Sealed System Filling Kit 1/2" | WRAS Loop For 4Ltr to 25Ltr

Description

The 1/2″ Sealed System Filling Kit gives installers a compact, ready-to-fit solution for filling and pressurising sealed central heating systems. It combines a double check valve, isolating ball valves and a flexible braided hose in one kit, so the mains cold feed can be connected and disconnected safely without introducing separate components on site.

Built in corrosion-resistant brass with a WRAS-approved backflow design, the kit is suited to domestic boilers, heat pumps and underfloor heating systems alike, and covers expansion vessel sizes from 4 to 25 litres. Its compact 1/2″ connections and flexible hose make it straightforward to fit in tight boiler cupboards or plant spaces.

1/2″ BSP

Connection Size

10 bar

Max Pressure

500mm

Hose Length

Brass

Body Material

WRAS

Approved

4-25L

Vessel Range Covered

Please Note

This kit is a filling loop and valve set only — it does not include an expansion vessel, safety relief valve or pressure gauge. Check what your system already has in place before assuming this kit alone completes a sealed system installation.

Important Safety Information

After filling and pressurising the system, the filling loop should be disconnected from the mains supply in line with water regulations preventing backflow contamination. Installation should be carried out by a suitably qualified heating engineer.

Good to Know

The integral double check valve protects the mains water supply from contamination, meeting the backflow prevention requirements expected of a compliant sealed-system fill point.

Double Check Valve

Prevents backflow into the mains water supply, protecting drinking water safety during and after the filling process.

Isolating Ball Valves

Lets the installer control water flow precisely and disconnect the loop cleanly once the system has been filled and pressurised.

Flexible Braided Hose

A 500mm braided flexible connector simplifies routing between the mains cold feed and the heating system in tight spaces.

Brass Construction

Corrosion-resistant brass fittings throughout give a durable, long-lasting connection point that withstands repeated use.

WRAS-Approved Design

Manufactured to meet UK water regulations for backflow prevention, giving confidence the kit is compliant for potable water contact.

Wide System Compatibility

Suitable for use with expansion vessels from 4 to 25 litres, covering most domestic boiler, heat pump and underfloor heating installations.

Kit Specification

Connections

1/2″ BSP

Valve type

Double check valve with isolating ball valves

Hose length

500mm, braided flexible

Max. pressure

10 bar

Material

Brass body, stainless steel braided hose

Approval

WRAS approved

Compatible vessel range

4 to 25 litre expansion vessels

Does this kit include an expansion vessel?

No. This kit is the filling loop and double check valve assembly only. An expansion vessel, safety relief valve and pressure gauge must be sourced separately if your system does not already have them.

Do I need to disconnect the filling loop after use?

Yes. Once the system has been filled and pressurised, the loop should be disconnected from the mains cold feed to prevent any risk of backflow contamination, in line with water byelaw requirements.

What size systems is this kit suitable for?

It is designed to work with expansion vessels from 4 to 25 litres, covering most domestic sealed heating systems, heat pumps and underfloor heating installations.

Can this be used on a heat pump system?

Yes, the kit is suitable for boilers, heat pumps and underfloor heating systems using a sealed, pressurised circuit.

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Room Dimensions

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Height (in m):

Room Type

Living Room

Bedroom

Kitchen

Bathroom

Conservatory

Hallway

Glazing Type

Single Glazed

Double Glazed

Triple Glazed

External Walls

0 Wall

1 Wall

2 Walls

3 Walls

4 Walls

Insulation Level

Poor

Average

Good (New Build)

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