Variable air volume diffusers shall be AnemoTherm diffusers, Model ATC (cooling) & Model ATHC (heating/cooling) plaque type ceiling diffusers as manufactured by Anemostat. The diffuser size shall be nominal 24” x 24”, with a minimum 18” square appearance panel. The horizontal air discharge pattern shall be 360° type.

The diffusers shall be self-contained, and not require any external electrical or pneumatic connections. The damper shall consist of a spun, round aluminum disk that moves to change the effective free area of the diffuser to modulate flow. The damper shall include a perimeter seal. Each VAV diffuser shall incorporate one or more thermo-powered sensing elements that modulate the diffuser damper in response to the room temperature as sensed by the induced flow across the sensing element(s). The setpoints shall be factory pre-set at 74° F, but shall be field adjustable from 72°-78° F.

Model ATC cooling only VAV diffusers will be direct acting and shall utilize a single thermo-powered sensor to modulate the diffuser damper in response to the cooling setpoint.

Model ATHC heating & cooling VAV diffusers shall consist of multiple thermo-powered sensors that monitor the supply air temperature and index the diffuser into the heating or cooling mode. With the supply air temperature less than 68° F, the diffuser shall enter the direct acting cooling mode, and shall modulate the diffuser damper in response to the cooling setpoint. With the supply air temperature greater than 78° F, the diffuser shall enter the reverse acting heating mode, and shall modulate the diffuser damper in response to the heating setpoint. Diffuser shall be true VAV for both heating and cooling modes, and shall have independently adjustable setpoints for heating and cooling.

The diffusers shall be constructed of (steel)(aluminum)(304 stainless steel), and shall be designed to integrate with the specified ceiling system type. The diffuser shall consist of a back pan and a removable, heavy gauge appearance panel attached to the back pan. Room temperature setpoint adjustments shall be made by removing the panel, and rotating the appropriate thermo-powered sensor(s). No tools shall be required. 

The appearance panel shall have aerodynamic, rigid, hemmed edges around the perimeter and shall be a single piece construction. The panel shall be flat, smooth, and shall be free of any welding or forming blemishes. Holes or plug buttons in the panel are not acceptable.

Provide the following accessories as scheduled:
Blank-off baffles to obtain 1,2,or 3 way blow patterns as scheduled.
Relief collars to bypass supply air directly into the ceiling plenum (models ATCR, ATHCR)T-bar frames for hard surface ceiling installations.

Diffuser finish shall be (Arctic white)(satin polish finish-stainless only)(color as selected by the Architect).

Each diffuser shall be free from defects in material and workmanship, and shall carry a manufacturer’s warranty of 10 years.