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Viessmann Boiler b2 Fault Code


The Viessmann fault code b2 relates to the fan and here we have Q & A or require an engineer for an emergency boiler repair.


The Viessmann Boiler Fault Code b2 Error Common Q & A


Just below, we have a list of common questions relating to the b2 fault code on the Viessmann Boiler.

Viessmann boiler error code b2
  • What does the B2 fault code mean on my Viessmann boiler?
  • If my boiler is showing the B2 fault code, can I fix it on a DIY basis?
  • If I reset the boiler, will this clear the fault code?
  • How will my boiler engineer test the electrics on my boiler?
  • What would have caused a problem with the electrics in my boiler?
  • How would boiler leaks occur on my boiler?
  • Why do leaks occur on the boiler’s heat exchanger?
  • Can limescale build-up be prevented?
  • How will my boiler engineer be able to diagnose a leaking heating pump?
  • If boiler vibrations have caused the issues on my Viessmann boiler, what could be the cause?
  • At what point should I consider a new boiler?

What does the B2 fault code mean on my Viessmann boiler


If you’ve noticed the B2 fault code being shown on the display panel of your boiler, the problem lies with your boiler’s internal electronics.

The fault code system is controlled by the main printed circuit board (PCB). If the PCB recognises a problem that might lead to the boiler operating dangerously, intermittently, or in a way that could cause damage to expensive boiler parts, it’s going to lockout.

The idea behind showing fault codes, is to try and pinpoint the problem. This means that when an engineer visits your property, they can diagnose and fix the problem quickly, keeping repair bills to a minimum.

If my boiler is showing the B2 fault code, can I fix it on a DIY basis


The B2 fault isn’t one that you should try to attempt to fix on DIY basis. The problem here is with the internal electronics. And to get to these electronics, you’d have to take the boiler to pieces. Taking boilers apart is a job that should be reserved for those with the appropriate skills and experience.

What you need to do, is contact and emergency boiler repair company. They’ll have multiple Gas Safe engineers that are qualified to fix your boiler.

If I reset the boiler, will this clear the fault code


Each modern boiler has a reset function built in to the appliance. But, this isn’t designed to fix fault codes on boilers. Instead, the reset function is only designed to be used once the problem has been found and fixed by your engineer.

Resetting your boiler without fixing the issue at hand won’t achieve anything. All it might achieve, is the boiler firing into life for less than a minute before it locks out again. And in some scenarios, this one minute of running time, could cause further damage to expensive components.

How will my boiler engineer test the electrics on my boiler


Knowing this is an internal electrical fault, your boiler engineer will need to test wiring, connections and components to determine what’s causing the problem.

They’ll be able to run a quick visual inspection to see if there’s anything obvious that could be causing problems. However, it’s more likely they’ll be able to diagnose the root cause of the problem, by using a multi-meter. Testing each wire, connection and component individually, they’ll be able to determine what’s working, and what’s not.

Once the faulty parts of been found, they can be fixed. After doing so, your boiler engineer can reset your appliance to clear the B2 fault code from the display panel.

What would have caused a problem with the electrics in my boiler


Although you may want to jump straight in and fix any problems with your electrics, there’s another thing that you need to consider; what caused the fault to occur in the first place.

Old age is a common killer of boilers, but it’s not the only reason that boilers fail. If there are problems with the electrics in your boiler that aren’t related to old age, we’d be looking towards:

  • Boiler leaks
  • Excessive boiler vibrations

Both things can cause extensive damage to the internal electronics on boilers.

How would boiler leaks occur on my boiler


There are two common types of boiler leaks that occur on modern boilers. And, they come from either the heat exchanger, or the boiler’s pump.

When a leak occurs, it’s not necessarily going to mean that your boiler stops working. But what it does mean, is that over time moisture is going to find its way into electrical components. This is especially the case if you own an older boiler, as the electrical components aren’t as well sealed as they are on newer appliances.

So, after determining what electrical damage has been caused, your boiler engineer needs to fix the leak.

Why do leaks occur on the boiler’s heat exchanger


If the leak is coming from your heat exchanger, it’s rarely good news. And, that’s because leaks on this component tend to come from cracks. It’s rare that these can be fixed and that’s going to mean that the heat exchanger needs to be replaced to stop the leak; costing around £400-500.

But, what caused the heat exchanger to crack? Assuming again, old age isn’t the cause, the problem could be due to limescale build-up.

When limescale builds up on the heat exchanger, it’s going to cause a hot spot; this part of the heat exchanger burns hotter than the rest. This weakens a small section of the heat exchanger and eventually, that’s going to lead to a crack.

Can limescale build-up be prevented


Prevention is always better than cure. If your boiler engineer suspects that limescale is a problem but has not yet caused a fault or leak, you’ll want to fit a limescale reducing filter. This is going to catch limescale before it has a chance to settle on expensive components such as the heat exchanger.

How will my boiler engineer be able to diagnose a leaking heating pump


Another common place that leaks occur, is on the heating pump. Typically, your boiler engineer will expect to see the seals leaking. This could be due to old age, or a blockage.

Most manufacturers of quality heating pumps have service kits available, which will include pump seals.

However, not all pumps can be salvaged. If you need a replacement heating pump, you should expect to pay around £250.

If boiler vibrations have caused the issues on my Viessmann boiler, what could be the cause


Naturally, your boiler is going to vibrate a little. However, excessive vibrations can be caused by worn parts. And, these excessive vibrations can cause damage to fragile electrical components.

If you’ve noticed that your boiler is louder than usual, your boiler engineer will want to check components such as the fan and heating pump, to check they’re not blocked or excessively worn. After all, if one electrical fault has occurred due to these vibrations, it’s likely others will develop over time if the problem isn’t fixed.

If either of these components are the offender, it’s likely that the bearings are the cause of the issue. Worn bearings are going to lead to the component failing to run smoothly, grinding on the shaft, and that’s what could be creating both noise, and vibrations.

At what point should I consider a new boiler


It’s likely that the problems causing the B2 error code to be displayed can be fixed. It could be something as simple as securing a loose connection, replacing a section of damaged wiring, or a small electrical component. And to ensure it doesn’t happen again, it might mean completing a small component repair, such as replacing pump seals, so leaks don’t cause damage.

Typically, we’d not expect to look at replacing a boiler until repair costs exceed £500. And even then, if the boiler is in warranty, it’s likely the manufacturer will cover all or some of the repair costs.

Other Viessmann boiler issues


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