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Potterton Boiler E83 Fault Code


The Potterton fault code E83 room controller Q & A or require an engineer for an emergency boiler repair.


The Potterton Boiler Fault Code E83 Error Common Q & A


Just below, we have a list of common questions relating to the E83 fault code on the Potterton boiler.

Potterton Boiler E83 Fault Code
  • What does the E40 fault code mean on my Potterton boiler?
  • What does the NTC return thermistor do on my Potterton boiler?
  • If I reset my boiler, will this fix the return NTC thermistor problem?
  • What could be the cause of the E40 fault code being displayed on my boiler?
  • How will the emergency boiler engineer know if it’s the NTC thermistor that’s to blame?
  • The thermistor isn’t the problem, so, what’s next?
  • How can air locks contribute to a circulation fault?
  • Are air locks easy to remove?
  • Why would the pump fail on my Potterton boiler?
  • What’s the most probable cause of a blockage in a heating system?
  • How can sludge be removed, and the E40 fault code cleared?
  • What can be done to stop heating sludge causing a problem in the future?
  • How can low water pressure contribute to poor circulation, and the E40 fault code being displayed?
  • What does the heat exchanger have to do with the E40 fault code on my Potterton boiler?

What does the E40 fault code mean on my Potterton boiler


According to Potterton, the E40 fault code means that there’s a problem with the NTC thermistor for heating on the return side of the boiler.

What does the NTC return thermistor do on my Potterton boiler


Your boiler has NTC thermistors on both the flow, and the return pipes. When hot water is heated, it leaves the boiler via the flow. And, after travelling around the heating system, ready to be re-heated, it enters the boiler via the return pipe.

On each pipe, there is a thermistor. These thermistors monitor resistance. As heat goes up, resistance goes down (typically, around 12k ohms when at 20 degrees). The readings are passed to the printed circuit board (PCB), which converts them to a temperatures.

This allows the PCB to monitor temperature on the flow and return effectively, knowing when water is up to temperature, or when there’s a problem due to the water being too hot/too cold.

If I reset my boiler, will this fix the return NTC thermistor problem


Resetting your boiler won’t fix the problem at hand. Boiler resets are only designed to be used when an appliance has been fixed, it’s not a way to fix a boiler. On many occasions, resetting a boiler could lead to the appliance operating dangerously, or causing further damage to internal components.

The best thing to do, is to call an emergency boiler repair engineer. Once they’ve figured out and fixed the problem, resetting the boiler will clear the fault code.

What could be the cause of the E40 fault code being displayed on my boiler


Although this might seem like a specific fault code, there are plenty of potential problems. Those relating directly to the NTC thermistor include:

  • A short circuit on the thermistor
  • Wiring issues between the thermistor and the PCB
  • Faulty NTC thermistor

But, if this is a water temperature issue, rather than an NTC thermistor fault, the problem could stem from:

  • Airlocks in the heating system
  • Pump failure
  • Heating blockage
  • Low water pressure
  • Poor thermal output from the heat exchanger

How will the emergency boiler engineer know if it’s the NTC thermistor that’s to blame


Although the E40 fault relates directly to the E40, that’s not always the case. Fault code systems on boilers aren’t perfect, so it could just as well be something relating to low return water temperature, rather than a fault with the thermistor.

However, your engineer will be able to test all wiring, connections and the thermistor, to check it’s not the root cause of the problem.

Starting with a visual inspection, they’ll check for loose and damaged connections. If they seem in good condition and secure, they can then test the thermistor using a multi-meter. If the readings are showing low or no power, the thermistor will need to be replaced to clear the E40 fault code.

The thermistor isn’t the problem, so, what’s next


If the thermistor as well as its wiring and connections aren’t causing problems, it’s likely the return pipe water temperature is too low. And, that’s going to mean that the issue stems from either a heating element, or a water circulation fault.

How can air locks contribute to a circulation fault


The first and one of the easiest places to start, is looking for air locks. Air locks in heating systems can cause a whole host of problems, including:

  • Radiators not getting to temperature
  • The boiler cycling on and off
  • Hot water temperature being intermittent

Airlocks can build up in plenty of places throughout the heating system, including:

  • Towel rails
  • Radiators
  • The heating pump

Are air locks easy to remove


Air locks can be removed from towel rails and radiators, using a bleed key. As the valve opens, it will make a hissing noise; this is air being released. Once the hissing stops, that’s a sign that there’s no more air present. The same goes for the heating pump. But, the pump has a bleed screw, rather than a valve on it.

Why would the pump fail on my Potterton boiler


Without an operational pump, your heating and hot water isn’t going to get to temperature as it should.

The first thing to check here, is that the pump is getting power. Like all electrical components, your emergency repair company can test the component using a multi-meter. If wires and connections are secure, but the pump isn’t showing power, it’s going to need to be replaced.

If you need a boiler pump replacement, expect the cost to be in the region of £250.

Next, they’ll want to check the speed setting on the pump. Newer pumps tend to have 3 speed settings. If the setting has been knocked, changed, or not set correctly from the manufacturer, that’s going to cause heating water to travel too slowly, losing too much temperature by the time it reaches the return pipe.

Assuming wiring, connections and power are good, and the speed setting is correct, your engineer will want to check that there’s not a blockage in the pump or heating system.

What’s the most probable cause of a blockage in a heating system


Central heating sludge is most likely the culprit. This is a mixture of limescale, and iron oxide (rust from the inside of radiators, for instance), and it’s a common killer of heating systems.

Sludge will slowly settle inside radiators, towel rails, and even block up the pump. When it does this, circulation is affected, and that’s going to mean that the pump must work overtime, and still isn’t able to deliver the flow rate that it needs to.

How can sludge be removed, and the E40 fault code cleared


The first thing a heating engineer will need to do, is a hot flush; this gets rid of most heating sludge. A power flush is a more intense option, but not advisable for older heating systems, as there’s a good chance it could cause leaks.

What can be done to stop heating sludge causing a problem in the future


Most boiler replacement companies will now install preventative measures that combat limescale and heating sludge build-up.

After flushing out the system, it needs to be dosed with the correct levels of inhibitor. It’s this inhibitor that breaks down the sludge into small particles.

Once broken down into small particles, they can be caught by a magnetic system filter. Top brands include the likes of BoilerMag, Fernox and MagnaClean.

And, if you’re in a hard water area, there’s an additional preventative measure available; a limescale reducer. This is a filter that’s specifically designed to catch limescale and is installed alongside the boiler filter.

How can low water pressure contribute to poor circulation, and the E40 fault code being displayed


Your boiler works best at around 1.3 bar (always check your owner’s manual). Once it drops below 0.6 bar, it will usually lock out and display a fault code.

If your boiler isn’t set between 1 bar to 1.5 bar, it’s likely that circulation is being affected. You can top up your boiler pressure using the external filling loop. However, if your boiler is constantly losing pressure, it’s likely that there’s a leak.

You’ll want to find and fix that leak, before topping up the pressure. Topping up the pressure is done by allowing more water into the heating system. If you have a leak, it’s likely this leak is causing damage, which you are fuelling by adding more water in the system.

What does the heat exchanger have to do with the E40 fault code on my Potterton boiler


Finally, we have the heat exchanger. It’s the heat exchanger that heats water in your boiler. If it’s not working to its full potential, there’s a chance that flow temperature is already low. By the time water reaches the return thermistor, it’s so low that the boiler locks out.

If your boiler repair specialist suspects the heat exchanger is the problem, they’ll need to inspect it for cracks and limescale build-up. Limescale can usually be removed, but in the case of cracks, it’s likely it will need to be replaced.

Other Potterton boiler issues


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