Atag Fault Codes

Welcome to the fault-codes section of this site. The following table or page contains the information required to help repair and diagnose the fault codes being shown on the boiler display. You may be guided through the fault finding sequence or steps, for rectifying your boiler with this fault code. Suggested repair solutions may be provided by a link to a repair page. NB Some fault codes are only applicable to a specific range of boilers only.

Code	Repair	Meaning	Models
10	Link	Outside sensor error
20	Link	Flow sensor error
40	Link	Return sensor error
50	Link	Domestic hot water (DHW) sensor error	IC, IS
61	Link	Bus communication error
78	Link	Water pressure out of range
105	Link	Venting program active when power turned on / interrupted (runs for 7 mins)Ê
110	Link	Exceeded safety temperature
111	Link	Exceeded maximum pressure
119	Link	X2 link position 4 and 5 missing
129	Link	Fan doesnÕt start
133	Link	No flame after 5 ignition attempts
151	Link	Fan error or control unit defective (speed control is not achieved)Ê
154	Link	Return greater than flow Ð flow temperature increases too fast
101	Link	Overheat error
102	Link	Pressure sensor fault
104	Link	Flow check failed
108	Link	Pressure needs filling to < 0.5 bar
1P4	Link	Pressure needs filling to 0.5 Ð 0.8 bar
109	Link	Pressure > Pmax error
110	Link	Send probe damaged
112	Link	Return probe error Ð could be damanged
114	Link	Outdoor sensor error Ð could be damaged
117	Link	Pressure greater than 3 bar or pump pressure increase is too high	IC, IS
118	Link	Pressure less than 1 bar or pump pressure increase too low (no pump detection).	IC, IS
133	Link	No flame after 5ÊignitionÊattempts
141	Link	Central heating flow switch is open
201	Link	Domestic hot water (DHW) probe damaged
203	Link	Tank probe damaged
303	Link	Printed circuit board (PCB) error
304	Link	Too many resets have occured
501	Link	No flame detected
612	Link	Fan fault Ð fan isnÕt starting up