Vaillant WH280 Low Loss Header | 306725 | DN80 PN6

Description

The Vaillant WH280 Low Loss Header is a commercial hydraulic separator designed to maintain stable water flow through the boiler while supplying a consistent temperature to multiple downstream heating circuits. With a DN80/PN6 connection, a maximum flow rate of 21.5 m³/hr and a substantial 1390 mm height, it is suited to larger commercial heating installations where hydraulic separation and reliable circuit control are essential.

By creating a neutral point between the boiler and heating circuits, the WH280 helps prevent interaction between the boiler circulation pump and individual circuit pumps. This supports steadier operation, helps protect the heat generator and makes it easier to serve circuits with differing flow and temperature requirements, such as radiators and underfloor heating.

Connection

DN80/PN6

Max Flow Rate

21.5 m³/hr

Flow Capacity

21,500 L/hr

Pressure Drop

3.80 mbar

Height

1390 mm

MPN

306725

Installation notice: Vaillant low loss headers are intended for new, clean heating systems using correctly inhibited water. Installation must be carried out by a competent heating engineer in accordance with the manufacturer’s instructions and applicable UK regulations.

System compatibility: Confirm the required header size against the boiler output, system temperature spread and total heating circuit flow rate before ordering. The WH280 is a large capacity commercial header and may not be suitable for smaller domestic systems.

Installer benefit: The low loss header helps decouple the boiler from the heating distribution system, supporting stable boiler flow and reducing the risk of hydraulic interaction between multiple pumps.

Key Features

Hydraulic Separation

Creates a neutral point that separates the boiler circuit from downstream heating circuits, helping pumps operate independently.

High Flow Capacity

Handles up to 21.5 m³/hr or 21,500 litres per hour, making it suitable for demanding commercial heating applications.

Consistent Supply Temperature

Helps deliver a constant temperature supply to multiple circuits downstream of the header connection.

DN80/PN6 Connections

Features robust DN80/PN6 connections for integration into commercial pipework and boiler systems.

Multi Circuit Support

Well suited to installations with circuits that have different flow rate or temperature requirements, including underfloor heating and radiator systems.

Vaillant Commercial Accessory

Manufactured by Vaillant under model reference WH280, with manufacturer part number 306725.

Technical Specifications

General

Brand

Vaillant

Product type

Low loss header

Model

WH280

Manufacturer part number (MPN)

306725

Hydraulic Performance

Connection size

DN80/PN6

Maximum flow rate

21.5 m³/hr

Maximum flow rate

21,500 L/hr

Pressure drop

3.80 mbar

Dimensions

Height

1390 mm

Width

160 mm

Depth

160 mm

Application & Warranty

Suitable application

Commercial heating systems requiring hydraulic separation

System requirement

New, clean systems with correctly inhibited water

Warranty

1 year, subject to the manufacturer’s terms and conditions

Frequently Asked Questions

What does a low loss header do?

A low loss header provides hydraulic separation between the boiler and the heating circuits. It helps maintain the correct flow through the boiler while allowing downstream circuits to receive a consistent water supply.

Is the Vaillant WH280 suitable for domestic boilers?

The WH280 is a large capacity commercial low loss header with a DN80/PN6 connection and 21.5 m³/hr maximum flow rate. It should only be selected where the system design and boiler output require this capacity.

Can it be used with underfloor heating and radiators?

Yes. A low loss header can support multiple downstream circuits with different flow and temperature requirements, including underfloor heating and radiator circuits, provided the system has been correctly designed.

Does the WH280 require electrical components?

The low loss header itself is a hydraulic component. System controls, pumps and any sensors must be selected and installed according to the boiler manufacturer’s instructions and the overall system design.

What water condition is required?

Vaillant low loss headers are intended for new, clean systems with correctly inhibited water. The system should be flushed and treated in line with best practice and the manufacturer’s installation requirements.

Who should install this product?

Installation should be completed by a competent heating engineer familiar with commercial heating systems, hydraulic separation and the relevant UK standards. Correct sizing, pipework design and commissioning are essential for reliable operation.

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