BoilerFaultCodes 01
Ignition failure: Flame not detected during ignition sequence
Alpha E-Tec 33 Fault codes & diagnostics
32 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Combi Natural Gas 33 kW 2018-present
GC Number 47-532-70
Download the Alpha E-Tec 33 manual
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Note it down before pressing reset — resetting clears the code immediately. How to read fault codes →
Severity at a glance
Each cell = one fault code. Hover to identify. 32 Unrated
Just want the most common Alpha E-Tec 33 faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes
All 32 documented codes
Tap any card for details
02
Overheat boiler lock out: Overheat sensor has activated
03
High flue temperature: Flue sensor intervention (flue temperature too high)
04
Gas valve electrical connection fault: Gas valve wiring circuit fault detected
05
CH flow sensor fault: Incorrect flow sensor resistance value
06
DHW sensor fault: DHW sensor resistance value is incorrect
08
Max. number of resets: Maximum number of resets reached (5)
10
Primary system pressure low: Primary pressure switch has operated
12
DHW inlet sensor fault: Optional DHW inlet sensor resistance out of range
15
Incorrect configuration: Incorrect hydraulic configuration. There is an inconsistency between the settings and signals received from the PCB
Showing 11–20 of 32
16
Fan fault: Fan wiring fault or fan faulty
20
Flame sensing fault: False flame detection. Flame detected but gas valve is not open
22
PCB fault: PCB software error
23
Return sensor fault: Return sensor resistance out of range
24
Control panel button fault: Control panel button stuck in the on position
25
PCB fault: PCB fault - software error
27
Primary circuit overheat: Insufficient circulation in primary circuit causing overheating
29
Flue sensor fault: Flue sensor resistance out of range
31
Loss of communication with external control (Alpha Climatic): Loss of connection between the boiler and Alpha Climatic control unit
37
Low supply voltage: Insufficient supply voltage to operate boiler
Showing 21–30 of 32
38
Loss of flame rectification: Flame detected but signal lost. Ignition retries after fan purge
43
Loss of flame rectification: Repeated loss of flame signal during operation. This fault can occur if the flue is exposed to high wind conditions (shown as E38 in the fault code history in the INFO menu)
45
High )T: The boiler detects a sudden, unexpected increase )T between the flow sensor and the system return sensor
47
Reduced burner output: Flue thermostat has sensed high flue gas temperature (110°C) and reduced the burner output to prevent damage. If the temperature continues to rise the boiler will lock out and E03 will be displayed
51
Climatic RF communication fault: Error between communication of the Climatic transmitter and boiler receiver
60
Pump fault: The pump is stuck or there is an electrical pump fault
61
Air in the pump: Restricted CH flow due to air or a circuit restriction
70
Return/flow sensor error (return reading higher than flow): Possible wiring fault, sensors incorrectly fitted, system blocked
75
Return/flow sensor: Possible failure of one or both sensor
76
Return/flow sensor fault
Showing 31–32 of 32
n
Boiler completely turned off - Screen only shows a single dot to indicate boiler is completely off
Sr
Service reminder count down (0 - 36 months) has reached zero
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