Is the central heating pump part of the boiler?

It’s no secret that hot water needs to move throughout a building for the central heating system to perform its function. While this process involves many boiler parts working in unison, the central heating pump is the most important. 

Why is this? And if anything goes wrong with the central heating pump, where can it be found? That’s what we’ll be discussing in this blog. 

What does a central heating pump do? 

The central heating pump is responsible for transporting hot water to a building’s radiators, after it has been heated by the boiler. The pump will also circulate the water back to the boiler once it has cooled down. In a conventional boiler, this part ensures water is allocated to the central heating system as opposed to the taps and shower fittings. 

A central heating pump will pressurise the water to ensure it travels at speed to the radiators. This is important, as it prevents the water from losing temperature during the journey. Loss of temperature is synonymous with a loss of efficiency. As such, if you notice your central heating is not responsive or losing effectiveness, it could be due to a faulty pump. The central heating pump impeller pressurises water by transferring energy to the liquid through rotation. 

Equally, a pump pressure that is set too high can result in greater costs to the property owner or renter. This is because it causes more water than necessary to be transported throughout the building, thereby increasing both the water and electricity bills. 

Central heating pump components 

While the central heating pump is not a complex heating device, it does contain multiple components to perform its function. As a result, it’s usually only necessary to source select boiler replacement parts if a pump is found to be malfunctioning. These parts include: 

• Water flow inlet – the circular opening where returning radiator water enters the pump. The diameter of this component influences the overall flow rate of the pump. 
• Pressure adjust – an electronically powered dial that can be used to make manual adjustments to the pressure level of the pump. 
• Water flow outlet – the port where pressurised hot water leaves the pump to travel around the central heating system, including radiators and pipes. As with the inlet, the diameter of a pump outlet is a factor in determining maximum flow rate. 
• Impellers – a rotating mechanism that pressurises water inside the pump. 
• Bleed screw – a screw typically located on the front of the pump. Removing the bleed screw according to manufacturer directions allows trapped air to be bled from the system. 
• Electrical components – central heating pumps feature electrical connections to pass signals between various components. This is a more prominent feature in pumps that utilise automation. There will also be a supply cable that connects the pump to the mains. 

Some pumps feature a dial that allows for the water pressure to be manually adjusted. However, this is only recommended on the advice of a professional. Oftentimes, central heating pumps can be adjusted to ensure efficiency when heating buildings of different sizes. For instance, a boiler in a single bedroom flat does not need to be highly pressurised to provide heat to the structure. 

Types of central heating pump 

Central heating pumps come in many varieties and sizes to ensure the boiler can heat whatever property it is installed in. These types differ based on the speeds at which the pumps can be set, including:  

• Single speed – one speed without the option to be adjusted. Although quite rare nowadays, this pump is typically used to heat smaller homes and apartments. 
• Multiple speed – a pump with around three different speed settings that can be freely adjusted by an individual. 
• Variable speed – an automatically adjusting pump that can change its speed of flow while the central heating is in operation. This type of pump is not advised for properties with thermostatic radiator valves (TRVs). 
• Combination – offers flexibility between a variable setting or one of three fixed speed settings.

Where is the central heating pump located? 

As mentioned above, central heating pumps are chosen depending on the building and its heating requirements. The nature of the property also influences where the pump is located. It has to be close to the mains electricity supply, as well as the boiler. Bearing this in mind, common locations include: 

• Under the stairs. 
• In an airing cupboard. 
• In or near the bathroom. 

Combi boilers 

As combi boilers are designed from scratch to provide heat for the central heating as well as taps and shower heads, they feature in-built pumps. In this case, the pump can be found inside the boiler itself. 

Central heating boiler parts and spares 

If an issue with the central heating pump persists, you’ll need to seek out a heating spares professional. NBS has a vast range of boiler spare parts all manufactured and refurbished to BSI standards. Our quick turnaround times mean you’ll never be left without heat for long. Contact us today.