10 Common Boiler Problems and How to Fix Them

Boiler problems are a headache for homeowners, especially as the winter months begin to set in. Leaky boilers and no hot water are often the results of a lack of boiler maintenance. That’s why every home must schedule an annual boiler service to prevent breakdowns before they happen.

This article explores the most common boiler problems you may experience at home and how to fix them.

Jump to a topic:

• The pilot light keeps going out
  • Faulty Thermocouple
  • A strong draught
  • Dirty Pilot Orifice
• No heating or no hot water
• The boiler is making strange noises
• Hot water but no heating
• Cold radiators
• Bonus – How to prevent boiler problems

The pilot light keeps going out

The pilot light in your boiling is the key to your central heating. The pilot (small flame) burns continuously to ignite the gas when the valve is opened.

When the pilot light opens, your boiler begins to heat the water, ready to be passed around your home. However, if this pilot light goes out, your boiler won’t work.

There are a few reasons your pilot light keeps going out. 

You could have a broken or faulty Thermocouple

The thermocouple is responsible for keeping your pilot lit. It sends an electric current to a sensor on the gas valve, which signals that the valve should stay open. 

If your pilot light goes out when you release the gas control knob after 20 seconds, that could be a sign of a thermocouple fault.

It’s important to note that gas appliances can be dangerous, so you should avoid trying to make repairs yourself. Instead, if you suspect your thermocouple is malfunctioning, you should call a Gas Safe registered engineer.

A strong draught indoors

You’d be surprised how easy it is to overlook, but a strong draught is a common cause for a pilot light to go out. So if you find your pilot suddenly goes out, particularly during windy days, there is a good chance it could be because of a strong breeze.

Despite a draught being a less complex issue, you should still contact a local boiler specialist. A strong draught shouldn’t be able to interfere with your pilot light. Therefore you may have some structural issues with your boiler casing.

Dirty Pilot Orifice

A pilot orifice is responsible for controlling gas flow to the pilot light. It only takes a small amount of debris to restrict the gas from flowing properly, which can lead to a small pilot flame or no flame at all.

So if your pilot light is a small, weak orange flame, there is a good chance you have debris in the pilot orifice. A boiler engineer must remove the pilot orifice and clean the debris using compressed air.

No heating or no hot water

Losing heat and hot water is one of the most frustrating problems people face with boilers. The challenge with identifying the cause is that there are several reasons your boiler isn’t heating your home or water.

Some of the reasons you may have no heating or hot water:

• Low boiler pressure can be caused by a water leak in your central heating system. Leaks are often the result of corrosion, a faulty seal or poor installation. You should establish if your leak is from your boiler or central heating system.
• Cold patches on your radiator could be a sign of a build-up of debris or air in your system. If the cold areas are at the top of your radiator and not the bottom, you may need to bleed your radiators.
• A faulty thermostat can cause cold water and, in some cases, boiling hot water from your taps. If your thermostat is defective, you will need to have it replaced
• Frozen condensate pipes are common during freezing temperatures. Check your boilers’ digital display first to know if this is the cause. If the display shows the error code ‘EA’, you likely have frozen condensate pipes. 

The boiler is making strange noises

It’s not uncommon for boilers to make some noise while they operate. However, if you notice unusual noises from your boiler, it may be time to investigate!

Banging noises could be the sound of kettling, where the water within your boiler begins to boil. This is often a result of limescale restricting water flow in your central heating system. On the other hand, tapping noises could also signal kettling. An engineer must clear the debris from the central heating system by performing a power flush. 

You can learn more about unusual boiler noises in this article.

Hot water but no heating

If you have hot water but no heating, the first place to check is your thermostat. First, shut down your central heating system and turn the temperature control to zero. 

Next, turn your central heating back on and turn the temperature up on the thermostat to check if the boiler fires. If the boiler fires, allow 15-20 minutes and then check your radiators are warming up. 

If your radiators aren’t warming up, you may need a boiler engineer’s help. It’s possible that you either trapped air in your central heating system.

Cold radiators

If your radiators are cold while the central heating system is on, then you may have a stuck valve within your radiator.

The thermostatic radiator valve (TRV) controls the flow of hot water to the radiator. It is not uncommon for the TRV to seize, preventing hot water from flowing in while the heating is on.

You can check to see if the valve is stuck by removing the head of the TRV. Underneath, you should see a raised pin. 

Press the pin with your finger. When you release the pin, it should rise back up again. 

If the pin is already pressed in or doesn’t move easily, you may have a faulty TRV.

How to prevent boiler problems

Unfortunately, there aren’t any guaranteed ways to ensure your boiler will never break down. However, you can reduce the likelihood of it happening.

The number one way to prevent boiler problems and increase the lifespan of your central heating system is through an annual boiler service. During the service, a boiler engineer will conduct a series of checks to see how well your boiler performs to help ensure your central heating system is operating efficiently.

The key advantages to a boiler service are that you can help ensure your boiler is working effectively and not overworking – which would cost you more on your energy bills each month. In addition, your engineer can spot faults early before they become a bigger problem. In many cases, your engineer can repair the defect there and then unless they need to order replacement parts.

An annual boiler service can help prevent unexpected breakdowns and cold winters for you and your family.

About the author

Trades Team are experts in Heating, Plumbing and Gas Services. We have 15 years of experience providing expert Boiler Repair and Boiler Servicing to homes and businesses across the Southeast. Learn more about Trades Team.