Holyoake HCV assemblies may be used to control temperature in the space served by one or many air diffusers. Systems may be designed for volume control by velocity reset at the assembly, or for static pressure control in response to variable orifice air diffusers.

Matching components provide re-heat, noise attenuation and balanced air distribution plenums.

With Holyoake HCV assemblies duct systems can be more simply designed with flexibility to accommodate subsequent tenancy changes.

The standard unit consists of an airflow measuring station and a multi-blade voluime control damper. Modules can be added such as hot water or electric heating banks, attenuators and multioutlet boxes. Units can be supplied with or without controls.

The HDC series provides full variable volume control in both the hot deck and cold deck of a dual duct system. The air flow rate can be varied between a regulated pre-set minimum and a regulated pre-set maximum.

At any system static pressure above the minimum required for signaling the controller, the flow rate anywhere in the operating range is pressure independent. For example, if the thermostat is calling for 0.5m3/s the HDC controls will hold the flow rate at 0.5 m3/s, regardless of fluctuations in system pressure between the minimum and 500 Pa.

In addition to pressure independent variable volume, the HDC controls provide numerous combinations of settings for hot-cold air mixture proportions.

The HDC control functions are the same as those described for the HCV single duct assembly on preceding pages. Standard construction includes a mixer-attenuator. Basic units without this component are available.

Flow averaging ∆P velocity sensors are standard. Single point sensing as required by some control types can be substituted where necessary.

Fan Assisted Variable Air Volume Control Assemblies (HFC) Holyoake fan assisted VAV terminals, both series and parallel types, have been designed to provide optimum performance with robust construction, minimum noise and maximum reliability.   The primary air element is identical to the HCV series air valve and mechanism, with extruded aluminium blades mounted in a steel liner, forming a high pressure chamber for ducted inlet air. A forward curved fan, directly driven by a multi-speed, resilient mounted single phase P.S.C. motor, is rigidly supported within the casing. All components are housed in a acoustically lined steel enclosure.