When resetting a Vokera boiler helps, and when it does not
A reset tells the boiler to try again after it has locked itself out. Vokera's Compact A and Unica i manuals say that when a fault code is displayed the appliance "will require to be reset manually", and both tell you to check the fault code table for the required action first. That order matters. A reset helps when the cause has already gone away or you have fixed it, such as gas restored, pressure topped up or a frozen condensate pipe thawed. It does not help when a part has failed, and repeated resets on a boiler that keeps locking out can hide a fault that needs attention.
Do not reset at all if you smell gas. Turn the gas off at the meter if it is safe to do so, open the windows, leave the property and call the National Gas Emergency Service on 0800 111 999.
Where the reset is on your Vokera
Vokera uses two different methods depending on the model: a reset position on the mode selector knob, or a dedicated reset key.
| Model | Reset method in the Vokera manual |
|---|---|
| Compact 25A, 29A | Wait two minutes, then turn the mode selector knob across the reset position |
| Unica i28, i32, i36 | Wait two minutes, then rotate the mode selector knob across the reset position |
| Easi-Heat i 25C, 29C | Press and hold the RESET key for more than two seconds |
| Vision, Linea, Mynute, Evolve and others | Check the controls section of your own user instructions |
On the Compact A and Unica i, the mode selector is the main knob on the control panel. It also has an OFF or standby position, where the display shows "- -", plus hot water only and heating with hot water settings. The reset mark sits on the same dial. Vokera publishes user instructions for its other ranges on its website, and the model name is printed on the front of the boiler. We have not set out the method for models whose manuals we have not checked.
Step-by-step: resetting a Vokera boiler
- Write down the code exactly as it appears, along with any symbol lit on the display.
- Look the code up in your manual or in the table below, and deal with the cause if it is one you can safely fix.
- On a Compact A or Unica i, wait two minutes. The Unica i manual says a boiler that has failed to light needs at least two minutes before resetting.
- Reset: turn the mode selector across the reset position and back to your normal setting, or hold the RESET key on an Easi-Heat i for more than two seconds. The Easi-Heat i display shows "A10 Res" when a flame lockout can be reset.
- Give the boiler a few minutes to run through its start-up.
- If the code comes back, stop after two or three attempts in total.
The Compact A and Unica i manuals both say that if the boiler needs frequent resetting, it may have a fault and you should contact your installer or Vokera. The Easi-Heat i manual tells you to contact Vokera's Technical Assistance Centre if reset attempts do not work. Our general guide on how to reset a boiler covers other brands.
Vokera display symbols and what they mean
The Compact A and Unica i displays use a set of symbols alongside the code. The manuals list:
- Heating and hot water symbols: that mode is active.
- Frost protection symbol: the frost function is running.
- Fault or alarm symbol: a fault has been detected.
- Low system pressure symbol: the pressure is too low.
- Ignition fault symbol: the boiler failed to light.
- External sensor symbol: an outside temperature sensor is connected.
- P: hot water pre-heat is enabled. It flashes while it is working and is not a fault.
Two other messages are not resettable faults: "_St" (autostop) and "_CL" (call for service). Both manuals say to call an engineer for these, or your landlord if you rent.
Read the error code first
The Compact A manual says codes A01 to A04 need a manual reset, while A06 to A09 are temporary and may clear without action. Here are the common ones from the Compact A and Unica i tables, with the Easi-Heat i's newer equivalents:
| Code | Meaning | What to do |
|---|---|---|
| A01 | Ignition failure | Check gas, then reset once or twice at most; engineer if it returns |
| A02 | Limit thermostat fault | Check pressure, reset once; engineer if it returns |
| A03 | Fan tacho signal fault | Reset once or twice at most; engineer if it returns |
| A04 | Insufficient system water pressure | Top up to 1 to 1.5 bar, then reset |
| A07 | Primary (flow) thermistor fault or over-temperature | Engineer if it persists |
| A09 | Flue thermistor fault | Reset once or twice at most; engineer if it returns |
| A11 | False flame | Reset once or twice at most; engineer if it returns |
| A10, A20, A30, A40 | Easi-Heat i: flame lockout, limit thermostat, fan fault, fill the system | As above for the matching older code |
Some limit thermostats have their own reset inside the casing. That is engineer-only work. Never remove the casing to reset a thermostat or reach any part inside the boiler.
Some newer Vokera ranges use a different code list altogether, so if your code is not here, check your own manual. For pressure codes see Vokera A04, and for ignition faults see Vokera A01.
If it will not reset, and whether to switch it off and on
If the boiler locks out again straight away, work through the outside causes before trying again:
- Gas: check another gas appliance and any prepayment credit, and that the gas isolation valve under the boiler is open, with its handle in line with the pipe.
- Pressure: Vokera's manuals ask for 1 to 1.5 bar with the boiler off and cold. The Compact A and Unica i give 0.5 bar as the minimum, and the Easi-Heat i shows A41 and then A40 below 0.3 bar. Our Vokera boiler pressure guide explains how to top up.
- Power: check the fused spur is on and the display is lit.
- Frozen condensate pipe: in a frost, thaw the outside pipe with warm (not boiling) water or a hot water bottle.
Switching the boiler off at the fused spur and back on is sometimes suggested as a reset. The Vokera manuals we checked describe the knob or the RESET key, not a power cycle, as the way to clear a lockout. Switching off also stops the built-in frost protection, which the manuals say needs a permanent electrical supply. If you do switch off, for example to check the display comes back after a power cut, turn it back on promptly and then use the proper reset method.
When to call a Gas Safe engineer, and repair or replace
Call a Gas Safe registered engineer if a code returns after two or three resets, if the boiler needs resetting every few days, or for any code linked to the ignition, fan, flue sensor or limit thermostat. Give them the code, the model name and what you have already checked. Vokera's manuals ask you to have your address, postcode and the appliance log book ready when you report a fault.
| Job | Typical UK cost |
|---|---|
| Engineer call-out and diagnosis | Typically £60 to £150 |
| Ignition electrode | Typically £90 to £180 |
| Fan replacement | Typically £200 to £400 |
| PCB replacement, fitted | Typically £250 to £550 |
A single part on a sound boiler is usually worth repairing. If an older Compact or Unica needs a fan and a board in the same year, or keeps locking out after repairs, it is worth asking the engineer for a replacement quote as well, so you can compare the two honestly.