and professionals alike.

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Why ATAG Boilers Stand Out:

• Exceptionally quiet operation
• 4 different models to suit various homes
• Up to 14 years warranty for peace of mind
• Trusted in both domestic and commercial settings
• One of the most energy efficient boilers in Europe
• Outstanding 4.7/5 rating on Trustpilot from 4,800+ reviews

Let’s dive into the error codes to help you get your ATAG boiler back in top shape.

ATAG boiler error codes

Fault Code	System Behaviour
10	Outside sensor error
20	Flow sensor error
40	Return sensor error
61	Bus communication error
78	Water pressure out of range
105	Venting program active when power turned on/interrupted (runs for 7 mins)
110	Exceeded safety temperature
111	Exceeded maximum pressure
119	X2 link positions 4 and 5 are missing
129	Fan doesn’t start
133	No flame after 5 ignition attempts
151	Fan error or control unit defective (speed control is not achieved)
154	Return greater than flow – flow temperature increases too fast
101	Overheat error
102	Pressure sensor fault
104	Flow check failed
108	Pressure needs filling
1P4	Pressure needs filling to 0.5 – 0.8 bar
109	Pressure > Pmax error
110	Send probe damaged
112	Return probe error – could be damaged
114	Outdoor sensor error – could be damaged
141	Central heating flow switch is open
201	Domestic hot water (DHW) probe damaged
203	Tank probe damaged
303	Printed circuit board (PCB) error
304	Too many resets have occurred
501	No flame detected
612	Fan fault – fan isn’t starting up

iC & iS Combi Boiler Error Codes

Fault Code	System Behaviour
50	Domestic hot water (DHW) sensor error
117	Pressure greater than 3 bar or pump pressure increase is too high
118	Pressure less than 1 bar or pump pressure increase too low (no pump detection)

ATAG Error code 133

If you are seeing the error code 133, your boiler’s flame is failing after 5 ignition attempts. This could be down to your condensate pipe freezing. A frozen condensate pipe is something that is often easily fixed, you can find out how in this guide to defrosting a condensate pipe.

Other Fault Codes

If you see a spanner symbol this could be one of two things:

Firstly it could mean your boiler is in service mode.

Secondly, it could be blocking, if the boiler is blocking the code is only temporary and will clear itself or will lock the boiler after several attempts if the error keeps on occurring.

If you’ve reached the end of this blog and still feel like you may benefit more from having a new boiler installed, then get a boiler quote from WarmZilla today! You can get a quote for a brand spanking new boiler in just a few minutes.

All you need to do is answer some simple questions online about your current boiler, your home demands, and we will provide you with a list of suitable boilers for your home. We also offer a Best Price Guarantee, ensuring that we will beat any competitors by £50 if you manage to find a boiler cheaper elsewhere (which you won’t ??).

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Boiler Manuals

• Atag premier
• Atag iC 24
• Atag iC 24 LPG
• Atag iC 28
• Atag iC 28 LPG
• Atag iC 36
• Atag iC 36 LPG
• Atag iC 40
• Atag iC 40 LPG
• Atag iC economiser 27
• Atag iC economiser 27 LPG
• Atag iC economoser 35
• Atag iC economiser 35 LPG
• Atag iC economiser 39
• Atag iC economiser 39 LPG
• Atag iR 12
• Atag iR 12 LPG
• Atag iR 15
• Atag iR 15 LPG
• Atag iR 18
• Atag iR 18 LPG
• Atag iR 24
• Atag iR 24 LPG
• Atag iR 32
• Atag iR 32 LPG
• Atag iR 40
• Atag iR 40 LPG
• Atag iS 12
• Atag iS 12 LPG
• Atag iS 15
• Atag iS 15 LPG
• Atag iS 18
• Atag iS 18 LPG
• Atag iS 24
• Atag iS 24 LPG
• Atag iS 32
• Atag iS 32 LPG
• Atag iS 40
• Atag iS 40 LPG
• Atag blauwe engel
• Atag A200S
• Atag A320S
• Atsg A203C
• Atag A325C
• Atag A325X
• Atag A200SOV
• Atag E22s
• Atag E32S
• Atag E22C
• Atag E32C
• Atag Q 25 S
• Atag Q 38 S
• Atag Q 51 S
• Atag Q 60 S
• Atag Q 25 C
• Atag Q 38 C
• Atag Q 51 C
• Atag XL 70
• Atag XL 110
• Atag XL 140
• Atag XL F 75
• Atag XL F 105
• Atag XL F 125
• Atag XL F 150
• Atag XL F 180
• Atag XL F 210
• Atag XL W 75
• Atag XL W 105
• Atag XL W 125
• Atag XL W 150
• Atag XL W 180
• Atag XL W 210