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In winter, a malfunctioning boiler can turn your home from cozy to cold. Our guide to troubleshooting boiler systems equips you to handle any issue, from cold radiators to pilot light problems. 

Boiler systems provide heating and hot water in homes. Understanding different types of boilers is crucial for effective troubleshooting boiler systems. 

3 Types of Boilers 

• Combi or Combination Boilers 

• System Boilers 

• Regular Boilers 

What is a Combi or Combination Boiler? 

A combi boiler combines heating and hot water functions in a single unit. It doesn’t need a separate hot water tank or cylinder. Combi boilers heat water directly from the mains, offering instant hot water on demand. 

Combi Boiler on the Wall

What is a System Boiler? 

A system boiler uses a separate hot water cylinder. It includes built-in components like pumps and valves, making installation and maintenance easier. 

system boiler

What is a Regular Boiler? 

A regular boiler, also known as a heat-only or conventional boiler, uses a separate hot water cylinder and cold water storage tank. It’s suitable for properties with older heating systems or lower water pressure. 

Regular Boiler

Visual Difference Between Combi, System and Regular Boiler?

Components of Boiler System  

Understanding boiler components is key for troubleshooting:  

• Boiler Unit: Heats water and distributes it through the system.  

• Heat Exchanger: Transfers heat from the burner to the water.  

• Burner: Combusts fuel to generate heat.  

• Control Panel: Allows adjustments and monitoring.  

• Pumps: Circulate water through the system.  

• Pressure Relief Valve: Releases excess pressure to prevent damage.  

• Expansion Vessel: Maintains pressure levels during heating cycles.  

• Flue: Channels exhaust gases out of the property.  

• Radiator Heater: Distributes heat into rooms.  

• Hot Water Outlet: Delivers hot water to taps and fixtures.  

Knowing these components helps identify and fix issues and efficiently troubleshoot the boiler system.  

Boiler Working Principle  

All boiler types heat water for warmth and hot water. Cold water enters the boiler and is heated by gas, oil, or electricity. The heated water is then distributed throughout the home. System and regular boilers store heated water in cylinders. All types have controls and safety mechanisms to regulate temperature and ensure safe operation. Understanding this principle aids in troubleshooting boiler systems.  

Common Boiler Problems & How to Perform Troubleshooting Boiler Systems?  

Why Does Combi Boiler Lose Pressure?  

Common cause: a leak in the system.  

Troubleshooting: Inspect pipework, radiators, and the boiler for leaks. Repair any found or contact a heating engineer.  

Pressure Gauge Going Berserk After Turning Off Boiler?  

The likely cause is a faulty or blocked pressure relief valve.  

Troubleshooting: Inspect and replace the pressure relief valve if necessary.  

Boiler Automatically Turns On Every 5-10 Minutes Despite Zones Being Off?  

Possible cause: a faulty thermostat or programmer.  

Troubleshooting: Check thermostat settings and programmer for errors. Reset or replace if faulty.  

Why Boiler Suddenly Stops and Lights Become Red?  

Possible cause: boiler lockout due to low water pressure, lack of fuel, or ignition issues.  

Troubleshooting: 

• Check the pressure gauge and fuel supply. 
• Reset the boiler. 

If the problem persists, consult the manual for error codes and contact a heating engineer.  

Radiators Not Heating Up and Power Flush Didn’t Work?  

Possible cause: a faulty or stuck diverter valve.  

Troubleshooting: Inspect the diverter valve for malfunction or blockage. Repair or replace if necessary.  

Why Is My Boiler Making a Noise Like an Airplane?  

Possible cause: faulty pumps.  

Troubleshooting: 

• Check the pressure and bleed radiators to release the trapped air. 
• Inspect pump and heat exchanger. 

If issues persist, consult a heating engineer.  

These are common boiler problems and solutions for effective troubleshooting.