Alpha E70 Fault Code: Causes, Fixes & Repair Costs
What does the Alpha E70 fault code mean?
The Alpha E70 fault code is not a universally standardised code that appears across all Alpha boiler models, and it is not listed in widely available public fault-code databases. It may be a model-specific code found in certain Alpha ranges such as the E-Tec Plus, Protec Plus, or Evoke, or it is possible that the display is showing a similar code such as E60 or E07 that has been misread — particularly on older LED-style displays where segments can be hard to distinguish. Until confirmed against your specific boiler's manual, E70 should be treated as an undiagnosed fault requiring professional investigation. If you are seeing this code, the most reliable first steps are to check your boiler's model-specific manual (available on Alpha's website) and, if the fault persists, to contact Alpha directly or arrange a visit from a Gas Safe registered engineer who can look up the exact code for your model and carry out a proper diagnosis.
General guidance only — not a substitute for professional advice. Any gas work must be carried out by a Gas Safe registered engineer. If you smell gas or suspect carbon monoxide, leave the property and call the National Gas Emergency line on 0800 111 999.
Common causes
- Misread fault code on LED display Common
On Alpha boilers with segmented LED displays, certain digits can look similar — E70 could easily be mistaken for E60 (a confirmed fan fault) or E07. Before assuming E70 is the actual code, check the display carefully and cross-reference with your model's manual. E60 in particular is a common fan-related fault on Alpha boilers and may be the code actually showing.
- Model-specific sensor or thermistor fault Sometimes
In some Alpha models, codes in the E70 range relate to temperature sensor or thermistor readings that fall outside expected parameters. A faulty NTC sensor — whether on the flow, return, or flue — can trigger codes in this numerical region. Sensors degrade over time or can develop poor electrical connections.
- PCB communication or detection fault Rare
Alpha PCB faults tend to appear in the E83–E85 range, but on some specific models a code near E70 may indicate the PCB has detected an anomaly in a monitored circuit. This is a less common cause but worth considering if no other explanation fits after a Gas Safe engineer checks the boiler.
How to fix it
- Check you are reading the display correctly DIY safe
Look closely at the display. On LED segment displays, the number 6 and 7 can appear similar, as can 0 and certain letter shapes. If the code is E60, that points specifically to a fan fault. Your boiler's model and serial number are usually printed on the front casing — note these down before calling for help.
- Consult your boiler's model-specific manual DIY safe
Alpha publishes installation and user manuals for all its boiler ranges on its official website. Search for your exact model (e.g. E-Tec Plus, Protec Plus) and look up the fault code list. The E70 definition, if it exists for your model, will be documented there. This is the single most reliable way to confirm what the code means on your specific boiler.
- Check that your gas supply is active DIY safe
Make sure other gas appliances in your home, such as a gas hob or fire, are working normally. If they are not, there may be a wider gas supply issue and you should contact your gas supplier. Do not attempt to investigate gas pipework yourself.
- Check and restore boiler system pressure if low DIY safe
Look at the pressure gauge on your boiler — it should read between 1.0 and 1.5 bar when cold. If it is below 1.0 bar, top it up via the filling loop following the instructions in your user manual. Over-pressurising (above 2.5 bar) can cause further faults, so proceed carefully.
- Attempt a boiler reset DIY safe
Press and hold the reset button (usually marked with a flame or reset symbol) for around 3 seconds. Allow the boiler a few minutes to restart and attempt ignition. If the fault clears and the boiler runs normally, monitor it over the next day or two. Do not reset more than two or three times — repeated resets without resolution can mask a more serious underlying problem.
- Contact Alpha customer support or a Gas Safe registered engineer Gas Safe engineer
If the fault code persists, or if you cannot confirm the meaning of E70 for your specific model, call Alpha's customer helpline or book a visit from a Gas Safe registered engineer. An engineer can retrieve the live fault history from the boiler, identify the exact component at fault, and carry out any necessary repair safely and legally. Do not remove the boiler casing or attempt internal checks yourself.
Parts you may need
- NTC flow or return thermistor sensor · from £25
- Boiler fan assembly (Alpha-compatible) · from £150
- PCB (model-specific Alpha replacement) · from £220
The exact spare depends on your boiler's GC number (on the data badge). Check this against the part before buying.
Typical repair cost
Expect to pay roughly £120–£350, depending on the underlying cause.
Frequently asked questions
Is E70 a serious fault on my Alpha boiler?
Until confirmed against your specific model's manual, it is sensible to treat any unrecognised fault code seriously. The boiler has flagged something outside its normal operating parameters. While some faults in this range are relatively straightforward — such as a sensor replacement — others may require more involved work. Avoid repeated resets and arrange for a Gas Safe engineer to investigate if the fault does not clear after one or two resets.
Could my Alpha boiler actually be showing E60 rather than E70?
Yes, this is worth checking. E60 is a confirmed fan fault on Alpha boilers and appears on multiple models. On LED segment displays, the digit 6 and digit 7 can look alike depending on lighting conditions and the angle you are viewing the display. If your boiler is also making unusual noises from the fan area, or the fan is not running, E60 is a strong candidate. A replacement fan typically costs £225–£275 including labour.
What does the Alpha E70 fault code mean on the E-Tec Plus specifically?
The E70 code is not consistently documented across public sources for the E-Tec Plus range. Your best course of action is to download the official E-Tec Plus service manual from Alpha's website and check the fault code appendix, or call Alpha's technical helpline with your boiler's model number and serial number to hand. A Gas Safe engineer who works regularly with Alpha boilers may also have access to manufacturer service documentation that goes beyond what is publicly available.
How much will it cost to fix an Alpha boiler showing E70?
Because the exact fault behind E70 is not confirmed without a professional diagnosis, costs vary. Most common faults — such as a sensor replacement or a pressure-related fix — typically cost between £120 and £350 including labour and parts. If the fault turns out to involve the fan, budget around £225–£275. In the less likely scenario that a PCB replacement is needed, costs can rise to £400 or more. If your boiler is over 10 years old and facing a repair bill above £400, it may be worth comparing that against the cost of a new boiler installation.