What A10 means on a Vokera boiler
A10 is the flame lockout code on the Vokera Easi-Heat i 25C and 29C. The fault table in section 3 of Vokera's Easi-Heat i users and installation instructions (document 20195442, edition 3) lists it as "Flame lockout" and marks it as definitive, so the boiler stays off until it is reset by hand. In that table, A10 sits alongside two specific conditions: "Condensate drain obstructed" and "Flue gas exhaust/air suction obstructed".
A lockout of this kind is a safety shutdown. When the boiler cannot be sure that gas is burning properly, it closes the gas valve rather than let unburnt gas build up or let flue gases back into the room. The lockout is the boiler doing its job. Your task is to find out why it happened.
A10 replaces A01 on older Vokeras
Older Vokera models such as the Compact A and Unica i use A01 for ignition failure, and their manuals say to reset and, on the Unica i, to check the gas is on. The Easi-Heat i uses the newer two digit code family, so A10 is its equivalent lockout. If your boiler shows A01, use that page instead, because the reset method on those models is different.
The two causes in Vokera's fault table
Condensate drain obstructed
The Easi-Heat i is a condensing boiler, so it produces acidic water that drains through a plastic pipe to a drain. If that pipe freezes or blocks, water backs up inside the boiler and it cannot run safely. The installation section of the manual sets out how the pipe should be run: plastic pipe of at least 21.5 mm outside diameter, falling at least 45 mm per metre away from the boiler, and at least 32 mm with insulation where it runs outside or through unheated space. It also tells installers to make sure the user knows what a blocked or frozen condensate pipe will do. A thin, uninsulated pipe running along an outside wall is the usual winter culprit.
Flue gas exhaust or air intake obstructed
The boiler draws its combustion air in and pushes waste gases out through the flue. If either path is restricted, by a nest, debris, ice, damage or a terminal that has been boxed in, the burner cannot run cleanly and the boiler locks out. Checking and clearing the flue is strictly a job for a Gas Safe registered engineer.
| What you notice | Most likely link to A10 | Who deals with it |
|---|---|---|
| Hard frost, gurgling from the boiler, ice on the outside pipe | Frozen condensate drain | You, by thawing the pipe |
| Hob or gas fire will not light either | No gas reaching the house | You, then your gas supplier |
| Visible nest, debris or damage at the flue terminal | Flue exhaust or air intake obstructed | Gas Safe engineer |
| A10 returns in mild weather with gas working | Internal condensate trap, flue or another fault | Gas Safe engineer |
Safe checks before you reset
- Try another gas appliance, such as the hob. If nothing lights, check your prepayment credit or contact your gas supplier.
- Check the gas isolation valve on the pipe under the boiler. The handle should line up with the pipe, which means it is open.
- In freezing weather, follow the condensate pipe outside and look for ice. Thaw it with warm (not boiling) water or a hot water bottle. Our frozen condensate pipe guide shows where to pour and what to avoid.
- From outside, look at the flue terminal. If you see a nest, debris or damage, do not touch it. Note it for the engineer.
- Check the programmer and thermostat are calling for heat.
- Reset the boiler (see below). Give it a few minutes to try to light.
If you smell gas, do not reset the boiler or use electrical switches. Turn the gas off at the meter if it is safe to do so, open doors and windows, leave the property and call the National Gas Emergency Service on 0800 111 999.
How to reset A10 on an Easi-Heat i
Section 2.13 of the manual says to press and hold the reset key for more than two seconds, and the display shows "A10 Res" while the reset is available. If the correct operating conditions have been restored, the boiler starts up again by itself. The manual notes that with a remote control fitted, up to five consecutive unlock attempts are allowed, but we suggest you stop after two or three. If those attempts do not work, the manual's instruction is to contact Vokera's Technical Assistance Centre.
When to call a Gas Safe registered engineer
Call an engineer if A10 returns after two or three resets, if the gas supply and condensate pipe are both fine, or if you saw anything wrong with the flue. The engineer will usually check the condensate trap and pipe inside and outside, inspect the flue and air intake, measure the gas pressure at the boiler and look at the ignition and flame detection parts. If the condensate pipe freezes every winter, ask about upsizing, insulating or rerouting it in line with the 32 mm guidance above. For more on flue problems, see our boiler flue guide.
When you book, give the code, the model (Easi-Heat i 25C or 29C, shown on the front), whether other gas appliances work and whether the fault began in cold weather.
Do not remove the casing, disconnect the condensate trap or try to clear the flue yourself. Anything inside the boiler or on the flue must be handled by a Gas Safe registered engineer.
Typical repair costs in the UK
| Job | Typical UK cost |
|---|---|
| Thawing a frozen condensate pipe yourself | Free |
| Engineer call-out and diagnosis | Typically £60 to £150 |
| Condensate pipe reroute or insulate | Typically £80 to £200 |
| Flue repair or adjustment | Typically £150 to £400 |
| Minor repair (small part, sensor or wiring) | Typically £100 to £180 |
Other Vokera codes are listed on our Vokera fault code hub.