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Common Intergas Boiler Problems


Intergas is a Dutch boiler company. It has more than 50 years of history and is actively involved in boiler technology. The company has a special heat technology patent which makes the boiler unique.

Having a high-tech boiler lockout on you or overheat when you are in a hurry is a huge inconvenience. You’ve probably experienced a couple of lockouts but didn’t know what the code on the boiler meant.

we reveal the most common Intergas boiler problems and their fault codes. Though some fixes are DIY, some need a professional hand.

Low boiler pressure

Low boiler pressure is denoted by a 0.0 fault code. The PCB recognizes when the boiler pressure falls and lockout the boiler. Normal boiler pressure is between 1 and 1.5 bar.

Low boiler pressure is caused by:

  • Airlocks – Air gets into the system through the addition of water
  • Leaks in the system – A small leak is enough to cause low boiler pressure. Leaks can be found in the pipework, radiator and towel rail.


If you add water to the system through the external filling loop and the boiler still loses water, it means you have a leak in the system. Contact a Gas Safe engineer to close the seal or repair the broken or cracked boiler component.

But if it’s an airlock, bleeding the system will solve the problem.

Overheating boiler

When a boiler overheats, you’ll see the’1’ fault code. Although this fault code helps in narrowing down the boiler problem, it’s not specific. Anything related to water circulation can cause the problem. The possible causes include:

  • Airlocks
  • Faulty pump

Airlocks like debris blockages create hotspots in the system. Also, a faulty pump isn’t efficient in pumping hot water through the system. This results in hot water remaining in the system for a long time.


The Gas Safe engineer will bleed air from the pump, radiators and towel rails. They will also top up the system to maintain optimum boiler pressure. After bleeding the boiler, they will reset it to clear the fault code.

The Gas Safe engineer will also check for faults in the pump including incorrect speed settings and blocks. The engineer will set the correct speed and unblock the pump through a Powerflush. However, if it’s faulty, it will be replaced.

No flame

The PCB controls the opening and closure of the gas valve. Consequently, it controls fuel served to the burner. However, the PCB cannot recognize the ability of the boiler to establish a flame. This is left to the boiler flame sensor which sends feedback to the PCB. Therefore, if the flame sensor is faulty, the PCB doesn’t receive feedback saying the flame is on.

This is a risky problem and can result in an explosion. To prevent this, the boiler will lockout and display fault code 04.


The Gas Safe engineer will inspect the flame sensor. If it’s faulty, there are high chances the boiler is establishing a flame. The flame sensor will be replaced.

If it’s a faulty or stuck gas valve, it will be repaired/replaced or freed respectively.  A new gas valve costs about £300.

Fault detecting flame

This fault is denoted by fault code 06. It is different from fault code 04 because the flame could be present only that it’s not being detected. The problem is with the flame sensor.


The Gas Safe engineer will check for:

  • A faulty gas valve
  • Low boiler pressure
  • Blocked burner
  • Faulty flame sensor
  • Blocked condensate pipe

With the exception of a blocked condensate pipe which you can thaw with hot water, the rest should be fixed by a Gas Safe engineer.

Fan Fault

When the fan doesn’t rotate at the required, the boiler displays fault code 8. The fan is a safety component. It creates a draught that pushes harmful gases up the flue and out of the property. If the fan isn’t working, the harmful gases build-up in the boiler. To prevent accidents, the boiler will lockout.


The Gas Safe engineer will adjust the speed to ensure harmful gases are expelled from the boiler. If this doesn’t work, it means the fan is faulty and will be replaced. Fan replacement costs about £300.

Faulty heat exchanger sensor

If your boiler is showing the 14, 13, 12, 11 or 10 fault codes they point to the same thing – a problem with the heat exchanger sensor. The heat exchanger the S1 and S2 sensors which monitor the flow and return water respectively.


The most direct fix is S1 sensor replacement. However, it’s not always as direct. Usually it’s a circulation problem. In this case, there might be limescale build-up. Powerflushing the system will get rid of the limescale and any blocks.

Also, the engineer will install a heating inhibitor, a magnetic and limescale filter to prevent future blockage.

But if you are dealing with a cracked heat exchanger, you’ll need to replace it or install a new boiler.

Frozen condensate pipe

The frozen condensate pipe is located outside the house. It drains waste boiler water into the drainage system. Because of its location, it’s prone to freezing and blockage during winter. When it blocks, the boiler shuts down to prevent further boiler damage.


To unblock the condensate pipe, thaw it by pouring warm water on the blocked section. Though this is a simple DIY process, you can hire a Gas Safe engineer if you don’t feel comfortable doing it yourself.

Radiators not heating

The radiators not heating up could be because of: air build up in the boiler system and sludge build-up. If only the bottom half of the radiator is getting hot, bleeding it will solve the problem.


Bleeding the radiator is simple and doesn’t need a Gas Safe engineer (but if you are not confident doing it alone, hire a Gas Safe engineer). Once bleeding is done, you can reset the boiler and the error will be gone.

Hearing strange noises

Strange boiler noises are common. However, they point to underlying boiler problems. Kettling noises are caused by trapped air in the system.


When there’s a lot of air in the system, the radiators will not heat up efficiently. To get rid of the air, you should bleed the radiators. Also, you should hire a Gas Safe engineer to Powerflush the system and get rid of the sludge and limescale built-up in the system.

Faulty gas valve

Unlike most error codes, fault code 29 is specific to gas valve problems. Usually, the relay is faulty. However, if the relay is intact, it’s a gas valve fault including loose or damaged connections and wiring.


The Gas Safe engineer will inspect the power to these components using a multi-meter. He will replace or tighten damaged or loose connections. If the gas valve is stuck, the engineer will free it.

Replacing the gas valve is the last resort to fixing the boiler problem.

Other fault codes and troubleshooting

Fault code 30 – faulty gas valve relay

How to fix: replacing the gas valve and resetting the boiler

Fault code F000 – Sensor defect

How to fix: Replacing the heat exchanger sensor

Fault code F003 – High flue gas temperature

How to fix: Tighten and repair damaged connections and wiring

Fault code F007 – Insufficient ionization flow

How to fix: Replace ignition pin wiring

How to improve your boilers life?

Intergas boiler warranty

Intergas boilers come with 1 year warranties. However, the warranties can be extended to between 3 and 10 years. To get the extended warranty you need to register your boiler online within 30 days of installation.

Luckily, most boiler installers help in the registration process immediately after installation. Also, the annual service is mandatory to maintain the warranty.

Intergas boiler service

Boiler servicing is carried out by a Gas Safe registered engineer. They carry out checks and tests to ensure the boiler is in perfect working order.

The check includes:

  • Running the boiler
  • Open and clean the boiler parts
  • Visual inspection

Make an enquiry today for a free quote. We shall provide you with affordable quotes from multiple capable boiler engineers.

Intergas boiler cover

When your warranty period ends, you can extend boiler protection using the Intergas boiler cover. Read the fine print before choosing any boiler insurance.

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