Steve Sutton, Technical Manager at the HHIC, explains why hydraulic or system balancing should be at the forefront of industry efficiency efforts.

With Boiler Plus now over a year old, it’s time to revisit some of the thoughts that came out of the initial consultation. 

The responses of more than 750 installers during the consultation period highlighted how only 18% claimed to undertake system balancing as standard practice, while some installers stated that they do not have a common understanding of system balancing. 

As a result, the Heating and Hotwater Industry Council (HHIC) is working to support installers and consumers in understanding system balancing – the process and the benefits. This isn’t about adding burden, but raising industry standards and ensuring systems operate as efficiently as possible. 

Checking and balancing a system should be part of the commissioning process, especially for low temperature systems. Some key points to note include:

  • There is no one reason for an unbalanced system
  • The amount of balancing required is dependent on the housing layout and system design
  • A common cause of unbalancing is the removal of radiators for redecorating purposes. These are then refitted without rebalancing, which affects the whole system
  • Consumers may try to overcome the effects of an unbalanced heating system by turning up the boiler thermostat or increasing the speed of the system pump – this increases energy consumption and doesn’t solve the root cause of problem. 

What is balancing?

Put simply, balancing the system is the process of optimising the distribution of water through the property’s radiators by adjusting the lock-shield valve, equalising the pressure of the system. Undertaking this process will ensure that the house is at the intended temperature, at minimal operating cost and optimal energy efficiency. 

This may seem trivial, but it could have a detrimental impact on the comfort of the homeowner and efficiency of the system. This is because, if the water flow through the system is not balanced, individual radiators could end up taking the bulk of the hot water flow – leaving others with a reduced flow rate. 

Systems with thermostatic radiator valves could become a noisy nuisance for homeowners if the system isn’t balanced, with water ‘streaming’ noises coming through the valves.  

When it comes to balancing, the first step is simply to remove the air from the system by bleeding the radiators in the home. Once this has been done, the heating should be switched off to allow the radiators to cool down. The next step is manual and requires the heating engineer to turn on the central heating and make a note of the order in which the radiators warm up – the nearer to the pump, the faster the radiators tend to warm up.

The heating engineer should then turn the flow valves (or thermostatic valves where fitted) to the fully open position and the lock-shield valves on every radiator in the home by turning them anti-clockwise. 

This next step is straightforward: the installer can simply touch each radiator in turn to see if they heat up at the same time – if they do, the system does not need adjusting. 

If the engineer finds that they are not warming up evenly, then the radiator that heats up first should have its flow restricted. You can do this by closing the lock-shield valve. The valve closure should start at 50%, with the installer monitoring the system and closing the valve further if needed – it may be necessary to close the valve by more than 80%. This will increase the flow rate to other radiators across the system. 

If some radiators remain cool, then the heating engineer should make further adjustments by restricting the hotter radiators in the system. Previously restricted radiators should be restricted even further, while those that weren’t restricted should be restricted because they are now hot. The installer should continue to monitor the system, but it is worth noting that changes to even one radiator could affect other radiators on the heating system. 

Technology has developed to the point where thermostatic radiator valves can be balanced using internal settings on the valve body. The installer will select the correct setting from a look up table for any given room and radiator size combination. 

Alternatively, new solutions such as circulator pumps can use an app to communicate with a smartphone or tablet, calculating the flow required for a specific radiator, then guiding the heating engineer to set the lock-shield valves correctly for each individual radiator and pipe run, ensuring accurate balancing and saving time. 

System balancing is a simple process, one that can provide optimal comfort to the homeowner and increase the efficiency of the heating system. It is an expected practice – one the heating industry should be shouting about further. Green gas and innovative technologies aside, balancing the system should be the first step to boosting household efficiency.