The most common Vokera boiler error codes include A01 for ignition failure, A04 for low water pressure, A03 for fan faults, and sensor issues like A07 or A09. At Eazy Heat we help many UK homeowners and landlords understand and resolve these faults quickly so they can get their heating and hot water back on.
Vokera Boiler Error Codes: A Quick Overview
Vokera boiler error codes provide a clear indication of what is wrong with your boiler so you can take the right action. Here is a quick overview of the most common codes you are likely to see on popular Vokera models.
| Error Code | What It Means |
| _St | Autostop for safety |
| _CL | Call for service |
| A01 | Ignition failure – flame not sensed |
| A02 | Limit thermostat fault – overheating |
| A03 | Fan fault |
| A04 | Low system water pressure |
| A06 | Domestic hot water thermistor fault |
| A07 | Primary flow thermistor fault – temperature too high |
| A08 | Return thermistor fault – temperature too high |
| A09 | Flue thermistor fault |
| A11 | False flame detection |
| A77 | Low temperature thermostat fault |
Vokera Boiler Error Codes: Causes & How to Fix
Understanding the causes behind each Vokera boiler error code helps you decide whether a simple reset will do or if you need professional help. Below we break down the most common codes with clear explanations and step by step fixes.
A01 Ignition Failure
Error code A01 on your Vokera boiler means the unit has tried to light the burner but cannot detect a flame. This safety lockout stops the boiler to prevent unburnt gas from building up.
The most common reasons are a problem with the gas supply, dirty or faulty ignition electrodes, or a blocked burner.
How to Fix
- Check that your gas supply is turned on at the meter and that other gas appliances like your hob work normally.
- If you have a prepay meter, top it up and confirm credit is showing.
- Press the reset button on the boiler once and listen for the ignition sequence.
- If the fault returns do not keep resetting.
- Call a Gas Safe registered engineer to inspect the ignition electrodes gas valve and burner.
- The engineer will clean or replace faulty parts and test gas pressure.
- They will reset the boiler and run full tests to confirm safe operation.
A04 Low System Water Pressure
Error code A04 on your Vokera boiler means the water pressure in the central heating system has dropped too low. The boiler locks out to protect the pump and heat exchanger from running dry.
This is one of the most common faults and is often caused by small leaks, natural pressure loss or recent bleeding of radiators without topping up.
How to Fix
- Check the pressure gauge on the front of the boiler. It should read between one and one point five bar when cold.
- Locate the filling loop, usually a flexible hose with valves underneath the boiler.
- Open the valves slowly while watching the gauge until it reaches one point two to one point five bar.
- Close the valves firmly and bleed any air from the radiators.
- Reset the boiler and test heating.
- Monitor the pressure over the next few days. A quick drop means a leak needs professional attention.
- The engineer will locate and repair any leaks then repressurise and test the system.
A03 Fan Fault
Error code A03 on your Vokera boiler means there is a problem with the fan that expels waste gases through the flue. The boiler locks out because it cannot confirm safe airflow.
Common causes include faulty fan motor blockages in the flue or wiring issues.
How to Fix
- Turn off the boiler power and allow it to cool.
- Check external flue and air intake terminals for visible debris but do not clear internal pipes yourself.
- Reset the boiler once and listen for the fan.
- If the fault returns, book a Gas Safe engineer.
- The engineer inspects the fan, cleans any blockages and replaces the fan if needed.
- They test fan speed and combustion quality.
- The engineer resets the boiler and confirms safe operation.
Persistent error codes on your Vokera boiler can lead to costly repairs over time and you might want to consider investing in a new boiler which will save you money in the long term. At Eazy Heat we see many homeowners and landlords reach this point and choose a modern efficient system for peace of mind.
Upgrade to a New Boiler with a 12-Year Warranty from Eazy Heat
If your Vokera boiler is displaying error codes more frequently or repair costs are starting to add up, it could be more cost-effective to replace it with a modern, energy-efficient boiler. At Eazy Heat, we make upgrading simple for homeowners and landlords across the UK with a fast, hassle-free installation service and transparent online pricing.
Every new boiler installation includes a market-leading 12-year parts and labour warranty, giving you long-term peace of mind and protection against unexpected repair costs. Our easy online quotation tool provides a fixed, no-obligation price in just a few minutes, so you’ll know exactly what your replacement will cost before booking.
Whether your current Vokera boiler is becoming unreliable or you’re looking to improve efficiency and reduce your energy bills, Eazy Heat can help you find the right boiler for your home. Get your online quote today and discover how straightforward replacing your boiler can be.
FAQs
How do I know if my Vokera boiler needs replacing rather than repairing?
If you have repeated faults or the boiler is over ten years old a new installation is often more cost effective in the long run.
Can I reset my Vokera boiler every time an error code appears?
Reset once after basic checks but repeated resets without fixing the cause can mask serious problems. Call an engineer for recurring faults.
Are Vokera boilers reliable for rental properties?
Vokera boilers are popular for their affordability but like all systems they need regular servicing. Landlords benefit from planned maintenance to minimise tenant call outs.
What is the average lifespan of a Vokera boiler?
With good maintenance most Vokera boilers last ten to fifteen years. Hard water areas or heavy use can shorten this.
Should I choose a Vokera boiler for my next installation?
Vokera offers good value but Eazy Heat can compare options across brands to find the best fit for your property and budget.