Viessmann’s innovative combined flue system connects 44 refurbished flats, meeting architect’s exacting requirements

Project Overview

The complete refurbishment of a disused office block in Stratford town centre has resulted in the creation of 44 new flats, each heated by a reliable Viessmann Vitodens 100-W boiler. With strict aesthetic guidelines in place, the installation called for a special combined flue system.

When East Thames Housing Association decided to redevelop a vacant office block in Stratford, they wanted an aesthetically pleasing yet energy efficient solution. Developed with £880,000 funding from the Mayor of London, Stratford Broadway was designed to provide a hub of activity for the area. In addition to 44 one, two and three bedroom flats, the site was earmarked to contribute to job creation, with two retail units included as part of the scheme.

As part of the transformation from office block to living space, the site required new heating systems for the flats, which importantly would not affect the visual quality of the building. Allford Hall Monaghan Morris (AHMM) architects insisted that the fascia of the building had to be completely clear of flues and drains. A new atrium glass roof closed off corridors between the flats preventing the more discreet positioning of flues there too. An new solution was needed.

A space saving, ‘off the shelf’ combined flue system by Viessmann

As space to flue the boilers was limited and with standard flue lengths failing to meet the requirements, a combined flue system (CFS) was chosen as the best solution for the development. The Vitodens’ flue length can reach up to 19 metres for horizontal and vertical applications. For the Stratford Broadway project, the CFS, at around 15 m in height, connects all the properties, beginning on the ground floor and terminating on the roof. The concentric system was deemed a much safer option than using a twin flue alternative, as it avoided piping being routed through any dwelling. The Viessmann flue, which uses less space than its counterparts, could be cut to size onsite.

Forty Vitodens 100-W 26 kW gas condensing combi boilers were fitted in the one and two bedroom flats. A further four 26 kW Vitodens 100-W system boilers were installed in the three bedroom flats that had higher hot water demand.

The Vitodens boilers’ compact proportions and the use of a combined pressure release valve (PRV) and condensate connection on each model meant that locating the boilers in the centre of the building proved easier, as the combined PRV and condensate connection can be routed in the CFS, which is drained away by a single outlet.

On time and matching the specification

By ensuring delivery was made within two weeks of the order, the solution offered by Viessmann met the targets set by the architects and the customer. Geoff Pearce, director of development and planning at East Thames Housing Association said, “We are proud to be part of Stratford’s continued regeneration and are passionate about improving the communities we work in. Providing new homes and retail space at Stratford Broadway is
testament to that.”

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