Alpha 0E98 Fault Code: Causes, Fixes & Repair Costs
What does the Alpha 0E98 fault code mean?
The 0E98 (also displayed as E98) fault code on Alpha boilers indicates a Hardware Error 3 — a critical internal fault that the boiler's main control board (PCB) has detected and cannot resolve on its own. The PCB is the electronic brain of the boiler, responsible for coordinating ignition, fan operation, safety monitoring, and communication between all electrical components. When E98 appears, the board has flagged a hardware-level problem serious enough to lock out the boiler. Alpha's own diagnostic guidance also recommends checking the error history for a secondary F36 code, as E98 can sometimes accompany or be triggered alongside that fault — if you find F36 in the fault log, investigate that code as well. A mains supply frequency issue is another documented trigger, which is why a power cycle is the first recommended step before calling an engineer.
General guidance only — not a substitute for professional advice, and not certified by a Gas Safe engineer. Always have your specific appliance assessed by a qualified professional. 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
- Internal PCB hardware failure Common
The control board itself has developed a fault it cannot self-correct — this could be degraded components on the board, a corrupted processor state, or age-related electronic failure. This is the most direct cause of an E98 lockout and typically requires the PCB to be replaced by a Gas Safe engineer.
- Mains supply frequency or power irregularity Common
Alpha's own guidance flags a problem with the mains frequency as a probable cause of E98. A spike, dip, or instability in the incoming electrical supply can confuse the PCB and trigger a hardware error. A power cycle (switching the boiler off at the mains and back on) can clear this if the supply has since stabilised.
- Loose or damaged internal wiring Sometimes
The boiler contains many wiring harnesses connecting sensors, actuators, and the PCB. A connection that has vibrated loose, corroded, or partially failed can cause the board to register a hardware-level fault. An engineer will inspect all wiring connectors and terminals as part of diagnosis.
- Internal water leak damaging the PCB Sometimes
A slow leak from a heat exchanger, pump seal, or internal fitting can allow water or moisture to reach the PCB. Corrosion or a direct short caused by water ingress can trigger a hardware error. A burning smell alongside E98 is a warning sign that this may have occurred.
- Faulty sensor causing misdiagnosis Rare
On rare occasions, a failing sensor (such as a flow thermistor or flame sensor) sends anomalous signals to the PCB that the board interprets as a hardware fault rather than a sensor fault. An engineer can check sensor readings to rule this out before committing to a PCB replacement.
How to fix it
- Power cycle the boiler at the mains DIY safe
Switch the boiler off at the fused spur or isolation switch, leave it off for at least 30 seconds, then switch it back on. A mains frequency or transient power irregularity can cause E98, and a full power cycle — rather than just pressing reset — gives the PCB the best chance of clearing a spurious fault.
- Check the boiler's fault history for a secondary F36 code DIY safe
Alpha boilers store a fault log accessible via the control panel. If F36 appears alongside or before E98, this secondary code provides an additional clue for your engineer. Note down any codes you find and pass them on — it can save diagnostic time and cost.
- Attempt a single boiler reset DIY safe
If the power cycle did not clear the fault, press and hold the reset button as described in your boiler's user guide. Attempt this only once. If E98 returns immediately or within a short time, stop resetting — repeated resets on a genuine PCB fault can cause further stress to the board and are unlikely to help.
- Check for signs of a water leak inside the boiler casing DIY safe
Without removing the boiler casing (which must only be done by a Gas Safe engineer), check around the base of the boiler and pipework for drips or water staining. Note any burning smell, which could indicate moisture has reached the PCB. Report your findings to the engineer you call.
- Contact a Gas Safe registered engineer for full diagnosis Gas Safe engineer
E98 is a hardware-level PCB fault that almost always requires professional diagnosis. An engineer will inspect the wiring harness, test sensor outputs, check mains voltage and frequency at the boiler terminals, and assess whether the PCB needs reprogramming or full replacement. Do not attempt to remove the boiler casing or access internal components yourself — this is a legal requirement as well as a safety necessity.
Parts you may need
- Replacement PCB (main control board) — Alpha specific · from £280
- Wiring harness / internal loom · from £65
- Flow thermistor (NTC sensor) · from £18
- Flame detection electrode · from £22
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 £350–£650, depending on the underlying cause.
Frequently asked questions
Can I fix Alpha fault code E98 myself?
Not beyond the basic checks listed above. You can safely power cycle the boiler, check the fault log, and attempt a single reset. Beyond that, E98 is a PCB-level hardware fault and all further work must be carried out by a Gas Safe registered engineer. Removing the boiler casing without Gas Safe registration is both unsafe and a legal issue in the UK.
How much does it cost to fix an Alpha E98 fault in the UK?
Most homeowners pay between £350 and £650 for a PCB-related repair including callout, labour, parts, and VAT. The PCB itself typically costs £180–£400 depending on the specific Alpha model. If the board turns out not to need replacement — for example, if a loose wiring connection is the root cause — the bill will be considerably lower. In rare cases where the PCB is irreparable and difficult to source for an older model, costs can be higher, which is when a replacement boiler starts to make financial sense.
What is the F36 code that Alpha recommends checking alongside E98?
Alpha's diagnostic guidance specifically links E98 to F36 in some scenarios. F36 on Alpha boilers typically relates to a fan or air pressure fault. If F36 appears in your boiler's fault history alongside E98, it may indicate that a secondary component failure contributed to the PCB error, rather than the board failing in isolation. Pass this information to your engineer — it could change the diagnosis and potentially reduce the repair cost.
Is it worth repairing an Alpha boiler with an E98 fault, or should I replace it?
If your Alpha boiler is under 10 years old and otherwise in good condition, a PCB replacement is usually worthwhile and can restore years of reliable operation. If the boiler is over 12–15 years old, has had other recent repairs, or is out of warranty, compare the repair quote against the cost of a new boiler. As a general rule of thumb, if the repair costs more than half the price of a new equivalent boiler, replacement often delivers better long-term value.