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Intergas Boiler Fault Code 4


The Intergas fault code 4 relates to flame failure and here we have Q & A. We could also offer you a service by you clicking on our emergency boiler repair booking.


The Intergas Boiler Fault Code 4 Error Common Q & A


Just below, we have a list of common questions relating to the fault code 4 on the Intergas Boiler.

Intergas boiler error code 4
  • What does fault code 4 mean on my Intergas boiler?
  • My boiler won’t turn on after showing fault code 4, should I reset it?
  • What is the most likely cause of fault code 4 on Intergas boilers?
  • If the flame sensor isn’t the problem, what should my engineer check next?
  • How could the gas valve contribute to fault code 4 being displayed on my control panel?
  • If my gas valve is stuck, can it be fixed?
  • My Gas Safe engineer thinks I need a new gas valve, how much is this going to cost?
  • How could the burner cause fault code 4 to be displayed on the control panel?
  • What does the PCB do on my Intergas boiler?
  • How could the PCB contribute to fault code 4 being displayed on my boiler’s control panel?
  • How much will a new PCB cost in my Intergas boiler?

What does fault code 4 mean on my Intergas boiler


When your Intergas boiler develops a problem, it will display a fault code. This helps your boiler repair company to quickly diagnose the problem, reducing the overall cost of repairs.

In the case of fault code 4, the printed circuit board isn’t recognising that there’s a flame signal.

My boiler won’t turn on after showing fault code 4, should I reset it


After a fault code has been displayed, your boiler is going to lockout. For some faults, this is to preserve boiler components from further damage.

However, in the case of fault code 4, it’s more likely your boiler has locked out as a safety precaution. As there’s no flame signal, the boiler’s PCB can’t be sure if the boiler is operating safely.

For this reason, you shouldn’t attempt to reset your boiler. The reset function isn’t a way to fix a boiler.

Instead, you should call a Gas Safe registered engineer immediately. They’ll be able to advise on what the problem is, fix it, and then they’ll reset your boiler to clear the fault code from the display panel.

What is the most likely cause of fault code 4 on Intergas boilers


The first thing your boiler repair company will want to check, is the condition of the flame sensor. The flame sensor feeds back signals to the PCB to tell it when a flame is present. If a flame isn’t present when it should be, the PCB recognises there’s a problem and locks out.

However, if the flame sensor is faulty, it could be telling the boiler’s PCB there is no flame present, even when there is.

Your boiler engineer will need to check the flame sensor for power, ensuring it’s communicating correctly with the PCB. If it’s not, it’s going to need to be replaced to fix the problem.

If the flame sensor isn’t the problem, what should my engineer check next


After ensuring that the flame sensor isn’t causing issues, your engineer will likely check the:

  • Gas valve
  • Burner
  • PCB

It’s likely that the flame sensor isn’t the problem, if your boiler engineer can visibly see a pilot light, and then the boiler locks out. That’s a sure sign that a flame is present, and the flame sensor isn’t passing on the signal to the PCB.

How could the gas valve contribute to fault code 4 being displayed on my control panel


When the flame sensor isn’t the issue with your Intergas boiler, the first component to check is the gas valve. It’s the gas valve that controls the flow of gas into the burner. A faulty gas valve may not be providing the burner with the gas it needs to create and maintain a flame in your boiler.

Gas valves are mechanical parts that can wear over time. As they wear, they can get stuck. This could be partially open, or partially closed. But, as fault code 4 on Intergas boilers relates to a lack of flame, it’s most likely that the gas valve is stuck fully or partially closed.

If my gas valve is stuck, can it be fixed


Your boiler engineer will assess the overall condition of your gas valve. If the condition is good, they’ll attempt to free the valve, so it’s able to provide the burner with the correct levels of gas.

However, this isn’t always possible. Or, the gas valve, even when freed, may get stuck again. If your boiler engineer suspects that the gas valve is going to get stuck again, they’ll replace it. It doesn’t make sense to spend time and money on labour, not to replace a part that is likely to fail again.

My Gas Safe engineer thinks I need a new gas valve, how much is this going to cost


Gas valve replacement costs will vary, depending on the exact Intergas boiler that you own. However, typical replacement costs are likely to be in the region of £300, including parts and labour.

The job of replacing the old gas valve is likely to take around one working day, assuming your engineer has direct access to parts from their local suppliers. Most suppliers will need to order in the gas valve on next day delivery, meaning it could be 2-3 days until your boiler is up and running again.

How could the burner cause fault code 4 to be displayed on the control panel


After checking the flame sensor and gas valve, the next step is to assess the condition of the burner in your appliance.

The burner is what enables the boiler to create and establish a flame. For particularly old boilers that don’t have a burner that’s efficient, it’s likely there’s lots of carbon build-up. This further reduces efficiency, and in extreme cases, the burner can’t maintain a flame.

Sometimes, they can be cleaned to a point where a flame can be maintained. But a replacement may be needed for boilers that have a burner in extremely poor condition. Typically, a burner replacement can cost around £300; similar in cost to a replacement gas valve.

However, before jumping to conclusions, there’s a quick-fix that your engineer can try. Your burner relies on a pilot jet to supply it with gas. These are incredibly small and therefore, can get blocked up easily.

Your boiler engineer can remove the jet, checking that it’s not blocked. They can either try manually removing the blockage, or if the blockage can’t be cleared, a replacement jet will fix the problem.

After the burner has been cleaned/replaced and the jet has been unblocked/replaced, resetting the boiler will clear fault code 4 from the control panel.

What does the PCB do on my Intergas boiler


The PCB is the most important part of your boiler. It gives and receives signals to electrical components such as the gas valve, burner, air pressure switch, fan and pump. Essentially, it’s a middle-man to ensure that all parts are operating when they should, and efficiently. When there’s a problem with your boiler, it’s the PCB that determines what that problem is, and therefore, decides which fault code needs to be displayed.

How could the PCB contribute to fault code 4 being displayed on my boiler’s control panel


So, if there’s a fault with the PCB, it can cause major problems. Although the PCB is suggesting fault code 4 (no flame signal), it might be the PCB that’s at fault. If there’s a flame in the boiler and the flame sensor is not the issue, the problem could lie with the PCB.

It only takes one loose wire or a single damaged connection for the PCB to work sporadically. Alongside showing fault codes like the one you see currently, you might notice:

  • Appliance cycling on and off at random
  • The LED display flickering
  • Controls on the front panel not responding to your commands

On some occasions, loose wires and damaged connections can be repaired. In extreme circumstances, the boiler’s PCB will need to be replaced in order to fix the problem.

How much will a new PCB cost in my Intergas boiler


After fault-finding and ensuring the PCB is the culprit, your boiler repair company might suggest a new PCB to fix the problem.

Unfortunately, the PCB is the most expensive part in your boiler. Typically, you should expect replacement costs to sit in the £400-500 range, depending on the exact boiler model you own.

And with costs this high, it makes sense to have the overall condition of your boiler checked. If multiple expensive parts are likely to fail soon, it might be worth considering a replacement boiler, rather than a costly short-term repair.

Other Intergas boiler issues


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