Price VPD-HC

Thermally powered VAV diffuser with independent cooling and heating setpoint adjustment, suitable for a wide range of commercial, retail and educational applications.

The Varitherm® self-modulating diffuser series is designed to provide accurate personal VAV control, while being easy to install, maintain and operate. Thermal sensors, mounted just above the plaque, sense the room temperature and modulate a damper according to the supply air temperature and load in the room – all done mechanically so there is no requirement for power or wiring.

Traditional VAV strategies include grouping rooms and spaces with similar loads and environmental requirements into zones, all controlled by a single VAV device and a single thermostat. As people have varying comfort criteria, there are often many who are left unsatisfied or uncomfortable by being placed in a zone where the thermostat is controlled by other people. Complaints of people being “too cold” or “too warm” are common as the system typically works to satisfy the occupant representing the “worst case” within the zone.

The Varitherm® eliminates this issue by allowing individual control at the diffuser level, providing much more flexibility and greater comfort. Patented technology allows the Varitherm® to provide highly accurate flow rates determined by the heating or cooling requirement in the room. The thermal actuators are constantly engaged with the damper and thus, provide constant feedback and enable precise control of the room temperature.

As the room load varies, the Varitherm® diffuser compensates by controlling the flow of supply air into the space. The diffuser is available in two models, a cooling only model and a heating-cooling model. Modulation for both models is precise and proportional to the requirements of the space and occupant. By varying the open area at the diffuser, a near constant velocity of supply air is maintained, even at very low flows.

This ensures that the Coanda effect is maintained at all flows and diffuser performance issues due to VAV turn down (dumping, for example) are eliminated. The actuator mechanism features robust thermal sensors that operate an engineered linkage to adjust the damper. An inletmounted thermal sensor provides the heating-cooling model with automatic changeover between heating and cooling modes.


Mixed airflow
4-way blow horizontal discharge from diffuser, which must be located in a closed ceiling for Coanda effect attachment to the ceiling surface.

Ceiling location
Ceiling mounted with supply air from above.

Fixed airflow direction
Non adjustable discharge pattern. Baffles available for 3 or 2 way air pattern.

Thermal adjustment
Thermal actuators with individually adjustable heating and cooling set-points (Varitherm-HC only).

Constant throw
Substantially constant velocity discharge for stable air flow pattern throughout the air volume range.

Square face shape
suitable for 600mm x 600mm ceiling grid.

Square face pattern
Steel plaque style diffuser face.

Metal Face
Steel diffuser face white powder coat finish B12

Airflow Direction


Face Material

Face Pattern

Face Shape


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