What are the key installation requirements for the Alpha E-Tec 28?

Installation of the Alpha E-Tec 28 requires specific clearances: 450mm at the front, 5mm at the sides, 235mm at the top, and 150mm at the bottom. It must be mounted on a flat vertical wall capable of supporting its weight. The central heating system must be thoroughly cleaned and flushed, with a corrosion inhibitor added, to ensure warranty validity.

What does fault code 01 mean on the Alpha E-Tec 28 (NG)?

Ignition failure Likely causes: Gas supply; Check ignition/sensing electrode; Ignition generator or lead; Gas valve operation; Check PCB and wire connections; Flue restriction or blockage.

What does fault code 02 mean on the Alpha E-Tec 28 (NG)?

Overheat boiler lock out Likely causes: Pump or restricted flow problem; Blocked heat exchanger; Air in heat exchanger; Check external valves/circuit *.

What does fault code 03 mean on the Alpha E-Tec 28 (NG)?

High flue temperature Likely causes: Blocked or restricted primary flow; Heat exchanger air flow blocked; Flue restriction; Flue sensor fault; Air in primary heat exchanger.

What does fault code 04 mean on the Alpha E-Tec 28 (NG)?

Gas valve electrical connection fault Likely causes: Gas valve lead connection fault; Faulty gas valve; Faulty PCB.

What does fault code 05 mean on the Alpha E-Tec 28 (NG)?

CH flow sensor fault Likely causes: Flow sensor wire connections or sensor faulty.

What does fault code 06 mean on the Alpha E-Tec 28 (NG)?

DHW sensor fault Likely causes: DHW sensor wiring connection or sensor faulty.

What does fault code 10 mean on the Alpha E-Tec 28 (NG)?

Primary system pressure low Likely causes: Check expansion vessel pressure (1 bar); Leak in system; Expansion relief valve operated; Primary pressure switch.

What does fault code 12 mean on the Alpha E-Tec 28 (NG)?

DHW inlet sensor fault Likely causes: Check sensor wiring and connections; Check sensor resistance.

What does fault code 15 mean on the Alpha E-Tec 28 (NG)?

Incorrect configuration Likely causes: Check the settings of the 'A' family parameters.

What does fault code 16 mean on the Alpha E-Tec 28 (NG)?

Fan fault Likely causes: Check fan wiring connections; Fan fault; PCB fault.

What does fault code 20 mean on the Alpha E-Tec 28 (NG)?

Flame sensing fault Likely causes: Check flame sensing electrode and lead; Electrical short circuit on sensing wires; PCB fault.

What does fault code 22 mean on the Alpha E-Tec 28 (NG)?

PCB fault Likely causes: Replace PCB. Replace PCB

What does fault code 23 mean on the Alpha E-Tec 28 (NG)?

Return sensor fault Likely causes: Check sensor wiring and connections; Check sensor resistance.

What does fault code 24 mean on the Alpha E-Tec 28 (NG)?

Control panel button fault Likely causes: Check for jammed control panel buttons; Check for jammed PCB buttons.

What does fault code 25 mean on the Alpha E-Tec 28 (NG)?

PCB fault Likely causes: Replace PCB. Replace PCB

What does fault code 27 mean on the Alpha E-Tec 28 (NG)?

Primary circuit overheat Likely causes: Air in heat exchanger; Isolation/system valves closed; Check wiring/power to pump; Pump seized/blocked; Pump failed.

What does fault code 29 mean on the Alpha E-Tec 28 (NG)?

Flue sensor fault Likely causes: Check sensor wiring and connections; Check sensor resistance.

What does fault code 31 mean on the Alpha E-Tec 28 (NG)?

Loss of communication with external control (Alpha Climatic) Likely causes: Remote control or receiver connection wiring; Distance or interference of RF signal; Remote control or receiver fault; (Check batteries if using RF controller).

What does fault code 37 mean on the Alpha E-Tec 28 (NG)?

Low supply voltage Likely causes: Check mains power supply; Check for bad cable connections etc.

What does fault code 38 mean on the Alpha E-Tec 28 (NG)?

Loss of flame rectification Likely causes: Check flame sensing electrode and lead; Check for flue gas recirculation; Check the gas valve; Check flue system and termination; Check gas supply/working pressure; Check/adjust combustion settings; Check burner earth connection.

What does fault code 43 mean on the Alpha E-Tec 28 (NG)?

Loss of flame rectification Likely causes: Check as above for error code 38.

What does fault code 45 mean on the Alpha E-Tec 28 (NG)?

High ΔT Likely causes: Burner input is limited for boiler protection, and once the right ΔT is restored, the boiler resumes regular operation. Make sure there is water circulating in the boiler, that the pump is configured according to the system requirements and that the return sensor is correct..

What does fault code 47 mean on the Alpha E-Tec 28 (NG)?

Reduced burner output Likely causes: Air in heat exchanger; Restricted primary flow; Heat exchanger air flow blocked; Flue restriction; Flue sensor fault; Pump fault.

What does fault code 51 mean on the Alpha E-Tec 28 (NG)?

Climatic RF communication fault Likely causes: Batteries require replacing.

What does fault code 60 mean on the Alpha E-Tec 28 (NG)?

Pump fault Likely causes: Check the pump operation, it may be necessary to free the pump shaft; Check the pump wiring; Replace the pump.

What does fault code 61 mean on the Alpha E-Tec 28 (NG)?

Air in the pump Likely causes: Check Flow and Return valves are open; Check for correct system pressure; Check the system is purged properly.

What does fault code 70 mean on the Alpha E-Tec 28 (NG)?

Return/flow sensor error (return reading higher than flow) Likely causes: Check sensor wiring and connections; Check sensor resistance; Check circulation.

What does fault code 75 mean on the Alpha E-Tec 28 (NG)?

Return/flow sensor fault Likely causes: Check sensor wiring and connections; Check sensor resistance.

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Alpha

E-Tec 28 (NG)

Q: What does fault code 08 mean on the Alpha E-Tec 28 (NG)?

Max. number of resets Likely causes: Refer to fault history codes (INFO menu d9), to reset by turning the boiler off and on. If it will not clear replace PCB. If it will not clear replace PCB

The Alpha E-Tec 28 is a 28.3 kW combi boiler, introduced in 2018, offering 93% seasonal efficiency and an ErP A-rating for heating and hot water.

The Alpha E-Tec 28 is a wall-hung condensing combi boiler designed for domestic heating and hot water provision in UK properties. Introduced in 2018, this model offers a maximum domestic hot water output of 28.3 kW and a central heating output of 24.1 kW. It is available in both natural gas and LPG variants, identified by their respective GC numbers 47 532 69 and 47 532 73. This appliance is suitable for engineers requiring detailed specifications, fault diagnostics, and service information.

CH output: 24.1 kW
DHW flow (∆30°C): 14.1 L/min
ErP rating: A
NOx class: 6

E-Tec 28 (NG) at a glance

Type: combi · natural_gas / lpg
Output: 24.1 kW heating · 28.3 kW hot water
Efficiency: A ErP · 93% seasonal
DHW flow rate: 14.1 L/min @ Δ30°C
Dimensions: 712 × 440 × 268 mm · 33.6 kg
Manufacturer: Alpha
GC number: 47 532 69

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E-Tec 28 (NG) data sheet

Full technical specifications extracted from the manufacturer brochure. Empty sections are hidden.

Identification▼

Model name: E-Tec 28
Model number: E-Tec 28
Manufacturer: Alpha
GC number: 47 532 69
Product family: E-Tec
Year introduced: 2018

Type & fuel▼

Boiler type: Combi
Fuel: Natural gas, LPG
Condensing: Yes
Mounting: Wall-hung

Output▼

CH output (min): 4.3 kW
CH output (max): 24.1 kW
DHW output (max): 28.3 kW
Heat input (net): 24.6 kW
Heat input (gross): 27.3 kW
Modulation range: 4.3-28.3

Domestic hot water▼

Flow rate (∆T 30°C): 14.1 L/min
Flow rate (∆T 35°C): 12.1 L/min
Min. activation flow: 1.5 L/min

Efficiency▼

Seasonal efficiency: 93 %
ErP rating: A
ErP heating: A
ErP DHW: A
ErP DHW profile: XL
NOx class: 6
NOx emissions: 35 mg/kWh

Physical dimensions▼

Height: 712 mm
Width: 440 mm
Depth: 268 mm
Weight (dry): 33.6 kg
Weight (filled): 35.8 kg

Connections▼

Flow pipe: 22 mm
Return pipe: 22 mm
Gas pipe: 22 mm
Cold mains: 15 mm
DHW outlet: 15 mm
Condensate drain: 22 mm
Flue outlet diameter: 60 mm

Bottom connections for flow, return, gas, DHW inlet/outlet, condensate discharge

Gas▼

Natural gas inlet: 20 mbar
LPG inlet: 37 mbar
Max gas rate (NG): 3.05 m³/h
Max gas rate (LPG): 2.24 kg/h
Injector size (NG): 5 mm
Injector size (LPG): 3.8 mm

Water & pressures▼

Max operating pressure: 2.5 bar
Min operating pressure: 0.5 bar
Expansion vessel: 8 L
EV pre-charge: 1 bar
PRV setting: 3 bar

Electrical▼

Voltage: 230 V
Frequency: 50 Hz
Max power: 80 W
Standby power: 2 W
Fuse rating: 3 A
IP rating: IPX5D

Flue▼

Flue types: horizontal, vertical, plume_management
Flue sizes: 60/100 mm
Max horizontal flue: 12 m
Max vertical flue: 14 m

Heat exchanger▼

Primary material: stainless_steel
Secondary type: plate

Pump▼

Pump type: modulating
Speed settings: 9
Available head (m): 7 m

Controls▼

Compatible controls: Alpha Climatic Programmable Modulating Boiler Energy Manager, Alpha Easy-Stat wireless programmable room thermostat, 24hr mechanical heating clock
OpenTherm compatible: Yes
Weather compensation: Yes
Built-in timer: Yes

Safety▼

Safety devices: overheat, flame_failure, PRV, low_water_pressure
Frost protection: Yes
Ignition type: electronic

Sound▼

Sound power (LwA): 52 dB

Installation▼

Clearance (front): 450 mm
Clearance (sides): 5 mm
Clearance (top): 235 mm
Clearance (bottom): 150 mm

It is essential that the central heating system is thoroughly cleaned and flushed before fitting an Alpha E-Tec boiler. Failure to do so will invalidate the warranty. A proprietary cleaner should be used following the product manufacturers' instructions. After installation the system should then be filled and flushed before final filling. A corrosion inhibitor approved by Alpha must be added to ensure that the heating system operates effectively and efficiently, it is important to maintain the correct level of corrosion inhibition at all times. The corrosion inhibitor should be checked annually at the time of the boiler service, and topped up if necessary. A further dose of corrosion inhibitor should be added to the system every five years.

Warranty▼

Registration required: Yes

Compliance▼

CE / UKCA marked: Yes
ErP compliant: Yes
Other certifications: IPX5D

Engineer's overview

The Alpha E-Tec 28 combi boiler provides a maximum central heating output of 24.1 kW and a domestic hot water output of 28.3 kW, delivering a flow rate of 14.1 litres per minute at a 30°C temperature rise. It operates with a seasonal efficiency of 93% and holds an ErP A-rating for both heating and domestic hot water, with an XL hot water profile. The appliance features a stainless steel primary heat exchanger and a modulating pump with 9 speed settings, offering an available head of 7 metres.

Installation requires specific clearances, including 450mm front and 235mm top, and mandates thorough system cleaning and the use of corrosion inhibitor to maintain warranty validity. The E-Tec 28 supports OpenTherm compatible controls and includes integrated frost protection and a built-in timer. Its compact dimensions of 712mm height, 440mm width, and 268mm depth, combined with a dry weight of 33.6 kg, facilitate wall-hung installation in various domestic settings.

E-Tec 28 (NG) fault codes

Every fault code listed in the manufacturer brochure, with likely causes and engineer actions. Each code has a permalink — paste a URL like https://www.boilertag.com/boilers/alpha/e-tec-28-ng#fault-01 to jump straight to the entry.

Complete list of fault codes for this Alpha E-Tec 28 (NG)
Code	Meaning	Details
01	Ignition failure Show causes & actions Flame not detected during ignition sequence Likely causes Gas supply Check ignition/sensing electrode Ignition generator or lead Gas valve operation Check PCB and wire connections Flue restriction or blockage	Details
02Lockout	Overheat boiler lock out Show causes & actions Overheat sensor has activated Likely causes Pump or restricted flow problem Blocked heat exchanger Air in heat exchanger Check external valves/circuit *	Details
03	High flue temperature Show causes & actions Flue sensor intervention (flue temperature too high) Likely causes Blocked or restricted primary flow Heat exchanger air flow blocked Flue restriction Flue sensor fault Air in primary heat exchanger	Details
04	Gas valve electrical connection fault Show causes & actions Gas valve wiring circuit fault detected Likely causes Gas valve lead connection fault Faulty gas valve Faulty PCB	Details
05	CH flow sensor fault Show causes & actions Incorrect flow sensor resistance value Likely causes Flow sensor wire connections or sensor faulty	Details
06	DHW sensor fault Show causes & actions DHW sensor resistance value is incorrect Likely causes DHW sensor wiring connection or sensor faulty	Details
08Lockout	Max. number of resets Show causes & actions Maximum number of resets reached (5) Likely causes Refer to fault history codes (INFO menu d9), to reset by turning the boiler off and on. If it will not clear replace PCB User action Refer to fault history codes (INFO menu d9), to reset by turning the boiler off and on. Engineer action If it will not clear replace PCB Reset procedure turning the boiler off and on	Details
10	Primary system pressure low Show causes & actions Primary pressure switch has operated Likely causes Check expansion vessel pressure (1 bar) Leak in system Expansion relief valve operated Primary pressure switch	Details
12	DHW inlet sensor fault Show causes & actions Optional DHW inlet sensor resistance out of range Likely causes Check sensor wiring and connections Check sensor resistance	Details
15	Incorrect configuration Show causes & actions Incorrect hydraulic configuration There is an inconsistency between the settings and signals received from the PCB Likely causes Check the settings of the 'A' family parameters	Details
16	Fan fault Show causes & actions Fan wiring fault or fan faulty Likely causes Check fan wiring connections Fan fault PCB fault	Details
20	Flame sensing fault Show causes & actions False flame detection Flame detected but gas valve is not open Likely causes Check flame sensing electrode and lead Electrical short circuit on sensing wires PCB fault	Details
22	PCB fault Show causes & actions PCB software error Likely causes Replace PCB Engineer action Replace PCB	Details
23	Return sensor fault Show causes & actions Return sensor resistance out of range Likely causes Check sensor wiring and connections Check sensor resistance	Details
24	Control panel button fault Show causes & actions Control panel button stuck in the on position Likely causes Check for jammed control panel buttons Check for jammed PCB buttons	Details
25	PCB fault Show causes & actions PCB fault - software error Likely causes Replace PCB Engineer action Replace PCB	Details
27	Primary circuit overheat Show causes & actions Insufficient circulation in primary circuit causing overheating Likely causes Air in heat exchanger Isolation/system valves closed Check wiring/power to pump Pump seized/blocked Pump failed	Details
29	Flue sensor fault Show causes & actions Flue sensor resistance out of range Likely causes Check sensor wiring and connections Check sensor resistance	Details
31	Loss of communication with external control (Alpha Climatic) Show causes & actions Loss of connection between the boiler and Alpha Climatic control unit Likely causes Remote control or receiver connection wiring Distance or interference of RF signal Remote control or receiver fault (Check batteries if using RF controller)	Details
37	Low supply voltage Show causes & actions Insufficient supply voltage to operate boiler Likely causes Check mains power supply Check for bad cable connections etc	Details
38	Loss of flame rectification Show causes & actions Flame detected but signal lost. Ignition retries after fan purge Likely causes Check flame sensing electrode and lead Check for flue gas recirculation Check the gas valve Check flue system and termination Check gas supply/working pressure Check/adjust combustion settings Check burner earth connection	Details
43	Loss of flame rectification Show causes & actions 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) Likely causes Check as above for error code 38	Details
45	High ΔT Show causes & actions The boiler detects a sudden, unexpected increase in ΔT between the flow sensor and the system return sensor Likely causes Burner input is limited for boiler protection, and once the right ΔT is restored, the boiler resumes regular operation. Make sure there is water circulating in the boiler, that the pump is configured according to the system requirements and that the return sensor is correct.	Details
47	Reduced burner output Show causes & actions 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 Likely causes Air in heat exchanger Restricted primary flow Heat exchanger air flow blocked Flue restriction Flue sensor fault Pump fault	Details
51	Climatic RF communication fault Show causes & actions Error between communication of the Climatic transmitter and boiler receiver Likely causes Batteries require replacing	Details
60	Pump fault Show causes & actions The pump is stuck or there is an electrical pump fault Likely causes Check the pump operation, it may be necessary to free the pump shaft Check the pump wiring Replace the pump	Details
61	Air in the pump Show causes & actions Restricted CH flow due to air or a circuit restriction Likely causes Check Flow and Return valves are open Check for correct system pressure Check the system is purged properly	Details
70	Return/flow sensor error (return reading higher than flow) Show causes & actions Possible wiring fault, sensors incorrectly fitted, system blocked Likely causes Check sensor wiring and connections Check sensor resistance Check circulation	Details
75	Return/flow sensor fault Show causes & actions Possible failure of one or both sensors Likely causes Check sensor wiring and connections Check sensor resistance	Details
76	Return/flow sensor fault Show causes & actions Possible failure of one or both sensors Likely causes Check sensor wiring and connections Check sensor resistance	Details
Sr	Service reminder Show causes & actions Service reminder count down (0 - 36 months) has reached zero. See Section 6.13, parameter P6. Note: E97 is also shown on Climatic controller, if used User action Note: The 'Sr' code will not stop the boiler functioning Note: Pressing the RESET button will clear the 'Sr' code for 24 hrs to allow the display to be read Engineer action To permanently reset the error 'Sr' / E97 1. Enter the parameter menu using the password 69. See Section 6.13 2. Parameter P6 will show 0 3. Set P6 to any value above zero, save by pressing the mode button (1) and wait for '88' to be displayed as confirmation 4. Then set P6 to 0, save by pressing the mode button (1) and wait for '88' to be displayed as confirmation 5. Now set the parameter P6 at the number of months to the next service reminder (i.e. 12 for one year). Save by pressing the mode button (1) and wait for '88' to be displayed as confirmation	Details
Boiler completely turned off	Boiler completely turned off Show causes & actions Screen only shows a single dot to indicate boiler is completely off User action Press mode button (1) for 2 seconds then release. Boiler display will return and you can select an operating mode	Details
Boiler fused blown	Boiler fused blown Show causes & actions Fuse on main PCB blown Likely causes Incorrect power supply. Seized or sticking pump - Check pump for free rotation Boiler component drawing excessive current. Check individual components in turn	Details

Common E-Tec 28 (NG) problems & troubleshooting

Patterns that group across the manufacturer's fault-code table. Each entry links to the full code listing further down the page.

How to fix the E-Tec 28 (NG) overheat boiler lock outLockout

Triggered by fault code 02.

How to fix the E-Tec 28 (NG) max. number of resetsLockout

User: Refer to fault history codes (INFO menu d9), to reset by turning the boiler off and on.

Engineer: If it will not clear replace PCB

Triggered by fault code 08.

How to fix the E-Tec 28 (NG) ignition failure

Triggered by fault code 01.

How to fix the E-Tec 28 (NG) high flue temperature

Triggered by fault code 03.

How to fix the E-Tec 28 (NG) gas valve electrical connection fault

Triggered by fault code 04.

Likely causes that trigger multiple E-Tec 28 (NG) fault codes

Check sensor resistance: Fault codes: 12, 23, 29, 70, 75, 76
Check sensor wiring and connections: Fault codes: 12, 23, 29, 70, 75, 76
Air in heat exchanger: Fault codes: 02, 27, 47
Check flame sensing electrode and lead: Fault codes: 20, 38
Flue restriction: Fault codes: 03, 47
Flue sensor fault: Fault codes: 03, 47
Heat exchanger air flow blocked: Fault codes: 03, 47
Pcb fault: Fault codes: 16, 20
Replace pcb: Fault codes: 22, 25
(check batteries if using rf controller): Fault codes: 31
Air in primary heat exchanger: Fault codes: 03
Batteries require replacing: Fault codes: 51

E-Tec 28 (NG) FAQs

Common questions from engineers and homeowners about the Alpha E-Tec 28 (NG).

What are the key installation requirements for the Alpha E-Tec 28?: Installation of the Alpha E-Tec 28 requires specific clearances: 450mm at the front, 5mm at the sides, 235mm at the top, and 150mm at the bottom. It must be mounted on a flat vertical wall capable of supporting its weight. The central heating system must be thoroughly cleaned and flushed, with a corrosion inhibitor added, to ensure warranty validity.

Common service parts

Parts referenced in the manufacturer brochure for routine service and repair.

Diverter cartridge
3.025230
Pressure gauge
1.034600
Condensate trap
1.039244
Bottom condensate trap connection
1.023581
Flow/Return sensor
1.039476
DHW temperature sensor
1.039477
Electrode
1.039673
Electrode gasket
1.030251
Flue turret with seals
3.027702
DHW flow switch
1.035365
Pump head motor
1.038162
Primary heat exchanger assembly - 28
3.027697
Primary heat exchanger assembly - 33
3.027698
Burner - 28
1.040669
Burner - 33
1.040670
Burner gasket
1.025910
Diverter valve motor
1.033918
Pressure switch
1.027277
DHW heat exchanger - 28 with seals
3.022783
DHW heat exchanger - 33 with seals
3.021693
Main PCB
1.037031
Safety valve 3 bar
1.028561
Gas valve
1.039944
Automatic air vent with 'O'-ring seal
1.027110
Relief valve to condensate connecting pipe
1.037890
Expansion vessel
1.039208
Fan
3.027699
Flue sampling point cap
3.026794
Complete boiler seal kit
3.027771
Hydraulic circuit seal kit
3.025323
Complete heat exchanger seal kit
3.027772
Gas pipe to fan manifold
1.039140
Gas pipe 'O' ring
1.037816
Clip - Flow/return pipe to heat exchanger
1.026763
Clip - Gas pipe connections
1.020393
Boiler wall bracket
2.015350
Boiler connection kit
3.024893
Boiler accessory box complete
3.026880
Wall template
1.039776
Burner front insulation panel
1.039141
Flue sensor
1.024296
Rear combustion insulation panel
1.040351

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Specifications on this page are extracted from the manufacturer brochure. Always cross-check against the latest datasheet before commissioning or quoting. Last updated 28 June 2026.

← Browse all Alpha boilers

Alpha

E-Tec 28 (NG)

The Alpha E-Tec 28 is a 28.3 kW combi boiler, introduced in 2018, offering 93% seasonal efficiency and an ErP A-rating for heating and hot water.

CH output: 24.1 kW
DHW flow (∆30°C): 14.1 L/min
ErP rating: A
NOx class: 6

E-Tec 28 (NG) at a glance

Type: combi · natural_gas / lpg
Output: 24.1 kW heating · 28.3 kW hot water
Efficiency: A ErP · 93% seasonal
DHW flow rate: 14.1 L/min @ Δ30°C
Dimensions: 712 × 440 × 268 mm · 33.6 kg
Manufacturer: Alpha
GC number: 47 532 69

Register this Alpha E-Tec 28 (NG) on BoilerTag

Stick a QR tag on the case, scan it on every service and give your customer a permanent, shareable service history they can pull up from any phone.

Permanent, shareable service history
One QR scan on the boiler surfaces every previous fault, part change and visit — no paperwork to dig out.
Free AI fault diagnostics, built in
Every tag you fit unlocks the AI diagnostic tool for that exact model — paste a fault code, get a ranked cause list.
Your name on the boiler forever
When the next service or breakdown comes around the homeowner scans and sees your number first.
First 12 BoilerTags are free
Tag every install and service you do from now on — the subscription only kicks in once you scale past your first dozen.

Diagnosing a fault on a Alpha E-Tec 28 (NG) right now?

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Open the diagnostics tool →

E-Tec 28 (NG) data sheet

Full technical specifications extracted from the manufacturer brochure. Empty sections are hidden.

Identification▼

Model name: E-Tec 28
Model number: E-Tec 28
Manufacturer: Alpha
GC number: 47 532 69
Product family: E-Tec
Year introduced: 2018

Type & fuel▼

Boiler type: Combi
Fuel: Natural gas, LPG
Condensing: Yes
Mounting: Wall-hung

Output▼

CH output (min): 4.3 kW
CH output (max): 24.1 kW
DHW output (max): 28.3 kW
Heat input (net): 24.6 kW
Heat input (gross): 27.3 kW
Modulation range: 4.3-28.3

Domestic hot water▼

Flow rate (∆T 30°C): 14.1 L/min
Flow rate (∆T 35°C): 12.1 L/min
Min. activation flow: 1.5 L/min

Efficiency▼

Seasonal efficiency: 93 %
ErP rating: A
ErP heating: A
ErP DHW: A
ErP DHW profile: XL
NOx class: 6
NOx emissions: 35 mg/kWh

Physical dimensions▼

Height: 712 mm
Width: 440 mm
Depth: 268 mm
Weight (dry): 33.6 kg
Weight (filled): 35.8 kg

Connections▼

Flow pipe: 22 mm
Return pipe: 22 mm
Gas pipe: 22 mm
Cold mains: 15 mm
DHW outlet: 15 mm
Condensate drain: 22 mm
Flue outlet diameter: 60 mm

Bottom connections for flow, return, gas, DHW inlet/outlet, condensate discharge

Gas▼

Natural gas inlet: 20 mbar
LPG inlet: 37 mbar
Max gas rate (NG): 3.05 m³/h
Max gas rate (LPG): 2.24 kg/h
Injector size (NG): 5 mm
Injector size (LPG): 3.8 mm

Water & pressures▼

Max operating pressure: 2.5 bar
Min operating pressure: 0.5 bar
Expansion vessel: 8 L
EV pre-charge: 1 bar
PRV setting: 3 bar

Electrical▼

Voltage: 230 V
Frequency: 50 Hz
Max power: 80 W
Standby power: 2 W
Fuse rating: 3 A
IP rating: IPX5D

Flue▼

Flue types: horizontal, vertical, plume_management
Flue sizes: 60/100 mm
Max horizontal flue: 12 m
Max vertical flue: 14 m

Heat exchanger▼

Primary material: stainless_steel
Secondary type: plate

Pump▼

Pump type: modulating
Speed settings: 9
Available head (m): 7 m

Controls▼

Compatible controls: Alpha Climatic Programmable Modulating Boiler Energy Manager, Alpha Easy-Stat wireless programmable room thermostat, 24hr mechanical heating clock
OpenTherm compatible: Yes
Weather compensation: Yes
Built-in timer: Yes

Safety▼

Safety devices: overheat, flame_failure, PRV, low_water_pressure
Frost protection: Yes
Ignition type: electronic

Sound▼

Sound power (LwA): 52 dB

Installation▼

Clearance (front): 450 mm
Clearance (sides): 5 mm
Clearance (top): 235 mm
Clearance (bottom): 150 mm

Warranty▼

Registration required: Yes

Compliance▼

CE / UKCA marked: Yes
ErP compliant: Yes
Other certifications: IPX5D

Engineer's overview

E-Tec 28 (NG) fault codes

Complete list of fault codes for this Alpha E-Tec 28 (NG)
Code	Meaning	Details
01	Ignition failure Show causes & actions Flame not detected during ignition sequence Likely causes Gas supply Check ignition/sensing electrode Ignition generator or lead Gas valve operation Check PCB and wire connections Flue restriction or blockage	Details
02Lockout	Overheat boiler lock out Show causes & actions Overheat sensor has activated Likely causes Pump or restricted flow problem Blocked heat exchanger Air in heat exchanger Check external valves/circuit *	Details
03	High flue temperature Show causes & actions Flue sensor intervention (flue temperature too high) Likely causes Blocked or restricted primary flow Heat exchanger air flow blocked Flue restriction Flue sensor fault Air in primary heat exchanger	Details
04	Gas valve electrical connection fault Show causes & actions Gas valve wiring circuit fault detected Likely causes Gas valve lead connection fault Faulty gas valve Faulty PCB	Details
05	CH flow sensor fault Show causes & actions Incorrect flow sensor resistance value Likely causes Flow sensor wire connections or sensor faulty	Details
06	DHW sensor fault Show causes & actions DHW sensor resistance value is incorrect Likely causes DHW sensor wiring connection or sensor faulty	Details
08Lockout	Max. number of resets Show causes & actions Maximum number of resets reached (5) Likely causes Refer to fault history codes (INFO menu d9), to reset by turning the boiler off and on. If it will not clear replace PCB User action Refer to fault history codes (INFO menu d9), to reset by turning the boiler off and on. Engineer action If it will not clear replace PCB Reset procedure turning the boiler off and on	Details
10	Primary system pressure low Show causes & actions Primary pressure switch has operated Likely causes Check expansion vessel pressure (1 bar) Leak in system Expansion relief valve operated Primary pressure switch	Details
12	DHW inlet sensor fault Show causes & actions Optional DHW inlet sensor resistance out of range Likely causes Check sensor wiring and connections Check sensor resistance	Details
15	Incorrect configuration Show causes & actions Incorrect hydraulic configuration There is an inconsistency between the settings and signals received from the PCB Likely causes Check the settings of the 'A' family parameters	Details
16	Fan fault Show causes & actions Fan wiring fault or fan faulty Likely causes Check fan wiring connections Fan fault PCB fault	Details
20	Flame sensing fault Show causes & actions False flame detection Flame detected but gas valve is not open Likely causes Check flame sensing electrode and lead Electrical short circuit on sensing wires PCB fault	Details
22	PCB fault Show causes & actions PCB software error Likely causes Replace PCB Engineer action Replace PCB	Details
23	Return sensor fault Show causes & actions Return sensor resistance out of range Likely causes Check sensor wiring and connections Check sensor resistance	Details
24	Control panel button fault Show causes & actions Control panel button stuck in the on position Likely causes Check for jammed control panel buttons Check for jammed PCB buttons	Details
25	PCB fault Show causes & actions PCB fault - software error Likely causes Replace PCB Engineer action Replace PCB	Details
27	Primary circuit overheat Show causes & actions Insufficient circulation in primary circuit causing overheating Likely causes Air in heat exchanger Isolation/system valves closed Check wiring/power to pump Pump seized/blocked Pump failed	Details
29	Flue sensor fault Show causes & actions Flue sensor resistance out of range Likely causes Check sensor wiring and connections Check sensor resistance	Details
31	Loss of communication with external control (Alpha Climatic) Show causes & actions Loss of connection between the boiler and Alpha Climatic control unit Likely causes Remote control or receiver connection wiring Distance or interference of RF signal Remote control or receiver fault (Check batteries if using RF controller)	Details
37	Low supply voltage Show causes & actions Insufficient supply voltage to operate boiler Likely causes Check mains power supply Check for bad cable connections etc	Details
38	Loss of flame rectification Show causes & actions Flame detected but signal lost. Ignition retries after fan purge Likely causes Check flame sensing electrode and lead Check for flue gas recirculation Check the gas valve Check flue system and termination Check gas supply/working pressure Check/adjust combustion settings Check burner earth connection	Details
43	Loss of flame rectification Show causes & actions 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) Likely causes Check as above for error code 38	Details
45	High ΔT Show causes & actions The boiler detects a sudden, unexpected increase in ΔT between the flow sensor and the system return sensor Likely causes Burner input is limited for boiler protection, and once the right ΔT is restored, the boiler resumes regular operation. Make sure there is water circulating in the boiler, that the pump is configured according to the system requirements and that the return sensor is correct.	Details
47	Reduced burner output Show causes & actions 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 Likely causes Air in heat exchanger Restricted primary flow Heat exchanger air flow blocked Flue restriction Flue sensor fault Pump fault	Details
51	Climatic RF communication fault Show causes & actions Error between communication of the Climatic transmitter and boiler receiver Likely causes Batteries require replacing	Details
60	Pump fault Show causes & actions The pump is stuck or there is an electrical pump fault Likely causes Check the pump operation, it may be necessary to free the pump shaft Check the pump wiring Replace the pump	Details
61	Air in the pump Show causes & actions Restricted CH flow due to air or a circuit restriction Likely causes Check Flow and Return valves are open Check for correct system pressure Check the system is purged properly	Details
70	Return/flow sensor error (return reading higher than flow) Show causes & actions Possible wiring fault, sensors incorrectly fitted, system blocked Likely causes Check sensor wiring and connections Check sensor resistance Check circulation	Details
75	Return/flow sensor fault Show causes & actions Possible failure of one or both sensors Likely causes Check sensor wiring and connections Check sensor resistance	Details
76	Return/flow sensor fault Show causes & actions Possible failure of one or both sensors Likely causes Check sensor wiring and connections Check sensor resistance	Details
Sr	Service reminder Show causes & actions Service reminder count down (0 - 36 months) has reached zero. See Section 6.13, parameter P6. Note: E97 is also shown on Climatic controller, if used User action Note: The 'Sr' code will not stop the boiler functioning Note: Pressing the RESET button will clear the 'Sr' code for 24 hrs to allow the display to be read Engineer action To permanently reset the error 'Sr' / E97 1. Enter the parameter menu using the password 69. See Section 6.13 2. Parameter P6 will show 0 3. Set P6 to any value above zero, save by pressing the mode button (1) and wait for '88' to be displayed as confirmation 4. Then set P6 to 0, save by pressing the mode button (1) and wait for '88' to be displayed as confirmation 5. Now set the parameter P6 at the number of months to the next service reminder (i.e. 12 for one year). Save by pressing the mode button (1) and wait for '88' to be displayed as confirmation	Details
Boiler completely turned off	Boiler completely turned off Show causes & actions Screen only shows a single dot to indicate boiler is completely off User action Press mode button (1) for 2 seconds then release. Boiler display will return and you can select an operating mode	Details
Boiler fused blown	Boiler fused blown Show causes & actions Fuse on main PCB blown Likely causes Incorrect power supply. Seized or sticking pump - Check pump for free rotation Boiler component drawing excessive current. Check individual components in turn	Details

Common E-Tec 28 (NG) problems & troubleshooting

Patterns that group across the manufacturer's fault-code table. Each entry links to the full code listing further down the page.

How to fix the E-Tec 28 (NG) overheat boiler lock outLockout

Triggered by fault code 02.

How to fix the E-Tec 28 (NG) max. number of resetsLockout

User: Refer to fault history codes (INFO menu d9), to reset by turning the boiler off and on.

Engineer: If it will not clear replace PCB

Triggered by fault code 08.

How to fix the E-Tec 28 (NG) ignition failure

Triggered by fault code 01.

How to fix the E-Tec 28 (NG) high flue temperature

Triggered by fault code 03.

How to fix the E-Tec 28 (NG) gas valve electrical connection fault

Triggered by fault code 04.

Likely causes that trigger multiple E-Tec 28 (NG) fault codes

Check sensor resistance: Fault codes: 12, 23, 29, 70, 75, 76
Check sensor wiring and connections: Fault codes: 12, 23, 29, 70, 75, 76
Air in heat exchanger: Fault codes: 02, 27, 47
Check flame sensing electrode and lead: Fault codes: 20, 38
Flue restriction: Fault codes: 03, 47
Flue sensor fault: Fault codes: 03, 47
Heat exchanger air flow blocked: Fault codes: 03, 47
Pcb fault: Fault codes: 16, 20
Replace pcb: Fault codes: 22, 25
(check batteries if using rf controller): Fault codes: 31
Air in primary heat exchanger: Fault codes: 03
Batteries require replacing: Fault codes: 51

E-Tec 28 (NG) FAQs

Common questions from engineers and homeowners about the Alpha E-Tec 28 (NG).

What are the key installation requirements for the Alpha E-Tec 28?: Installation of the Alpha E-Tec 28 requires specific clearances: 450mm at the front, 5mm at the sides, 235mm at the top, and 150mm at the bottom. It must be mounted on a flat vertical wall capable of supporting its weight. The central heating system must be thoroughly cleaned and flushed, with a corrosion inhibitor added, to ensure warranty validity.

Common service parts

Parts referenced in the manufacturer brochure for routine service and repair.

Diverter cartridge
3.025230
Pressure gauge
1.034600
Condensate trap
1.039244
Bottom condensate trap connection
1.023581
Flow/Return sensor
1.039476
DHW temperature sensor
1.039477
Electrode
1.039673
Electrode gasket
1.030251
Flue turret with seals
3.027702
DHW flow switch
1.035365
Pump head motor
1.038162
Primary heat exchanger assembly - 28
3.027697
Primary heat exchanger assembly - 33
3.027698
Burner - 28
1.040669
Burner - 33
1.040670
Burner gasket
1.025910
Diverter valve motor
1.033918
Pressure switch
1.027277
DHW heat exchanger - 28 with seals
3.022783
DHW heat exchanger - 33 with seals
3.021693
Main PCB
1.037031
Safety valve 3 bar
1.028561
Gas valve
1.039944
Automatic air vent with 'O'-ring seal
1.027110
Relief valve to condensate connecting pipe
1.037890
Expansion vessel
1.039208
Fan
3.027699
Flue sampling point cap
3.026794
Complete boiler seal kit
3.027771
Hydraulic circuit seal kit
3.025323
Complete heat exchanger seal kit
3.027772
Gas pipe to fan manifold
1.039140
Gas pipe 'O' ring
1.037816
Clip - Flow/return pipe to heat exchanger
1.026763
Clip - Gas pipe connections
1.020393
Boiler wall bracket
2.015350
Boiler connection kit
3.024893
Boiler accessory box complete
3.026880
Wall template
1.039776
Burner front insulation panel
1.039141
Flue sensor
1.024296
Rear combustion insulation panel
1.040351

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Specifications on this page are extracted from the manufacturer brochure. Always cross-check against the latest datasheet before commissioning or quoting. Last updated 28 June 2026.

E-Tec 28 (NG) at a glance

Register this Alpha E-Tec 28 (NG) on BoilerTag

E-Tec 28 (NG) data sheet

Engineer's overview

E-Tec 28 (NG) fault codes

Common E-Tec 28 (NG) problems & troubleshooting

How to fix the E-Tec 28 (NG) overheat boiler lock outLockout

How to fix the E-Tec 28 (NG) max. number of resetsLockout

How to fix the E-Tec 28 (NG) ignition failure

How to fix the E-Tec 28 (NG) high flue temperature

How to fix the E-Tec 28 (NG) gas valve electrical connection fault

Likely causes that trigger multiple E-Tec 28 (NG) fault codes

E-Tec 28 (NG) FAQs

Common service parts

Every boiler brochure, free with BoilerTag

Other Alpha boilers

Working on a Alpha E-Tec 28 (NG)?

E-Tec 28 (NG) at a glance

Register this Alpha E-Tec 28 (NG) on BoilerTag

E-Tec 28 (NG) data sheet

Engineer's overview

E-Tec 28 (NG) fault codes

Common E-Tec 28 (NG) problems & troubleshooting

How to fix the E-Tec 28 (NG) overheat boiler lock outLockout

How to fix the E-Tec 28 (NG) max. number of resetsLockout

How to fix the E-Tec 28 (NG) ignition failure

How to fix the E-Tec 28 (NG) high flue temperature

How to fix the E-Tec 28 (NG) gas valve electrical connection fault

Likely causes that trigger multiple E-Tec 28 (NG) fault codes

E-Tec 28 (NG) FAQs

Common service parts

Every boiler brochure, free with BoilerTag

Other Alpha boilers

Working on a Alpha E-Tec 28 (NG)?