VTI launches a C4 hybrid extractor for individual ducts

VTI completes its range of hybrid extractors with the MAXIVENT MV2 EC PLUS C4. This low-pressure static-mechanical solution is intended for individual ducts ensuring the evacuation of stale air and combustion products in multi-family buildings undergoing renovation.

The device can operate in static mode, utilizing thermal draft and wind power, or in dynamic mode thanks to its motor. Mechanical assistance kicks in when natural forces are no longer sufficient to achieve the necessary flow rates and pressure levels.

A response to configurations combining boilers and ventilation

The new extractor primarily targets existing buildings in which individual ducts have a mix of boiler combustion product evacuation and apartment ventilation.

These configurations can limit the solutions available during an energy renovation, particularly when the project must retain all or part of the existing ductwork. The MAXIVENT MV2 EC PLUS C4 is designed to be installed at the duct outlet to maintain negative pressure and limit the risk of backflow.

According to the technical documentation published by VTI , the extractor ensures a minimum negative pressure of 3 Pa at the boiler nozzle during mechanical operation. In static mode, it is presented as a class B backflow preventer, in accordance with the requirements of Annex C of NF DTU 24.1 P1-2.

An architecture designed to protect the engine

To achieve the advertised thermal performance, VTI has revised the airflow and engine cooling systems. The architecture is based in particular on:

• an engine compartment isolated from the main flow;
• a circuit dedicated to the circulation of cooling air;
• aerodynamic optimization of the extractor;
• a design aimed at limiting heat transfer to the engine.

The manufacturer also states that it has simplified the mechanical architecture to reduce the number of components, manufacturing costs, and maintenance requirements. However, no comparative figures are provided for these three aspects.

"This innovation allows us to adapt to the most complex renovations, where the technical constraints of individual ducts require extraction solutions that are efficient, secure and energy-saving," explains Sylvain Mondina, Head of Design and R&D at VTI.

Operating temperature is advertised at 400°C for 30 minutes.

The PLUS version is presented with a C4 rating, corresponding to operation at 400°C for 30 minutes. VTI indicates that this performance has been verified by a fire resistance rating report issued by Efectis.

The report number, its validity date, its precise reference number, and the installation conditions covered are not, however, included in the public documents consulted. This information must be verified before any prescription is issued, as the performance of equipment classified as C4 is only valid within the scope and conditions defined by its report.

The extractor's classification alone is not sufficient to determine the conformity of the entire ventilation and combustion product evacuation system. This also depends on the ducts, accessories, connected appliances, control devices, and implementation conditions.

Two versions for individual ducts

The MAXIVENT MV2 EC PLUS C4 is offered with two types of cones:

• a version with a stainless steel cone, referenced EX315;
• a version with a concrete cone, referenced EX316.

The technical specifications mention a weight of 5 kg and an internal connection diameter of 125 mm. Adapters, sold separately, are available for rigid or flexible flue liners with diameters of 125 and 139 mm. On a masonry flue, the concrete cone can be sealed to the capping slab or to an adapter piece supplied by VTI.

Promoting natural draft to limit consumption

The hybrid system allows the engine to remain off when thermal and wind power are sufficient to ensure extraction. Mechanical assistance is activated when external conditions become inadequate.

This alternating system should reduce electricity consumption compared to continuous motorized operation. However, VTI does not provide, in the information provided, any reference annual consumption figures or measured comparisons with other solutions.

The manufacturer also highlights easier maintenance through mechanical simplification, a reduced risk of failure in case of high temperature and several finishes allowing the equipment to be adapted to the architectural constraints of buildings.

Integration with the Ventileco Gas Hygro system

VTI announces that it has integrated the MAXIVENT MV2 EC PLUS C4 into the technical specifications of its Ventileco Gaz Hygro system. This solution combines ventilation of dwellings and extraction of combustion products from natural draft gas appliances.

The page dedicated to Ventileco Gaz Hygro indicates that the system is specifically designed for multi-family buildings constructed before 1982, equipped with natural draft gas appliances and individual ventilation and flue ducts. Its specifications are the subject of a Socotec technical survey, reference number FAC 3068/1, which is scheduled to remain valid until December 20, 2027.

The compatibility of the new extractor with each operation will nevertheless have to be checked based on the updated version of the specifications, the Efectis report and the characteristics of the existing installation.

A patent application has been filed.

VTI indicates that it has filed a patent application relating to the extractor's architecture. This step potentially protects the claimed innovation, but does not mean that a patent has already been granted.

The manufacturer presents the MAXIVENT MV2 EC PLUS C4 as the only available solution for certain configurations combining individual ventilation and flue ducts. This marketing claim is not supported by any comparative studies to verify its validity.