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Vokera Boiler A06 Fault Code

The Vokera fault code A06 boiler DHW thermistor Q & A or require an engineer for an emergency boiler repair.


The Vokera Boiler Fault Code A06 Error Common Q&A

Just below, we have a list of common questions relating to the A06 fault code on the Vokera boiler.

Vokera Boiler A06 Fault Code Error
  • Why is my Vokera boiler showing the A06 fault code?
  • What does the DHW thermistor do on my Vokera boiler?
  • Can I reset my boiler to clear the A06 fault code?
  • What could cause the DHW thermistor issue and the A06 fault code to be displayed?
  • Is there a DIY fix to clear the A06 fault code on my Vokera boiler?
  • How will my boiler engineer know if it’s the wiring and connections causing the problem?
  • My DHW sensor has already been replaced, what else could be causing the A06 fault code to be displayed?
  • What is the PCB on my boiler?
  • How can a boiler engineer check to see if the PCB is causing the A06 fault code to be displayed?
  • What else will help determine if the PCB is to blame for the A06 fault code?
  • Can the PCB on my Vokera boiler be fixed?
  • If I need to replace my PCB, how much is it likely to cost?

Why is my Vokera boiler showing the A06 fault code

Your boiler is designed to show fault codes when a problem occurs. This helps to determine what the fault is so an engineer can get it fixed.

For dangerous faults, the boiler will lock out completely.

In the case of the A06 fault code, it relates to an issue with the DHW thermistor on your Vokera boiler.

What does the DHW thermistor do on my Vokera boiler

Boilers have a range of thermistors. These are temperature sensors. They ensure that the appliance is working correctly, and they feed back their findings to the printed circuit board (PCB).

Thermistors don’t read in actual temperature. The readings they produce are resistance (ohms). It’s the PCB that converts these resistance readings in ohms, into a temperature.

If the temperature is too high, too low or there is no reading at all, a fault code will be displayed.

The DHW thermistor is monitoring temperature on your domestic hot water.

Can I reset my boiler to clear the A06 fault code

Sometimes there are intermittent faults with boilers whereby there’s not a physical issue, but a sensing issue instead. So, clearing it is as easy as resetting the boiler.

However, this isn’t advisable. Even if this does clear the fault code, there’s a problem at hand that needs to be fixed.

Our advice would be to phone a Gas Safe engineer and ensure they diagnose and fix the problem.

Once they’ve done this, they’ll rest the boiler to clear the fault code for you.

What could cause the DHW thermistor issue and the A06 fault code to be displayed

The most probable cause of the A06 fault code is a faulty DHW sensor. Luckily, these are not particularly expensive to replace.

The actual part itself (depending on the model of your boiler) should be in the region of £20. You should then budget 1-2 hours for a Gas Safe engineer to fit the DHW sensor on your boiler.

In total, the replacement sensor shouldn’t cost more than £100, and won’t take more than a few hours.

Is there a DIY fix to clear the A06 fault code on my Vokera boiler

There’s not a DIY fix, simply because working on a gas appliance is only something that Gas Safe engineer should be doing.

However, there’s potentially a quicker and cheaper fix than replacing the DHW sensor.

Boilers vibrate, and older ones vibrate much more than newer ones. As they do, connections and sections of wiring can work their way loose.

There’s a good chance that the DHW isn’t at fault, but instead, it’s a case of loose wiring and connections.

In fact, the boiler engineer will need to check this isn’t the case first.

If they don’t, there’s a chance that a replacement DHW sensor won’t fix the problem because the wiring/connections still aren’t sufficiently connected.

How will my boiler engineer know if it’s the wiring and connections causing the problem

The first step is a quick visual inspection. If the A06 fault code keeps coming on and off, the connection/wiring issue is likely minor, and that’s going to make it hard to spot.

However, if the A06 fault code has stayed on since it originally appeared and loose connections and wiring issues are to blame, they’re likely to be obvious.

If the engineer can find the loose or damaged connections with a visual inspection, they’ll be able to fix and re-secure them.

Whereby the engineer can’t physically see the loose or damaged connections, they’ll be able to test the system using a multi-meter.

A multi-meter highlights what the eye can’t see. It will be able to pick up on any sections of wiring (or connections) that are causing the issues.

My DHW sensor has already been replaced, what else could be causing the A06 fault code to be displayed

Fault code systems on boilers (especially older ones) are not particularly complex. So, whilst they try to highlight the exact fault, they’re not 100% accurate.

One thing that you’ll want to test, is that it’s not the printed circuit board (PCB) that’s causing the issue on your boiler.

What is the PCB on my boiler

The PCB is the heart of your boiler. It houses the control panel, but it is also connected to all the electronic components in your boiler.

This includes components such as the:

  • Gas valve
  • Pump
  • Fan

And of course, it’s also connected to the DHW sensor.

Depending on the specific component, signals are given and received by the PCB. The PCB manages when each component turns on and off. This is partly based on the readings it receives from sensors (such as the DHW sensor).

So, it makes sense that if the PCB is faulty, it won’t be giving and receiving the correct readings.

When this is the case, not only will the boiler start to work intermittently, the readings it gets from sensors (such as the DHW sensor) are likely to be incorrect.

How can a boiler engineer check to see if the PCB is causing the A06 fault code to be displayed

Just as they did with the DHW sensor, the boiler engineer will be able to test the PCB with a multi-meter.

The first thing to do is to check the PCB is getting power. To do this they’ll check the LED indicators on the control panel, and then test all wiring and connections to the PCB.

If the readings on the PCB are inconsistent, it’s likely that this is the fault.

What else will help determine if the PCB is to blame for the A06 fault code

As the PCB is likely to be receiving and giving the wrong signals when it’s faulty, a boiler will work intermittently.

It might:

  • Not heat radiators up fully
  • Produce hot water that goes hot then cold
  • Turn off and on randomly
  • Not respond to demand from the thermostat

Anything unusual in comparison to normal operation is potentially a sign that the PCB is faulty.

Can the PCB on my Vokera boiler be fixed

The PCB can be fixed if the problem stems from loose or damaged connections. This is usually a quick and easy fix.

However, beyond this, there’s little that can be done to fix a PCB and it will need to be replaced.

If I need to replace my PCB, how much is it likely to cost

Replacing a PCB is something that shouldn’t be done without consulting an engineer. The replacement cost of a PCB can be upwards of £450 for some boilers.

And, if the PCB is faulty, there’s a good chance that other parts in the boiler are likely on their last legs too.

Get a boiler engineer to inspect each expensive component in the boiler. If they’re sure that these components are in reasonable condition, the most cost-effective solution is a PCB replacement.

If these components are showing signs of excessive wear, the wise option would be to invest the money that would’ve gone towards a PCB replacement, on a boiler replacement instead.

Other Vokera boiler issues

For more boiler issues regarding the Vokera then please visit the Vokera Boiler Problems And Cures page.