553 Series Auto Filling Unit – 3X Smarter Pressure Control

The automatic filling unit is a device consisting of a pressure reducing valve with compensating seat, an inlet strainer, a shut-off valve, and a check valve.

It is installed in the water supply pipework in sealed heating systems and its main function is to maintain the system pressure stable at a set value, automatically topping up with water, as required.

After installation, during the filling or topping-up phase, feed will stop when the set pressure is reached.

Set It and Forget It: 553 Series Automatic Filling Unit

Experience effortless performance and consistent system pressure with the 553 Series Automatic Filling Unit. Specially engineered for closed-loop heating systems, this device automatically restores water levels when pressure drops—no manual intervention required.

Whether you’re maintaining residential or commercial systems, this unit guarantees safety, efficiency, and peace of mind, protecting your boiler and components from low-pressure damage.

Integrated Design for Quick Installation and Reliable Operation

The 553 Series features a compact, all-in-one construction combining a pressure reducer, shut-off valve, and check valve. Built from high-durability, corrosion-resistant materials, it withstands high operating demands with ease.

With its pre-adjustable pressure setting, installers can set the desired pressure before installation—saving time and reducing setup errors.

Protect Your System, Save on Maintenance

Low water pressure can cause air to enter the system, reduce heat transfer efficiency, and damage pumps or boilers. The 553 Automatic Filling Unit prevents all that by maintaining optimal pressure, minimizing breakdowns, and extending the system’s lifespan.

This is more than just a valve—it’s a smart investment in the reliability and performance of your heating system.