Vokera 05 Fault Code: Causes, Fixes & Repair Costs
What does the Vokera 05 fault code mean?
Fault code 05 on Vokera boilers has two distinct meanings depending on your model. On the Syntesi, Linea, and Linea (original) ranges fitted with the optional RC05 remote control, fault code 05 indicates a communication breakdown between the RC05 unit and the boiler — the boiler cannot 'talk' to its remote control. On the Linea Max and Linea Max HE (which do not use the RC05), code 05 is a lockout fault handled in the same way as an ignition failure (similar to code 01) — the boiler has attempted to fire and been unable to establish or confirm a flame. Identifying which model you have is the essential first step before attempting any checks.
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
- Wiring fault between RC05 remote control and boiler (Syntesi / Linea with RC05 fitted) Common
The RC05 is an optional accessory that, when connected, takes over control of the boiler. Any break, loose connection, or corrosion in the communication cable between the RC05 and the boiler's PCB will trigger fault code 05. This is the single most likely cause on models where the RC05 is installed.
- Failed or faulty RC05 unit Sometimes
The RC05 handset or wall unit itself can develop an internal fault, causing it to stop communicating correctly with the boiler even when the wiring appears intact. This becomes more likely as the unit ages.
- Ignition failure — no flame established (Linea Max / Linea Max HE without RC05) Common
On these models, code 05 is a lockout triggered when the boiler attempts to light and fails. The ignition electrode may be worn, cracked, or incorrectly gapped, preventing a reliable spark from forming at the burner.
- Gas supply issue (Linea Max / Linea Max HE) Common
If gas is not reaching the burner — whether due to a closed meter valve, a prepayment meter running out of credit, or a wider supply interruption — ignition is impossible and the boiler will lock out.
- Faulty gas valve (Linea Max / Linea Max HE) Sometimes
The gas valve controls fuel flow to the burner. If it sticks closed or fails to open fully during the ignition sequence, the boiler locks out because there is nothing to ignite.
- Flame sensor fault (Linea Max / Linea Max HE) Sometimes
The flame sensing electrode monitors whether a burner flame is actually present. A contaminated or degraded sensor can misreport the flame status to the PCB, causing the boiler to abort the ignition sequence and lock out.
- PCB fault Rare
The PCB orchestrates the entire ignition and operating sequence. A fault on the board can disrupt communication with the RC05 or cause a spurious lockout on models without one. PCB faults tend to produce a range of other symptoms alongside the fault code.
How to fix it
- Identify your Vokera model and whether an RC05 remote is fitted DIY safe
Look at the model name on the boiler's front panel or data plate. If you see an RC05 wall-mounted remote control connected to the boiler, the communication fault interpretation applies. If you have a Linea Max or Linea Max HE without an RC05, this is a lockout fault — follow the ignition-failure steps below.
- Check the RC05 wiring (if RC05 is fitted) DIY safe
Inspect the cable running between the RC05 unit and the boiler for obvious damage, kinks, or disconnected terminals. Gently reseat any loose plugs at both ends. Do not open the boiler casing — this visual check is limited to the external cable and the connection points at the back of the RC05 unit and the boiler's wiring terminal strip (accessible without removing covers).
- Check your gas supply DIY safe
Confirm your gas meter isolation valve is fully open (handle in line with the pipe). Check that other gas appliances in the home — a hob burner, for instance — are working normally. If nothing is working, contact your gas supplier. If your supply is fine, move to the next step.
- Reset the boiler DIY safe
Turn the mode selector switch to the reset position and hold it there for approximately 10 seconds, then return it to your normal operating position. On some Linea variants there is a dedicated reset button marked 'R' or a circular arrow — press and hold for 3–5 seconds until the fault code stops flashing. Attempt this no more than two or three times in total. Repeated resetting without resolving the underlying fault can mask a serious problem.
- Call a Gas Safe registered engineer if the fault returns or persists Gas Safe engineer
If the boiler locks out again after resetting, or if the RC05 communication fault reappears, a Gas Safe engineer is needed. They will test the RC05 wiring harness and unit, inspect the ignition and flame-sensing electrodes, check the gas valve operation, and assess the PCB. All work inside the boiler and on its gas components is a legal requirement for Gas Safe registered engineers only.
Parts you may need
- RC05 remote control unit · from £65
- RC05 communication cable / wiring harness · from £25
- Ignition electrode · from £30
- Flame sensing electrode · from £25
- Gas valve · from £90
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–£320, depending on the underlying cause.
Frequently asked questions
Does fault code 05 mean the same thing on all Vokera boilers?
No — and this is one of the most important things to understand about this fault code. On the Syntesi and Linea (with the RC05 remote fitted), code 05 is a communication fault between the remote and the boiler. On the Linea Max and Linea Max HE (without the RC05), it is a lockout fault treated identically to an ignition failure. Always check your model name before assuming which fault you are dealing with.
Can I fix Vokera fault code 05 myself?
Some preliminary checks are safe for a homeowner: visually inspecting the RC05 cable for obvious damage, confirming your gas supply is on, and attempting a reset (up to two or three times). Beyond that, the cause almost certainly involves internal boiler components — electrodes, the gas valve, or the PCB — which legally require a Gas Safe registered engineer to diagnose and repair.
My Vokera keeps showing fault code 05 after I reset it — what does that mean?
A fault that returns repeatedly after resetting is telling you that the underlying problem has not been fixed. On RC05 models, this usually means the wiring or the RC05 unit itself needs professional attention. On Linea Max models it typically points to a faulty ignition electrode, flame sensor, or gas valve. Stop resetting and call a Gas Safe engineer — repeated lockouts can indicate a developing safety issue.
How much will it cost to fix Vokera fault code 05?
For most households, repairs fall in the range of £120–£320 once parts and labour are included. An RC05 wiring repair tends to sit at the lower end (around £120–£200), while replacing an ignition electrode or gas valve typically costs £150–£280. A PCB replacement is less common for this particular fault but can cost considerably more — often £300–£500 — and should be confirmed as necessary by an engineer before committing to the work.