How do I register an Alpha E-Tec Plus 28 with BoilerTag?

To register an Alpha E-Tec Plus 28, scan the QR code on the BoilerTag sticker after installation. The system will pre-fill model details from the appliance catalogue. Record the installation date and your Gas Safe number. Every future service log becomes a permanent, publicly viewable record. The first 12 BoilerTag stickers are free for engineers. Order free BoilerTag stickers from the engineer dashboard.

What is the Alpha E-Tec Plus 28?

The Alpha E-Tec Plus 28 is a 28 kW natural gas or LPG combi boiler with an ErP A-rating for heating and hot water, introduced in 2018. It is a wall-hung condensing appliance suitable for domestic installations requiring both central heating and instantaneous hot water.

What are the required clearances for installing an Alpha E-Tec Plus 28?

Installation requires specific clearances: 235 mm at the top for horizontal flues (150 mm for vertical), 150 mm at the bottom, 5 mm on each side, and 450 mm at the front. Do not store articles or combustible materials on or near the boiler or flue pipe.

What should I know about the flue terminal of the Alpha E-Tec Plus 28?

The external flue terminal must not be obstructed. If damaged, turn off the boiler and contact a Service Engineer. As a high-efficiency condensing boiler, the Alpha E-Tec Plus will emit vapour from the terminal, which is normal and safe during operation.

Is annual servicing required for the Alpha E-Tec Plus 28?

Yes, routine annual servicing is essential to maintain the efficient and safe operation of your boiler. For advice on servicing, you can contact the Alpha Helpline directly on 0344 871 8764.

What are the electrical supply requirements for the Alpha E-Tec Plus 28?

The boiler requires a 230/240 V ~ 50 Hz supply, fused at 3 A. The appliance must be earthed. Ensure correct wiring: green/yellow to Earth (E), blue to Neutral (N), and brown to Live (L) terminals.

What is the warranty period for the Alpha E-Tec Plus 28?

The standard warranty period for the Alpha E-Tec Plus 28 is not specified in the provided data. However, warranty registration is required. Always refer to the manufacturer's current terms and conditions for specific warranty details and any extended options available.

What does fault code 01 mean on an Alpha E-Tec Plus 28?

Fault code 01 indicates an ignition failure, meaning a flame was not detected during the ignition sequence. Likely causes include issues with the gas supply, ignition/sensing electrode, ignition generator, gas valve, PCB connections, or a flue restriction.

What does fault code 01 mean on the Alpha E-Tec Plus 33?

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. Check ignition/sensing electrode, ignition generator or lead, gas valve operation, PCB and wire connections, f…

What does fault code 02 mean on the Alpha E-Tec Plus 33?

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

What does fault code 03 mean on the Alpha E-Tec Plus 33?

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. Check primary flow, heat exchanger air flow, flue restriction, flue sensor, air in primary heat exchanger.

What does fault code 04 mean on the Alpha E-Tec Plus 33?

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

What does fault code 05 mean on the Alpha E-Tec Plus 33?

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

What does fault code 06 mean on the Alpha E-Tec Plus 33?

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

What does fault code 08 mean on the Alpha E-Tec Plus 33?

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. Refer to fault history codes (INFO menu d9). If the fault will not clear, replace PCB.

What does fault code 10 mean on the Alpha E-Tec Plus 33?

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

What does fault code 12 mean on the Alpha E-Tec Plus 33?

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

What does fault code 15 mean on the Alpha E-Tec Plus 33?

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

What does fault code 16 mean on the Alpha E-Tec Plus 33?

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

What does fault code 20 mean on the Alpha E-Tec Plus 33?

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

What does fault code 22 mean on the Alpha E-Tec Plus 33?

PCB fault Likely causes: Replace PCB. Replace PCB.

What does fault code 23 mean on the Alpha E-Tec Plus 33?

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

What does fault code 24 mean on the Alpha E-Tec Plus 33?

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

What does fault code 25 mean on the Alpha E-Tec Plus 33?

PCB fault Likely causes: Replace PCB. Replace PCB.

What does fault code 27 mean on the Alpha E-Tec Plus 33?

Primary circuit overheat Likely causes: Air in heat exchanger; Isolation/system valves closed; Check wiring/power to pump; Pump seized/blocked; Pump failed. Check air in heat exchanger, isolation/system valves, pump wiring/power, pump for seizure/blockage, pump failure.

What does fault code 29 mean on the Alpha E-Tec Plus 33?

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

What does fault code 31 mean on the Alpha E-Tec Plus 33?

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). Check remote control or receiver connection wiring, RF signal…

What does fault code 37 mean on the Alpha E-Tec Plus 33?

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

What does fault code 38 mean on the Alpha E-Tec Plus 33?

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. Check flame sensing electr…

What does fault code 43 mean on the Alpha E-Tec Plus 33?

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

← Browse all Alpha boilers

Alpha

E-Tec Plus 33

The Alpha E-Tec Plus 28 is a 28 kW natural gas or LPG combi boiler with an ErP A-rating for heating and hot water, offering a DHW flow rate of 14.1 lpm at a 30°C rise.

The Alpha E-Tec Plus 28 is a wall-hung natural gas or LPG combi boiler designed for domestic heating and hot water provision. Introduced in 2018, this condensing appliance offers a maximum central heating output of 26.1 kW and a domestic hot water output of 28.3 kW. It is a key model within the Alpha E-Tec Plus product family, identified by GC number 47 532 77. This page provides comprehensive technical specifications, fault code diagnostics, and a list of common replacement parts, serving as a reference for UK gas and heating engineers.

CH output: 26.1 kW
DHW flow (∆30°C): 14.1 L/min
NOx class: 6

E-Tec Plus 33 at a glance

Type: combi · natural_gas / lpg
Output: 26.1 kW heating · 28.3 kW hot water
Efficiency: 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 77

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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
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E-Tec Plus 33 data sheet

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

Identification▼

Model name: E-Tec Plus 28
Model number: E-Tec Plus 28
Manufacturer: Alpha
GC number: 47 532 77
Product family: E-Tec Plus
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): 26.1 kW
DHW output (max): 28.3 kW
Heat input (net): 28.8 kW
Heat input (gross): 32 kW

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 heating: A
ErP DHW: A
ErP DHW profile: XL
NOx class: 6
NOx emissions: 35 mg/kWh
Part-load efficiency: 97.6 %

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

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
Max DHW pressure: 8 bar
Expansion vessel: 8 L
EV pre-charge: 1 bar
Water content: 80 L
PRV setting: 3 bar

Electrical▼

Voltage: 220 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): 6 m

Controls▼

Compatible controls: Alpha Easy-Stat wireless programmable room thermostat, 24hr mechanical heating clock (boiler mounted), Alpha Climatic wired programmable boiler energy manager, Alpha Climatic wireless programmable boiler energy manager (boiler mounted receiver), External weather compensation sensor
OpenTherm compatible: Yes
Weather compensation: Yes
Built-in timer: Yes

Safety▼

Safety devices: prv, frost_protection, overheat, flame_failure, low_water
Frost protection: Yes
Flame detection: electronic
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
Min flow rate: 1.5 L/min

Following Part L Building Regulations, where the mains water hardness exceeds 200 parts per million, provision should be made to treat the feed water to the hot water circuit of combination boilers to reduce the rate of accumulation of limescale.

Warranty▼

Registration required: Yes

Compliance▼

CE / UKCA marked: Yes
ErP compliant: Yes

Engineer's overview

The Alpha E-Tec Plus 28 operates with a seasonal efficiency of 93%, achieving an ErP A-rating for both heating and domestic hot water, with an XL DHW profile. Its modulation range allows for a minimum central heating output of 4.3 kW, contributing to efficient operation during periods of lower heat demand. For domestic hot water, the boiler delivers a flow rate of 14.1 litres per minute at a 30°C temperature rise, suitable for typical household requirements. The unit features a stainless steel primary heat exchanger and a plate secondary heat exchanger, ensuring robust performance. Installation requires clearances of 450 mm at the front, 5 mm at the sides, 235 mm at the top, and 150 mm at the bottom. It is compatible with OpenTherm controls and includes built-in frost protection.

E-Tec Plus 33 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-plus-33#fault-01 to jump straight to the entry.

Complete list of fault codes for this Alpha E-Tec Plus 33
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 Engineer action Check ignition/sensing electrode, ignition generator or lead, gas valve operation, 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 * Engineer action Check pump operation, heat exchanger for blockage, air in heat exchanger, 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 Engineer action Check primary flow, heat exchanger air flow, flue restriction, flue sensor, 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 Engineer action Check gas valve lead connection, gas valve, PCB.	Details
05	CH flow sensor fault Show causes & actions Incorrect flow sensor resistance value Likely causes Flow sensor wire connections or sensor faulty Engineer action Check flow sensor wire connections or sensor.	Details
06	DHW sensor fault Show causes & actions DHW sensor resistance value is incorrect Likely causes DHW sensor wiring connection or sensor faulty Engineer action Check DHW sensor wiring connection or sensor.	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 Reset by turning the boiler off and on. Engineer action Refer to fault history codes (INFO menu d9). If the fault will not clear, replace PCB. Reset procedure Turn 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 Engineer action Check expansion vessel pressure, system for leaks, expansion relief valve, 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 Engineer action Check sensor wiring and connections, 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 Engineer action 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 Engineer action Check fan wiring connections, fan, PCB.	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 Engineer action Check flame sensing electrode and lead, electrical short circuit on sensing wires, PCB.	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 Engineer action Check sensor wiring and connections, 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 Engineer action Check for jammed control panel buttons, 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 Engineer action Check air in heat exchanger, isolation/system valves, pump wiring/power, pump for seizure/blockage, pump failure.	Details
29	Flue sensor fault Show causes & actions Flue sensor resistance out of range Likely causes Check sensor wiring and connections Check sensor resistance Engineer action Check sensor wiring and connections, 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) Engineer action Check remote control or receiver connection wiring, RF signal distance/interference, 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 Engineer action Check mains power supply, bad cable connections.	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 Engineer action Check flame sensing electrode and lead, flue gas recirculation, gas valve, flue system and termination, gas supply/working pressure, combustion settings, 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 Engineer action 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 Engineer action 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 Engineer action Check air in heat exchanger, primary flow, heat exchanger air flow, flue restriction, flue sensor, pump.	Details
51	Climatic RF communication fault Show causes & actions Error between communication of the Climatic transmitter and boiler receiver Likely causes Batteries require replacing Engineer action Replace batteries.	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 Engineer action Check pump operation, free pump shaft if necessary, check pump wiring, replace 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 Engineer action Check flow and return valves, system pressure, purge system.	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 Engineer action Check sensor wiring and connections, sensor resistance, 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 Engineer action Check sensor wiring and connections, 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 Engineer action Check sensor wiring and connections, 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 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 Reset procedure Pressing the RESET button will clear the 'Sr' code for 24 hrs to allow the display to be read.	Details
Boiler completely turned off	Boiler completely turned off Show causes & actions Screen only shows a single dot to indicate boiler is completely off Engineer action Press mode button (1) for 2 seconds then release. Boiler display will return and you can select an operating mode Reset procedure Press mode button (1) for 2 seconds then release.	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 Engineer action Check power supply, pump for free rotation, boiler components for excessive current.	Details

Common E-Tec Plus 33 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 Plus 33 overheat boiler lock outLockout

Engineer: Check pump operation, heat exchanger for blockage, air in heat exchanger, external valves/circuit.

Triggered by fault code 02.

How to fix the E-Tec Plus 33 max. number of resetsLockout

User: Reset by turning the boiler off and on.

Engineer: Refer to fault history codes (INFO menu d9). If the fault will not clear, replace PCB.

Triggered by fault code 08.

How to fix the E-Tec Plus 33 ignition failure

Engineer: Check ignition/sensing electrode, ignition generator or lead, gas valve operation, PCB and wire connections, flue restriction or blockage.

Triggered by fault code 01.

How to fix the E-Tec Plus 33 high flue temperature

Engineer: Check primary flow, heat exchanger air flow, flue restriction, flue sensor, air in primary heat exchanger.

Triggered by fault code 03.

How to fix the E-Tec Plus 33 gas valve electrical connection fault

Engineer: Check gas valve lead connection, gas valve, PCB.

Triggered by fault code 04.

Likely causes that trigger multiple E-Tec Plus 33 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 Plus 33 FAQs

Common questions from engineers and homeowners about the Alpha E-Tec Plus 33.

How do I register an Alpha E-Tec Plus 28 with BoilerTag?: To register an Alpha E-Tec Plus 28, scan the QR code on the BoilerTag sticker after installation. The system will pre-fill model details from the appliance catalogue. Record the installation date and your Gas Safe number. Every future service log becomes a permanent, publicly viewable record. The first 12 BoilerTag stickers are free for engineers. Order free BoilerTag stickers from the engineer dashboard.
What is the Alpha E-Tec Plus 28?: The Alpha E-Tec Plus 28 is a 28 kW natural gas or LPG combi boiler with an ErP A-rating for heating and hot water, introduced in 2018. It is a wall-hung condensing appliance suitable for domestic installations requiring both central heating and instantaneous hot water.
What are the required clearances for installing an Alpha E-Tec Plus 28?: Installation requires specific clearances: 235 mm at the top for horizontal flues (150 mm for vertical), 150 mm at the bottom, 5 mm on each side, and 450 mm at the front. Do not store articles or combustible materials on or near the boiler or flue pipe.

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 Plus 33

The Alpha E-Tec Plus 28 is a 28 kW natural gas or LPG combi boiler with an ErP A-rating for heating and hot water, offering a DHW flow rate of 14.1 lpm at a 30°C rise.

CH output: 26.1 kW
DHW flow (∆30°C): 14.1 L/min
NOx class: 6

E-Tec Plus 33 at a glance

Type: combi · natural_gas / lpg
Output: 26.1 kW heating · 28.3 kW hot water
Efficiency: 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 77

Register this Alpha E-Tec Plus 33 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 Plus 33 right now?

Try the free AI fault diagnostics tool — no signup needed.

Open the diagnostics tool →

E-Tec Plus 33 data sheet

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

Identification▼

Model name: E-Tec Plus 28
Model number: E-Tec Plus 28
Manufacturer: Alpha
GC number: 47 532 77
Product family: E-Tec Plus
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): 26.1 kW
DHW output (max): 28.3 kW
Heat input (net): 28.8 kW
Heat input (gross): 32 kW

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 heating: A
ErP DHW: A
ErP DHW profile: XL
NOx class: 6
NOx emissions: 35 mg/kWh
Part-load efficiency: 97.6 %

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

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
Max DHW pressure: 8 bar
Expansion vessel: 8 L
EV pre-charge: 1 bar
Water content: 80 L
PRV setting: 3 bar

Electrical▼

Voltage: 220 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): 6 m

Controls▼

Compatible controls: Alpha Easy-Stat wireless programmable room thermostat, 24hr mechanical heating clock (boiler mounted), Alpha Climatic wired programmable boiler energy manager, Alpha Climatic wireless programmable boiler energy manager (boiler mounted receiver), External weather compensation sensor
OpenTherm compatible: Yes
Weather compensation: Yes
Built-in timer: Yes

Safety▼

Safety devices: prv, frost_protection, overheat, flame_failure, low_water
Frost protection: Yes
Flame detection: electronic
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
Min flow rate: 1.5 L/min

Warranty▼

Registration required: Yes

Compliance▼

CE / UKCA marked: Yes
ErP compliant: Yes

Engineer's overview

E-Tec Plus 33 fault codes

Complete list of fault codes for this Alpha E-Tec Plus 33
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 Engineer action Check ignition/sensing electrode, ignition generator or lead, gas valve operation, 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 * Engineer action Check pump operation, heat exchanger for blockage, air in heat exchanger, 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 Engineer action Check primary flow, heat exchanger air flow, flue restriction, flue sensor, 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 Engineer action Check gas valve lead connection, gas valve, PCB.	Details
05	CH flow sensor fault Show causes & actions Incorrect flow sensor resistance value Likely causes Flow sensor wire connections or sensor faulty Engineer action Check flow sensor wire connections or sensor.	Details
06	DHW sensor fault Show causes & actions DHW sensor resistance value is incorrect Likely causes DHW sensor wiring connection or sensor faulty Engineer action Check DHW sensor wiring connection or sensor.	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 Reset by turning the boiler off and on. Engineer action Refer to fault history codes (INFO menu d9). If the fault will not clear, replace PCB. Reset procedure Turn 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 Engineer action Check expansion vessel pressure, system for leaks, expansion relief valve, 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 Engineer action Check sensor wiring and connections, 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 Engineer action 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 Engineer action Check fan wiring connections, fan, PCB.	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 Engineer action Check flame sensing electrode and lead, electrical short circuit on sensing wires, PCB.	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 Engineer action Check sensor wiring and connections, 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 Engineer action Check for jammed control panel buttons, 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 Engineer action Check air in heat exchanger, isolation/system valves, pump wiring/power, pump for seizure/blockage, pump failure.	Details
29	Flue sensor fault Show causes & actions Flue sensor resistance out of range Likely causes Check sensor wiring and connections Check sensor resistance Engineer action Check sensor wiring and connections, 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) Engineer action Check remote control or receiver connection wiring, RF signal distance/interference, 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 Engineer action Check mains power supply, bad cable connections.	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 Engineer action Check flame sensing electrode and lead, flue gas recirculation, gas valve, flue system and termination, gas supply/working pressure, combustion settings, 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 Engineer action 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 Engineer action 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 Engineer action Check air in heat exchanger, primary flow, heat exchanger air flow, flue restriction, flue sensor, pump.	Details
51	Climatic RF communication fault Show causes & actions Error between communication of the Climatic transmitter and boiler receiver Likely causes Batteries require replacing Engineer action Replace batteries.	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 Engineer action Check pump operation, free pump shaft if necessary, check pump wiring, replace 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 Engineer action Check flow and return valves, system pressure, purge system.	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 Engineer action Check sensor wiring and connections, sensor resistance, 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 Engineer action Check sensor wiring and connections, 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 Engineer action Check sensor wiring and connections, 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 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 Reset procedure Pressing the RESET button will clear the 'Sr' code for 24 hrs to allow the display to be read.	Details
Boiler completely turned off	Boiler completely turned off Show causes & actions Screen only shows a single dot to indicate boiler is completely off Engineer action Press mode button (1) for 2 seconds then release. Boiler display will return and you can select an operating mode Reset procedure Press mode button (1) for 2 seconds then release.	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 Engineer action Check power supply, pump for free rotation, boiler components for excessive current.	Details

Common E-Tec Plus 33 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 Plus 33 overheat boiler lock outLockout

Engineer: Check pump operation, heat exchanger for blockage, air in heat exchanger, external valves/circuit.

Triggered by fault code 02.

How to fix the E-Tec Plus 33 max. number of resetsLockout

User: Reset by turning the boiler off and on.

Engineer: Refer to fault history codes (INFO menu d9). If the fault will not clear, replace PCB.

Triggered by fault code 08.

How to fix the E-Tec Plus 33 ignition failure

Engineer: Check ignition/sensing electrode, ignition generator or lead, gas valve operation, PCB and wire connections, flue restriction or blockage.

Triggered by fault code 01.

How to fix the E-Tec Plus 33 high flue temperature

Engineer: Check primary flow, heat exchanger air flow, flue restriction, flue sensor, air in primary heat exchanger.

Triggered by fault code 03.

How to fix the E-Tec Plus 33 gas valve electrical connection fault

Engineer: Check gas valve lead connection, gas valve, PCB.

Triggered by fault code 04.

Likely causes that trigger multiple E-Tec Plus 33 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 Plus 33 FAQs

Common questions from engineers and homeowners about the Alpha E-Tec Plus 33.

How do I register an Alpha E-Tec Plus 28 with BoilerTag?: To register an Alpha E-Tec Plus 28, scan the QR code on the BoilerTag sticker after installation. The system will pre-fill model details from the appliance catalogue. Record the installation date and your Gas Safe number. Every future service log becomes a permanent, publicly viewable record. The first 12 BoilerTag stickers are free for engineers. Order free BoilerTag stickers from the engineer dashboard.
What is the Alpha E-Tec Plus 28?: The Alpha E-Tec Plus 28 is a 28 kW natural gas or LPG combi boiler with an ErP A-rating for heating and hot water, introduced in 2018. It is a wall-hung condensing appliance suitable for domestic installations requiring both central heating and instantaneous hot water.
What are the required clearances for installing an Alpha E-Tec Plus 28?: Installation requires specific clearances: 235 mm at the top for horizontal flues (150 mm for vertical), 150 mm at the bottom, 5 mm on each side, and 450 mm at the front. Do not store articles or combustible materials on or near the boiler or flue pipe.

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 Plus 33 at a glance

Register this Alpha E-Tec Plus 33 on BoilerTag

E-Tec Plus 33 data sheet

Engineer's overview

E-Tec Plus 33 fault codes

Common E-Tec Plus 33 problems & troubleshooting

How to fix the E-Tec Plus 33 overheat boiler lock outLockout

How to fix the E-Tec Plus 33 max. number of resetsLockout

How to fix the E-Tec Plus 33 ignition failure

How to fix the E-Tec Plus 33 high flue temperature

How to fix the E-Tec Plus 33 gas valve electrical connection fault

Likely causes that trigger multiple E-Tec Plus 33 fault codes

E-Tec Plus 33 FAQs

What should I know about the flue terminal of the Alpha E-Tec Plus 28?

Is annual servicing required for the Alpha E-Tec Plus 28?

What are the electrical supply requirements for the Alpha E-Tec Plus 28?

What is the warranty period for the Alpha E-Tec Plus 28?

What does fault code 01 mean on an Alpha E-Tec Plus 28?

Common service parts

Every boiler brochure, free with BoilerTag

Other Alpha boilers

Working on a Alpha E-Tec Plus 33?

E-Tec Plus 33 at a glance

Register this Alpha E-Tec Plus 33 on BoilerTag

E-Tec Plus 33 data sheet

Engineer's overview

E-Tec Plus 33 fault codes

Common E-Tec Plus 33 problems & troubleshooting

How to fix the E-Tec Plus 33 overheat boiler lock outLockout

How to fix the E-Tec Plus 33 max. number of resetsLockout

How to fix the E-Tec Plus 33 ignition failure

How to fix the E-Tec Plus 33 high flue temperature

How to fix the E-Tec Plus 33 gas valve electrical connection fault

Likely causes that trigger multiple E-Tec Plus 33 fault codes

E-Tec Plus 33 FAQs

What should I know about the flue terminal of the Alpha E-Tec Plus 28?

Is annual servicing required for the Alpha E-Tec Plus 28?

What are the electrical supply requirements for the Alpha E-Tec Plus 28?

What is the warranty period for the Alpha E-Tec Plus 28?

What does fault code 01 mean on an Alpha E-Tec Plus 28?

Common service parts

Every boiler brochure, free with BoilerTag

Other Alpha boilers

Working on a Alpha E-Tec Plus 33?