Everything to know about Sealed Heating Systems

Your complete buyers and owners guide to sealed heating systems

The popularity of sealed heating systems is increasing in the plumbing market. Both businesses and homeowners are resorting to installing commercial sealed systems and domestic sealed systems for new and existing builds, driven by advancements in plumbing technology and the opportunity for heating system improvements.

At Altecnic, we have over 35 years of experience providing high quality plumbing and heating components to the plumbing trade and public. In this guide, we shall explore the key facts and points you need to know about sealed heating systems, so if you are searching “what is a sealed heating system?” or wondering if one is right for you, you are in the right place.

For more information, our plumbing experts are on hand to answer any questions or enquiries you may have. Contact us today for advice and support.

What is a sealed heating system?

Sealed heating systems (also known as closed-loop heating systems or pressurised heating systems) are an alternative to traditional, open vented heating systems. They are typically more compact and space efficient than their open vented counterparts, and use a pressurised expansion vessel system in place of an open vent or expansion tank.

Closed loop heating systems are completely closed off from the atmosphere. As a result, they are less prone to problems such as air locks and pipe corrosion that can make heating systems costly to maintain for both home and commercial property owners.

How do sealed heating systems work?

How is a sealed heating system different from an open vented heating system?

Sealed heating systems work by using a pressurised expansion vessel to accommodate for any fluctuations in system water pressure. Where traditional open vented systems release excess water through an open vent pipe into an expansion tank, expansion vessels work to maintain stable pressure levels without extraction of system water.

Expansion vessels are divided into two separate chambers: a water chamber (connected to the water system), and an air/nitrogen chamber. The vessel chambers are divided by a flexible diaphragm.

As water rises in temperature, it increases in volume, resulting in increased pressure in central heating system pipes. Excessive pressure can result in damage to boilers and pipes in your heating system, whilst increasing noise, risks of burst pipes, and reducing heating efficiency.

Sealed heating systems accommodate for this increased pressure by compressing the flexible diaphragm as water pressure increases. This compresses the air or nitrogen filled, pre-charged chamber, which causes excessive pressure buildup in the system. As the system cools, water contracts, and the compressed air/nitrogen in the expansion vessel pushes the water back into the heating system, maintaining a stable pressure.

What parts are required for sealed heating systems?

Expansion Vessels: Accommodates water expansion due to heating.
Filling Loop: Used to add water to the system
Pressure Relief Valve: Releases excess pressure to prevent system damage.
Pipes and Fittings: Connect the components together.
Pressure Gauge: Monitors the system pressure.

At Altecnic we offer a full range of ready-to-install, complete sealed heating system kits, including:

Robokit Compact Sealed System Kit: Sealed system kit comprising: expansion vessel up to 18 litre capacity, filling loop, safety relief valve, pressure gauge, integral mounting bracket and assembly connector allowing left or right installation on the system.
Robokit Compact Plus - Sealed System Kit: Sealed system kit comprising: expansion vessel up to 12 litre capacity, WRAS Approved filling loop, safety relief valve, pressure gauge, integral mounting bracket and assembly connector allowing left or right installation on the system.
Robokit Essentials Sealed System Kit: Sealed system filling kit comprising: filling loop, safety relief valve complete with gauge, mounting bracket to suit up to 25 litre capacity and manifold fitting.
Matrix Mini and Matrix Midi (Commercial): Suitable for maintaining pressure in large domestic and commercial sealed heating systems, chilled water systems, refrigeration units and industrial cooling systems.

For existing owners of closed loop heating systems, we offer a range of replacement system parts including: full flow differential bypass valves, expansion vessel brackets, filling loops and expansion vessels. Explore our range of components for domestic sealed heating systems and commercial sealed heating systems.

Can’t find what you’re looking for? We offer a complete range of plumbing parts and components for new installations, maintenance and repair. Speak to our experts today to discuss your requirements.

Which heating system should I choose: Sealed System or Open Vented?

Whether you’re carrying out a new build, or replacing a current central heating system, the decision between sealed heating systems and open vented systems can be tricky to navigate.

We have put together a list of the main benefits to help in your decision:

Benefits of Sealed Heating Systems:

Increased Efficiency: Reduced heat loss due to the closed system. Constant pressure leads to more efficient heat transfer.
Quieter Operation: No air escaping through an open vent pipe. Smoother water flow due to consistent pressure.
Reduced Maintenance: Fewer components to check and service. Less prone to air locks and corrosion.
Improved Comfort: Consistent heat distribution throughout the home. Faster heat-up times for central heating systems.
Enhanced Longevity: Reduced stress on system components due to consistent pressure.

Benefits of Open Vented Heating System:

Lower Initial Cost: Generally less expensive to install compared to sealed systems.
Simpler Design: Fewer components and a more straightforward system to understand.
Gravity-Fed Operation: No need for a circulation pump in some cases, reducing energy consumption.
Suitable for Older Properties: Can be adapted to existing plumbing in older homes.
Easier Troubleshooting: Simpler systems can be easier to diagnose and repair.

Regardless of your decision, we have the components and parts to assist you in your installation. With over 35 years of industry excellence, we are renowned for manufacturing high-quality, reliable, and long-lasting plumbing components inhouse in the UK.

Your trusted supplier of heating systems parts and components

No matter your choice, we have the components you need to install, maintain and repair your heating systems. From expansion vessels, safety relief valves and radiator valves, to components for heat pump systems, ball valves, and general plumbing accessories, we offer a complete range of plumbing parts for your systems.

Explore our range of products for domestic sealed heating systems and commercial sealed heating systems, or speak to our expert team for further advice and order enquiries.