Regardless of the type of heating system you’re working on, removing air from the system is crucial to ensure its ongoing performance and health. Here, Pete Chamberlain from Spirotech looks at the different solutions available for air removal and which types of system they should be used for.
Air can be present in a heating system in a number of different ways, from free air to microbubbles and dissolved gasses. If left untreated, microbubbles will eventually be reabsorbed into the system water, where the oxygen will react with any ferrous internal surfaces and gradually corrode the system. This can lead to a number of potential issues, from simple annoyances such as noisy pipework and radiator cold spots, the need for frequent maintenance, or regularly needing to bleed the radiators, and in the worst-case scenario premature parts failure within the boiler.
For the best results, it is important that installers are specifying air removal to their customers for any wet heating system. However, with various solutions available, it is important to understand the difference between them, the benefits that each offer, and which type of system they best suit.
Ongoing protection
When it comes to domestic gas systems, installers should look to recommend some form of deaerator to offer ongoing protection against the presence of air. While an automatic air vent (AAV) is very useful for the ongoing release of free air, they are not suitable for removing microbubbles which, due to their small size, have a hard surface tension and cannot join to form a larger bubble that can be released by the AAV.
This is where a deaerator, such as the SpiroVent RV2, comes into play, to effectively and continuously remove microbubbles from a heating system. Utilising specialist tube technology, a Spirotech deaerator fitted on the flow pipe, at the point in the system with the highest temperature and lowest pressure, will create the right conditions for microbubbles to rise upwards out of the water, before being released by an automatic valve at the top of the unit. For the very best results, a deaerator should always be fitted alongside a dirt separator to offer maximum system protection.
With the right water treatment solutions, homeowners can expect to see efficiency improvements that will help to offset ever-increasing energy bills. For example, when installed together, the SpiroVent RV2 and SpiroTrap MB3 help to improve efficiency by up to 13%.
Mini vacuum degasser
On air-to-water heat pump systems, a small degassing unit will be a better solution than a deaerator, as this type of unit is better suited for low temperature and low pressure systems, where it is hard to predict where air will be released.
A mini vacuum degasser, such as the SpiroVent Superior S250, creates its own environment to release gases from the fluid, meaning it is not dependent on a specific location in the system; no matter where it is installed or the flow temperature of water within the system, it will remove air.
The unit works by drawing off a portion of the saturated fluid in the system, then creating an ‘under pressure’ in the vacuum vessel of the unit that causes dissolved gases to be released. These liberated gases accumulate at the top and can then be expelled.
Additionally, vacuum degassers can be particularly helpful in buildings where there are multiple storeys and installers are questioning whether to fit a deaerator like the SpiroVent RV2 at the hottest point of the system – on the return close to the boiler – or at the top of the system where gases naturally rise to.
Multi-zone systems
When working on larger domestic and light commercial systems, heating engineers are more likely to be dealing with multiple zones. In these instances, a hydraulic separator may be required to ensure the circuits do not interfere with each other and cause system inefficiencies.
A hydraulic separator such as the SpiroCross AX-J should be considered in systems where primary and secondary pumps are used, when primary and secondary flows are not equal, or when a constant primary flow is required. A well-designed hydraulic separator will not only perform hydraulic balancing, but will also have both deaeration and dirt separation capabilities too.
By making themselves familiar with these various technologies and in which situations they should be used, heating engineers will be in a prime position to deliver their customers a well-protected system that will stand the test of time.
