Updated: 14th August, 2024
Some of the most common Alpha boiler error codes and what they mean
Alpha boiler error codes can be a nuisance, but it is often relatively easy to fix your alpha boiler once you check the fault code being displayed on the control panel electrode.
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From water pressure problems to a sensor fault, issues with flow sensor, flue sensor, or even heat exchanger, we will run you through some common boiler fault types, how to check them and fix them.
Read on below to find out everything about boiler error codes and how to check them in alpha boilers.
Fault Code | Fault | Possible Cause |
|---|---|---|
1 | Ignition failure | Gas supply, pressure tubes, ignition electrode, flame sensor electrode, ignition generator, lead flame sensor, electrode lead, gas valve setting, gas valve printed circuit board (PCB) |
2 | Overheat boiler lock out | Pump or flow problem, blocked heat exchanger, air in heat exchanger, overheat thermostat, thermal fuse (if open circuit then replace primary heat exchanger) |
3 | High flue thermostat temperature | Blocked or restricted primary flow, heat exchanger air flow blocked, flue restriction, flue sensor fault |
4 | Gas valve electrical connection fault | Gas valve lead connection fault, faulty gas valve or faulty printed circuit board (PCB) |
5 | Heating flow sensor fault | Flow sensor wire connections, flow sensor faulty |
6 | Domestic how water (DHW) sensor fault | DHW sensor wiring connection or DHW sensor faulty |
8 | Maximum number of resets | Refer to fault history codes |
10 | Primary system pressure low | Check expansion vessel pressure (1 bar), leak in system, expansion relief valve operated or primary pressure switch |
12 | Cylinder sensor fault (FlowSmart only) | Cylinder sensor wiring connections or cylinder sensor faulty |
15 | Internal wiring error | Check internal wiring connections to printed circuit board (PCB), Combi boiler domestic hot water (DHW) sensor X4, System boiler link X14 |
16 | Fan fault | Fan wiring connections, fan fault or printed circuit board (PCB) fault |
20 | Flame sensing fault | Check flame sensing electrode and lead printed circuit board (PCB) fault |
24 | Control panel button fault | Jammed control panel or printed circuit board (PCB) buttons |
25 | Overheat lock out | Air in heat exchanger, blocked or restricted primary flow, heat exchanger air flow blocked, flue restriction, flue sensor fault, pump fault, boiler or heating circuit valve closed |
27 | Insufficient primary flow | Blocked or restricted primary flow, air in heat exchanger, boiler or heating circuit valve closed, pump fault or primary flow sensor fault |
29 | Flue sensor fault | Sensor wiring connection or flue sensor faulty |
31 | Loss of communication with external control (Alpha Climatic) | Remote control or receiver connection wiring |
37 | Low supply voltage | Check mains power supply |
38 | Loss of flame rectification | Flame sensing electrode and lead, check flue gas recirculation, check the gas valve settings and check the fan speed settings |
43 | Loss of flame rectification | Check gas supply working, check flame sensing electrode and lead, check for flue gas recirculation, check the gas valve settings, check the fan speed settings |
44 | Safety lock out | Check external control (room thermostat) requests and rapid on/off hot tap requests |
46 | External sensor intervention | External sensor and cable damaged or wet, continuity of external sensor and circuit, check connection at X19 on printed circuit board (PCB) and sensor connecting block |
47 | Reduced burner output | Air in heat exchanger, restricted primary flow, heat exchanger air flow blocked, flue restriction, flue sensor fault or pump fault |
51 | Climatic RF communication fault | Batteries need replacing, distance between boiler and climatic control too great, interference object blocking signal (metallic) |
60 | Pump error (stuck or there is an electrical pump fault) | Pump operation (may need to free the pump shaft), issue with pump wiring or pump replacement needed. |
61 | Air in the pump (restricted central heating flow) | Flow and Return valves may not be open, iIncorrect system pressure, system not purged properly or flow return valves are open. |
70 | Return/flow sensor, Exchange from possible wiring fault | Issues with sensor resistance. |
75 / 76 | Return/flow sensor fault from possible failure of one or both sensors | Issues with sensor resistance. |
SR | Service reminder | Service reminder countdown has reached 0 (this will not stop boiler from working) _ boiler needs servicing. |
0A1 | Ignition failure | Issue with gas supply. |
0A2 | Flame detection fault | Flame sensing electrode connections. |
0A3 | Overheat thermostat lock-out | Flame sensing electrode connections. |
0A5 | Fan speed fault | Problem with flue /ventilation. |
0A7 | High flue temperature fault | Air in the primary heat exchanger. |
0A8 | Flame circuit fault | Incorrect gas supply. |
0A9 | Gas valve electrical error | Valve connection issues. |
0A15 | Flow and return sensor anomaly detected. | Poor or incorrect circulation. |
0A16 | Flow sensor temperature rise incorrect (time taken for flow temperature to rise is too long. | System circulation issues. |
0A17 | Return sensor temperature rise incorrect (time taken for flow temperature to rise is too long. | System circulation issues. |
0A18 | Flow and return sensor anomaly detected. Sudden temperature change detected on the flow or return sensor. | System circulation issues. |
0A21 | Main PCB fault | Electrical connections. |
0A30 | Flow sensor short circuit | Flow sensor connections and wires need checking. |
0A31 | Flow sensor out of range. (sensor measures a temperature not in normal range.) | Problem with flow sensor connections and damaged wires. |
0A37 Ð Pro Tec 50 | Insufficient system flow (if the system flow is too low for a certain length of time boiler will switch off) | Flow switch reading needs checking. |
0A37 Ð Pro tec 70, 90, 115 | Insufficient system pressure (if the system pressure is too low the boiler switches off.) | System pressure needs to be 1 – 2 bar if its not the pressure needs refilling to the correct amount |
0A43 | Return sensor short circuit | Problem with return sensor connections and wires. |
0A44 | Return sensor out of range. | Return sensor connections and damaged wires. |
0A80 | Flow and return sensor connection fault (may occur after several minutes of boiler operation.) | Wires are not connected to the correct sensors. |
0E2 | Flame sensing fault. | Flame sensing electrode connections need checking. |
0E13 | Maximum number of resets reached. (Over 5 reset attempts have been reached within 15 minutes.) | Investigate initial fault code displayed. |
0E25 | Main PCB fault | All electrical connections need to be checked. |
0E34 | DHW sensor out of range (measures a temperature outside normal working range.) | DHW sensor connections and damaged cables. |
0E33 | Low power supply voltage | Electrical socket connection issues. |
0E37 | Insufficient system pressure | System needs checking for circulation and restrictions. |
0E45 | Flue sensor short circuit | Flue sensor connections and wires need checking. |
0E46 | Flue sensor out of range (measures a temperature outside of normal working range) | Flue sensor connections, wires and flue sensor resistance values need checking. |
0E81 | Flow and return sensor anomaly detected (the sensor shows an incorrect temperature value) | Poor or incorrect circulation / external circuit influences resistance of flow return sensors need checking |
0E98 | Flow and return sensor anomaly detected (sensor shows incorrect temperature value) | M to O Connections need checking |
0E99 | Simple cascade communication error | Wiring connections needs checking on all boilers. |
FE94 | Display PCB fault. | Electrical connections to display board need checking. |
FE95 | External flow sensor out of range or short circuit/ | External flow sensor connections and wires need checking for damage. External flow sensor resistance values need checking to make sure they are between 5 and 0 |
FE96 | External sensor fault | External sensor connections and wires need checking. |
FE97 | Boiler PCB configuration error (may occur if the main PCB or display PCB is changed.) | All electrical connections. |
No lights on | Electricity fault | Check your electricity supply |
Illuminated red A or B | Burner has failed to light | Rotate selector switch to the reset position (3) and the ignition sequence will restart after a delay of about 30 seconds |
Illuminated yellow B or C | Burner is alight | No action required |
Flashing red A or B | Overheat thermostat has operated / Temperature sensor fault | Rotate selector switch to the reset position (3) to reset |
Flashing yellow every 5 seconds or illuminated green D | Electrical supply to the boiler is on | No Action Required |
Flashing yellow B or flashing Red A | Temperature sensor fault | Contact a heating engineer |
Illuminated red A and flashing yellow B or Flashing red A and flashing red B | Blocked flue or fan fault | |
Flashing yellow or flashing Red A or Flashing (alternating) red A and flashing (alternating) yellow B | System pressure is very low and re-pressurisation is requiredæ | |
Illuminated red A and flashing yellow B | Pump fault or restricted flow | |
Flashing red A and Flashing red B and flashing yellow C | Temperature sensor wiring or flow and return connections incorrect | |
Flashing red A and flashing red B and flashing yellow C indicators | Flue temperature too high (air in the heat exchanger, heat exchanger blocked | |
1 | Ignition failure | Check the gas supply, pressure tubes, ignition electrode, flame sensor electrode, ignition generator or lead flame sensor, gas valve setting and PCB. |
2 | Overheat boiler lockout | Pump or flow problem. Caused by a blocked heat exchanger, air in heat exchanger, overheated thermostat, thermal fuse (if open circuit then replace primary heat exchanger). |
3 | High flue thermostat temperature | Blocked or restricted primary flow. Heat exchanger air flow blocked, flue restriction, flue sensor fault. |
4 | Gas valve electrical connection fault | Gas valve lead connection fault. Faulty gas valve or faulty PCB. |
5 | Heating flow sensor fault | Flow sensor wire connections. Flow sensor faulty. |
6 | Internal wiring error | Incorrect wiring configuration detected. Internal wiring connections to PCB need checking. |
7 | Chimney sweep function is active | Chimney sweep function is active. E07 is displayed on the climatic remote control. |
8 | Maximum number of resets | Refer to fault history codes (INFO menud9) |
12 | Cylinder sensor fault (FlowSmart only) | Cylinder sensor wiring connection _ cylinder sensor faulty. |
16 | Fan fault | Check fan wiring connection, fan fault or PCB fault. |
20 | Flame sensing fault | Check flame sensing electrode and lead PCB for faults. |
23 | Heating return sensor fault | Incorrect return sensor resistance value _ return sensor wire connections or sensor could be faulty. |
24 | Control panel button fault | Control panel button is stuck in the ïonÍ position _ check for jammed control panel buttons or jammed PCB button.æ |
27 | Insufficient primary flow | Blocked or restricted primary flow. Air in heat exchanger, boiler or heating circuit valve closed, pump fault or primary flow sensor fault. |
29 | Flue sensor fault | Check sensor wiring connection _ flue sensor faulty. |
31 | Loss of communication with external control (Alpha Climatic) | Remote control or receiver connection wiring. |
37 | Low supply voltage | Check mains power supply. |
38 | Loss of flame rectification | Check flame sensing electrode and lead and for flue gas recirculation. Check or adjust the gas valve settings. Check or adjust the fan speed settings. |
43 | Loss of flame rectification | Check gas supply/working pressure, flame sensing electrode and lead, check for flue gas recirculation, check/adjust the gas valve settings, check/adjust the fan speed settings. |
44 | Safety lockout | Check external control (room thermostat) requests. Rapid on/off hot tap requests. |
45 | High-temperature difference | The boiler is detecting an unexpected increase between the system flow and return sensors. Boiler output is limited for boiler protection and once restored the boiler resumes regular operation. |
46 | Optional thermostat intervention | No continuity of optional thermostat circuit _ check the optional thermostat and cable are not damaged or wet. |
47 | Reduced burner output | Flue thermostat has sensed high flue gas temperature and reduced the burner output to prevent damage. If the temperature continues to rise the boiler will lockout and the E03 error code will be displayed. This could be due to air in the heat exchanger, restricted primary flow or heat exchanger air blocked. |
49 | Return sensor high temperature intervention | Return sensor has detected a high temperature on the exchanger return circuit. |
51 | Climatic RF communication fault | The error between the communication of the climatic transmitter and boiler receiver. Could mean the batteries need replacing or the distance between the boiler and climatic control is too great or a metal object is blocking the signal.æ |
70 | Return flow sensor erroræ | Possible wiring faults sensor is incorrectly fitted or the system is blocked _ check the sensor wiring and connections, also check sensor resistance and circulation. |
71 | No primary temperature increase detectedæ | From ignition the boiler detects no temperature rise in the primary circuit _ check system filling and venting, air locks preventing flow check, blocked flow or closed valves. |
Alpha boilers display an error code to check through flashing red and yellow lights on the control electrode display.
Different lights will light up flashing, depending on the problem.
If the A indicator light is lit up a solid red rather than flashing red, that is a 47 fault code: the flame burner has failed to light, so you have no heat supply to the boiler.
This is an easy fault to repair.
You just need to reset your boiler by rotating the front selector switch to the reset position. Leave it for 25 to 30 seconds, and your boiler will restart the flame.
If that doesn't help, there is a blockage somewhere, such as in your gas valve.
Call in a gas safe engineer to check and fully clean the burner air flue on your boiler to deal with any blocked parts.
When the red A indicator and the yellow B indicator are flashing, that means that your burner has failed to light its flame for a different reason.
Just like the first flame problem on the list, you can check this and return the control dial to position 3 for a flame reset.
It is more likely that your burner air system pump is blocked or has a fan fault, or the burner component itself is faulty, with a non-functional gas valve closed.
It could also be an issue with the ignition electrode connections, electrical supply circuit connections, or air pump expansion vessel circuit.
In this situation, you should get an engineer to check for a blocked or faulty burner element air fan fault and gas valve fault.
If the red A indicator light is flashing red on and off, but the yellow B indicator light is switched off, then your boiler fault is in the overheat thermostat electrode component. Check your control panel for error code 2 or code 25 return.
Unfortunately, this fault code is one that you will need to call a boiler engineer in to help repair the fault.
There are several different things that can go wrong with your thermostat, including closed-circuit valve connections for the heating system primary flow, pump fault, a problem with the flue sensor connections, your flue outlet being blocked or restricted, a primary flow blockage in flow and return circuit, flue gas recirculation, or even an airlock in the heat exchanger component.
Get an engineer to check the systems for a fault with the primary flow and return, a blocked or restricted gas supply, or a pump fault.
There are many reasons why you might not have any hot water, and most of these are easy to diagnose.
If the power light is not on, then there is no power supply to your boiler. If the fan starts running before the boiler starts trying to ignite, something has gone wrong with the ignition.
If the boiler won't fire up, the problem is in the pilot light, gas supply, or gas valve. If it fires up but then cuts out, then it is probably a gas valve supply issue. Otherwise, you probably have an issue with your diverter valve or flow sensor.
Sometimes, you can release a stuck diverter valve. In most cases, you will need to replace your flow sensor or diverter valve.
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If you have got low boiler pressure, then your boiler probably shows an E10 fault code. It will also show low pressure on the gauge if you check that.
That means that you have lost too much pressure. This indicates that there is a heating system leak somewhere in your home heating system. You can deal with this, but it will take a bit of work.
You will need to check the pressure leak and fix it quickly before it risks damaging your house.
There are two common reasons for your hot water only getting to a warm temperature rather than hot temperature: thermistor sensor fault and limescale build-up.
The thermistor, or thermocouple, on your boiler, monitors the heat exchanger temperature sensor. Faulty sensors are an issue; the temperature sensor tells the boiler to stop heating at that temperature.
If there is a flue sensor fault or connection fault, or even a button fault, then your boiler might not reach the right temperature due to primary flow sensor faulty issues.
Engineers will be able to help you fix the issue. If it is not the thermistor flow sensor fault, then it is probably limescale in your pipes, which will need replacing as soon as possible.
How much is a new boiler? The answer is, well, it depends.
Effectively, new boiler cost can be split into two segments: the first is the actual boiler itself (unit price), and the second is the cost of the boiler being installed (set up) in your property by an expert engineer.
Here at iHeat, we want to remove all of this undue stress and make the decision making process of upgrading to a new central heating system, as easy as possible.
Boiler costs can vary depending on a number of factors including their brand, model, fuel, output, warranty, labour and boiler installation type. Typically a new boiler will cost between £1,845 and £3,500, below is a list of average boiler installations offered by iHeat (guide only).
Installation Type | Price (inc VAT) | |
Combi to combi swap | £1,845 | |
System to combi conversion | £2,499 | |
New boiler install | £2,899 | |
Back boiler to a combi | £3,299 | |
System to system | £1,945 |
The E10 error code on an Alpha boiler typically indicates a problem with the pressure within the boiler system. It suggests that the pressure is too low, which can happen due to leaks in the system, bleeding radiators, or a need for repressurization. The boiler requires a certain pressure level to operate efficiently, and this error signals that it has fallen below that level.
Alpha boilers, like any other brand, can encounter various issues over their lifespan, including error codes, pressure problems, ignition failures, and component wear and tear. Common problems include fluctuating pressure, leaking, error codes indicating specific faults, and intermittent heating or hot water supply. Regular maintenance can help prevent some of these issues and extend the boiler's life.
The E1 error code on an Alpha boiler usually points to an issue with the boiler's thermistor or temperature sensor. It can indicate that the boiler is overheating or that there is a fault in the sensor itself. This requires checking the sensor's connections for faults or replacing the sensor if necessary.
The E27 fault code typically indicates a flame detection fault in the Alpha boiler. This could be due to issues with the ignition, flame sensor, or gas supply. To fix this, you might need to check the gas supply, clean or adjust the flame sensor, and ensure that the ignition electrodes are in good condition. If these steps do not resolve the issue, it may be necessary to contact a certified heating engineer for a more in-depth diagnosis and repair.
If your Alpha boiler is flashing "A" and "B," it's likely indicating a specific fault or operational mode, depending on the model of your Alpha boiler. This could relate to a startup sequence, a specific fault, or a mode of operation. It's essential to refer to your boiler's user manual for an accurate interpretation of these signals and instructions on how to proceed.
A flashing red light on an Alpha boiler generally indicates a fault or lockout condition. This could be due to several issues, including overheating, loss of pressure, or a failure in the ignition process. The exact cause can often be determined by the pattern of the flashing light or an accompanying error code displayed on the boiler.
An Alpha boiler may keep turning off due to several reasons, such as low water pressure, overheating, a blocked condensate pipe, or issues with the thermostat. It might also turn off as a safety measure if it detects a fault in the system. Identifying the specific cause requires checking the boiler's pressure gauge, inspecting for any error codes, and ensuring that there are no blockages in the system. In many cases, resolving these issues might require professional assistance to ensure the boiler operates safely and efficiently.
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