Potterton Boiler E84 Fault Code


The Potterton fault code E84 thermostat or timer issue Q & A or require an engineer for an emergency boiler repair.


The Potterton Boiler Fault Code E84 Error Common Q & A


Just below, we have a list of common questions relating to the E84 fault code on the Potterton boiler.

Potterton Boiler E84 Fault Code

  • What does the E84 fault code mean on my Potterton boiler?
  • If my boiler stops working due to the E84 fault code, is it dangerous?
  • Can I reset the boiler to clear the E84 fault code?
  • What problems can lead to the E84 fault code being displayed on my Potterton boiler?
  • How will my boiler repair engineer be able to check that the thermostat is working, and that it is compatible with my boiler?
  • If my boiler controls are faulty, how will my repair engineer know?
  • How much will it cost to fit a new thermostat on my Potterton boiler?
  • My boiler engineer thinks it’s the wiring and connections causing the issues, can they be fixed?
  • What can cause damage to wiring and connections in my boiler?
  • Could device pairing be the issue here?
  • I’ve re-paired my thermostat, but it still turns my boiler on and off randomly, what’s the problem?
  • My boiler engineer thinks the PCB needs replacing, could this be right?
  • Is there a way to double check that the PCB is to blame?
  • My PCB needs replacing, how much is this going to cost?

What does the E84 fault code mean on my Potterton boiler


If your boiler is showing the E84 fault code on the display panel, there’s a problem with the room thermostat or timer.

It might be that your boiler, instead of showing the E84 fault code, is showing E85, E86 or E87.

If my boiler stops working due to the E84 fault code, is it dangerous


It’s usually just gas related faults that we consider to be dangerous. Here, the problem is a simple lack of communication between the room controller and the boiler; it’s unlikely to be dangerous.

Can I reset the boiler to clear the E84 fault code


Unfortunately, a reset isn’t going to fix the problem. The reset function on your Potterton boiler is designed to clear a fault code after the problem has been fixed, it’s not a way to physically fix a boiler.

The best thing you can do, is call a Gas Safe boiler engineer. They’ll be able to diagnose the problem and fix it. Once they’ve done so, they can reset your boiler on your behalf, which will clear the fault code from the display panel.

What problems can lead to the E84 fault code being displayed on my Potterton boiler


It’s likely that your boiler is suffering from one of the following problems:

  • The thermostat has been installed incorrectly, or isn’t compatible with your boiler
  • The thermostat or timer is faulty, and needs replacing
  • The connections and wires to/from the thermostat and timer are loose or damaged
  • The thermostat hasn’t been paired with the boiler, or there’s an interruption with the signal

How will my boiler repair engineer be able to check that the thermostat is working, and that it is compatible with my boiler


The first thing you should explain to your engineer, is whether the thermostat or boiler timer are new. If they are, there’s a good chance that a unit that isn’t compatible with your boiler has been fitted.

For example, Salus Controls make a range of thermostats for different boilers. And, many of their products are generic, fitting a wide range of boilers.

On the flip-side, they have products like the ST620WBC. This unit is designed specifically to fit Worcester Bosch boilers. If you have this fitted on a branded boiler that isn’t Worcester Bosch, that’s going to be the cause of your problem.

Manufacturers that produce boiler controls usually have lists of either, which boilers their controls work with, or which ones they won’t work with. And, these lists are going to be the first point of call for your emergency boiler engineer.

If my boiler controls are faulty, how will my repair engineer know


If compatibility isn’t a problem, the next step is to check that the controls aren’t faulty. Faulty boiler controls are going to lead to intermittent operation, or no functionality at all.

Thermostats can develop faults over time. So, if your boiler and thermostat are particularly old, it’s likely the thermostat is the problem.

An emergency electrician and boiler repair specialist will be able to test the thermostat using a multi-meter. This determines if the thermostat is getting power. And, if it’s not, a replacement thermostat is going to need to be fitted, to fix the problem.

How much will it cost to fit a new thermostat on my Potterton boiler


The costs associated with thermostat installation are split into three sections:

  • Fitting
  • Setup
  • Cost of stat

The time taken to fit thermostats, tends to be stable. However, the complexity of the setup and syncing with the boiler can vary, and this means that the installation cost can vary too.

You can pick up basic but cheap thermostats from Salus, Honeywell and Siemens, for less than £30. On the flip-side, you can spend up to £200 on smart thermostats from brands such as Nest and Hive Heating.

My boiler engineer thinks it’s the wiring and connections causing the issues, can they be fixed


If there’s a problem with any electronic device on your boiler, it makes sense to check the wiring and connections. If either are loose or damaged, that’s going to lead to intermittent signals to the printed circuit board (PCB). In turn, that’s going to mean that your boiler doesn’t operate in the way it should.

Typically, minor damage can be fixed, as can loose connections. However, when there’s major damage to wiring and connections, it makes sense to replace those connections and sections of wiring.

What can cause damage to wiring and connections in my boiler


If the wiring and/or connections have become loose, this is likely to be a simple case of boiler vibrations. Boilers vibrate, and over time that can lead to parts, wiring and connections working their way loose. It’s nothing to worry about and can be fixed.

That is unless, you’ve noticed excessive boiler vibrations as of late. This could be a sign that the fan or pump is failing. The quicker that problem is found and fixed, the reduced likelihood of an expensive repair bill.

However, when it’s physical damage to connections that’s the problem, the culprit is usually water damage. If you suspect water damage, you have a leak. And, it’s important that this leak is fixed as soon as possible.

Water damage is a killer of modern boilers. Left untreated, it can cause damage that costs upwards of £500 to repair.

Could device pairing be the issue here


A lot of boiler control manufacturers now produce wireless radio frequency (RF) thermostats. The main benefit of them is the fact that they’re portable, rather a typical thermostat that is wired into the wall.

If you check your owner’s manual, there should be a section on how to reset and re-pair your thermostat with your boiler. This reset might be enough to regain the connection and clear the E84 fault code on your Potterton boiler.

I’ve re-paired my thermostat, but it still turns my boiler on and off randomly, what’s the problem


Although wireless and RF thermostats have plenty of benefits, they do have downfalls. For instance, if you have a neighbour using the same thermostat, on the same radio channel, they’ll be able to control your boiler.

So, when they turn on your boiler, they’ll be turning on your boiler as well. If you’re having problems with your boiler coming on at random, check which thermostats and channels your neighbours are using.

Once you know what channels they’re using, refer to your owner’s manual. This will usually have a section on how to change the channel of an RF thermostat.

My boiler engineer thinks the PCB needs replacing, could this be right


It’s most likely that the E84 fault code is related to a thermostat issue. However, any electrical fault on a boiler can be linked to the PCB. The PCB is the unit that controls all electronic devices, it even highlights and displays fault codes on your boiler. If this unit fails, or provides intermittent signals to other electronic components, it’s going to cause a whole host of boiler problems.

Is there a way to double check that the PCB is to blame


PCB units are extremely expensive to replace. So, you’ll want to be 100% certain that it’s failed, before changing it over.

The thing to do here, is to check the circuit board, wiring and connections for damage. Then, the engineer will need to test each wire and connection using a PCB. This will determine that all wires and connections have power, so the PCB should have too.

Next, they’ll test the PCB itself. If this doesn’t have power, it’s going to need replacing.

My PCB needs replacing, how much is this going to cost


A typical PCB replacement starts at £350, rising to around £500 for some boiler models. That includes parts and labour.

But, you shouldn’t dive right in and replace it. You’ll want to get your boiler engineer to assess the overall condition of your boiler. This means checking over parts like the gas valve, pump and fan. If your boiler is old, it’s likely these parts are on their way out too. And, that’s going to mean more expensive repair bills soon. At this point, it might be worth weighing up your options by getting a quote for a new boiler.

Other Potterton boiler issues


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