We do not give much thought to our boiler expect when we need it to pump the supply of hot water and provide heat. A broken boiler can cause chaos in the house. At that time, households wish they knew about common boiler problems and their solutions.

10 Most Common Boiler Problems

Keep yourself informed by learning about the common boiler problems. Here’s a list top 10 you will encounter time after time with a solution to fix.

#1: No Heating or Hot Water

There could be many possible causes. A broken diaphragm, valve or thermostat. A good place to start is checking the thermostat. If the problem isn’t the thermostat but a part is broken (valve, airlock or diaphragm), then simply replace them and your boiler will start working again.

#2: Water Leakage

A boiler can leak water because of a variety of issues. To determine the cause, it’s important to learn where the water is leaking from. Usually, it happens when an internal component of the boiler such as a pressure valve or a pump seal is broken. If the leak is because of the pressure valve that means the boiler pressure was high. On the other hand, if it’s coming from the pump seal that means it needs replacement.

Sometimes, the boiler is leaking from around the tank or pipes. This happens because of corrosion or improper fitting.

#3: Lower Boiler Pressure

A boiler starts losing pressure because of reasons such as water leak, broken valve or bleeding radiators. It’s very simple to check the boiler pressure. All you have to do is have a look at the built-in pressure gauge. If the needle is below 1, that means the boiler pressure is low. This is probably why the central heating system is not functioning properly.

Check the boiler for visible leaks. If you find any, call a registered engineer. If there is no leak, then reset the boiler pressure. Follow the manual of your boiler for instructions.

#4: The Boiler Is Cutting Out

Sometimes, the boiler powers up fine but trips in between or switches off. This also happens because of low pressure. When you experience this problem, check the pressure gauge. If the needle is below 1, simply re-pressure the boiler.

If the boiler pressure is fine, then chances are air is trapped which can be fixed by bleeding the radiators.

#5: Unusual Boiler Noise

It’s normal for the boiler to produce a low hum. However, if it is making a louder and unusual sound, then this could be a sign of a serious problem.

You will hear the boiler either whistle or gurgle. The boiler whistles when air is trapped in the pipes or the boiler itself. Bleeding the radiators solves this issue. If the boiler is gurgling, it means there is a frozen pipe somewhere that is disrupting the water flow. You might have to call a gas safe engineer to locate the frozen pipe and deal with the problem. That should fix the noise.

#6: No Pilot Light

The pilot light in a boiler is a small blue flame that keeps the burner lit. If it keeps going out, the boiler won’t work efficiently. This usually happens when the thermocouple is broken and it’s disrupting the gas supply.

When you are trying to reignite the light, make sure you check the gas supply for issues. If the gas stopcock is on but the boiler is not receiving the gas, it’s a sign you need to call an engineer. You can also reignite the pilot light yourself by following the instructions in the manual.

#7: Frozen Condensate Pipes

All boilers have a condensate pipe. This pipe transports acidic water produced as a result of waste gas out of the boiler. Usually, the pipe runs outside into the drain. Depending on its location, the pipe can freeze during winter.

If the pipe is frozen, your boiler will display a warning notification or a faulty code. The condensate pipe is a plastic pipe leading outside the house into the drain.

To fix the problem, place a hot water bottle, warm cloth or a heating pack on the frozen pipe. You can also pour hot water on the pipe. Once the pipe is fixed, reset the boiler so that it starts firing up again. You can fix this problem yourself. However, if you feel unsafe, you can call a heating engineer.

#8: Radiators Not Heating Up

When the radiators are not heating up, this could be because of built-up sludge or air in the system. Sometimes, only the bottom of the radiator is heating. In that case, the radiator needs bleeding. The process of bleeding the radiators is straightforward, you don’t need a heating engineer for help.

If some radiators are heating up and some are not, they might need balancing out. To balance the radiators, adjust the valves on all the radiators. This makes sure each of the radiators is getting enough hot water to work effectively.

When the problem is not related to the balance or bleeding, then chances are built-up sludge is preventing the flow of hot water to the radiators. Don’t try cleaning the sludge by yourself. Call a heating engineer. They use chemical flushing to clean the system and remove the sludge.

#9: Thermostat Issues

When the thermostat is turning the heating on and off or it is losing accuracy, this means you need to replace it. Sometimes, the thermostat is fine, you just overlooked some common sense checks such as:

• Make sure the thermostat is on
• Make sure it’s setting (time and schedule) are correct

Thermostat issues appear when the home is warmer and the thermostat is not allowing the boiler to heat the home on the temperature higher than what’s set. If that’s the case, increase a new increment until you are happy with the temperature settings.

If none of the above fixes applies, it means your thermostat is broken or losing accuracy. To fix this problem, buy a new one. 

#10: Hot Water Doesn’t Work, But Heating Does (Or Vice Versa)

Older boiler units often cause this problem. There is usually one fault – a diverter valve.

A diverter valve is responsible for filtering hot water to taps. It’s also responsible for the heating. It focuses the hot water towards taps first. When the taps are off, it uses hot water to heat the house.

The valve gets stuck over time because of sludge and debris. When this happens, it either affects the hot water supply or heating.

If there’s sludge is on the heating, you will get warm water but no heating. On the other hand, if the sludge is on the hot water side, you will get heating but no warm water. To fix this problem, call a heating engineer to perform a chemical flush.

Tips to Maintain the Boiler

Boiler problems can be messy. They will not appear all of a sudden if you maintain your boiler regularly. This maintenance advice might help:

Annual Boiler Service: Just like any other appliance, boilers function well and longer when serviced annually. Getting the boiler serviced actually ensures the warranty of the boiler valid. When the heating engineer comes to service the boiler, highlight issues you were encountering such as leaks or unusual noises. This will reduce damage before the problem escalates or your boiler breaks down completely.

Observe the Pressure: Over time, boilers start losing pressure. Make it a routine to check the boiler’s pressure. It should be between 1 and 1.5. If the needle is below 1, top up the water. Reach the manual to learn how to increase the boiler pressure.

Keep the Boiler Well-Ventilated: Your boiler might be placed in a confined space. If there are other objects placed around the boiler, this could be a problem. Some boilers need proper ventilation. Placing objects around them restricts the airflow. The unit will starve oxygen and lose its efficiency because of that. Restricted airflow can even damage the unit.

Make sure your boiler is placed in a well-ventilated room. Check the manufacturer’s manual regarding boiler ventilation.

Inspect the Radiators: Looking after the radiators can improve the efficiency of the boiler. The unit won’t have to work harder if the radiators are properly functioning. Air gets into the radiators over time. Common signs include a cold patch on a warm radiator or radiators not warming up at all. To resolve this issue, bleed the radiator. A part of maintaining the radiator is also checking built-up sludge at the bottom of the radiators. If you see any sludge, call an engineer to flush your system.

Safety Checks: To further ensure your boiler is in a good working condition inspect the following:

• Flue and combustion
• Proper functioning of electrical connections, electrodes, and fans
• Check the safety devices
• Condensate pipes and traps are free-flowing
• Seals are intact

Seal Your Home: To make sure the boiler runs efficiently, keep your house well insulated. Get rid of the holes and gaps that could make the heat escape the house. You can seal the doors and windows by adding draught excluders. Choose vulnerable areas like loft hatch or chimney flue. If the windows are in a poor condition, repair or replace them. To boost heat retention, install insulation around the house.

Find the Right Temperature: Heating and hot water needs keep on changing throughout the day. You won’t need hot water and a warm home all the time. Hence why experts recommend maintaining the temperature to 18 degrees Celsius while you are asleep or when you are not home. Other times, keep the temperature to 21 degrees Celsius at maximum.

Boiler Problems That Need an Engineer: You cannot fix all boiler problems on your own. Some intense problems demand a gas safe certified heating engineer. It’s time to call an engineer when you encounter the following boiler problems:

• The diaphragm or airlock is broken and there is no heat or hot water
• A part of the boiler is broken which is causing a water leak
• The radiators are not working because there is sludge or air built up in the system
• The boiler is making unusual noises

Things to Check Before Calling the Engineer

Before calling an engineer, it is best if you check your boiler just to be sure you don’t end up calling a professional for a problem you could have fixed easily. Check your boiler for the following:

• Check the gas supply. For that, check all other appliances that operate on gas. Are they working? If they are not, chances are something is wrong with the mains and for that, you will need an engineer.
• Check the power supply. Sometimes, the fuse just trips and a simple reset can fix the problem.
• Check the heating control. Take out the manual and see how to set the thermostat correctly. Sometimes, all it needs a resetting and the boiler starts working again.
• Check boiler pressure. Lower pressure causes a boiler to either function inefficiently or stops working completely. When the bar at the pressure gauge is below 1, the boiler needs filling. You can fill the system with water by yourself. If you are not sure how to do it, you can call an engineer.
• Press the reset button. Sometimes, by simply resetting the unit, minor problems go away. Make sure you try that. If the problem still persists, reach out to a heating engineer.

Summing Up

Most boiler issues arise during winter when you need heat and hot water the most. Since a boiler is one of the most important appliances in the house, all households must know about the common boiler issues. It’s also useful to know how to fix them to avoid costly repairs.

You can minimize boiler problems by maintaining the boiler, its components, and the heating system. Other times, some boiler problems are inevitable. You have no choice but to call a heating engineer.  When the need arises, call a gas safe certified heating engineer. They are experienced individuals with the right skill set to fix the problem.