Fan Coil Unit | Pro Datum Inc

By: Pro Datum  09-12-2011
Keywords: Fan Coil Unit

Fan Coil Unit

It should be first appreciated that ‘Fan Coil Unit’ is a generic term that is applied to a range of products. Also, the term ‘Fan Coil Unit’ will mean different things to users, specifiers and installers in different countries and regions, particularly in relation to product size and output capability.

A fan coil unit may be concealed or exposed within the room or area that it serves.

An exposed fan coil unit may be wall mounted, freestanding or ceiling mounted, and will typically include an appropriate enclosure to protect and conceal the fan coil unit itself, with return air grille and supply air diffuser set into that enclosure to distribute the air.

A concealed fan coil unit will typically be installed within an accessible ceiling void or services zone. The return air grille and supply air diffuser, typically set flush into the ceiling, will be ducted to and from the fan coil unit and thus allows a great degree of flexibility for locating the grilles to suit the ceiling layout and/or the partition layout within a space. It is quite common for the return air not to be ducted and to use the ceiling void as a return air plenum.

The coil receives hot or cold water from a central plant, and removes heat from or adds heat to the air through heat transfer. Traditionally fan coil units can contain their own internal thermostat, or can be wired to operate with a remote thermostat. However, and as is common in most modern buildings with a Building Energy Management System (BEMS), the control of the fan coil unit will be by a local digital controller or outstation (along with associated room temperature sensor and control valve actuators) linked to the BEMS via a communication network, and therefore adjustable and controllable from a central point, such as a supervisors head end computer.

Fan coil units circulate hot or cold water through a coil in order to condition a space. The unit gets its hot or cold water from a central plant, or mechanical room containing equipment for removing heat from the central building’s closed-loop. The equipment used can consist of machines used to remove heat such as a chiller or a cooling tower and equipment for adding heat to the building’s water such as a boiler or a commercial water heater.

Fan coil units are divided into two types: Two-pipe fan coil units or four-pipe fan coil units. Two-pipe fan coil units have one (1) supply and one (1) return pipe. The supply pipe supplies either cold or hot water to the unit depending on the time of year. Four-pipe fan coil units have two (2) supply pipes and two (2) return pipes. This allows either hot or cold water to enter the unit at any given time. Since it is often necessary to heat and cool different areas of a building at the same time, due to differences in internal heat loss or heat gains, the four-pipe fan coil unit is most commonly used.

Depending upon the selected chilled water temperatures and the relative humidity of the space, it is likely that the cooling coil will dehumidify the entering air stream, and as a by product of this process, it will at times produce a condensate which will need to be carried to drain. The fan coil unit will contain a purpose designed drip tray with drain connection for this purpose. The simplest means to drain the condensate from multiple fan coil units will be by a network of pipework laid to falls to a suitable point. Alternatively a condensate pump may be employed where space for such gravity pipework is limited.

Speed control of the fan motors within a fan coil unit is effectively used to control the heating and cooling output desired from the unit. This is normally achieved by manually adjusting the taps on an AC transformer supplying the power to the fan motor. Typically this is adjusted at the commissioning stage of the building construction process and is therefore set for life. However alternative means of external speed control by electronic means through the BEMS can be provided if so required. Fan motors are typically AC type motors but more recently DC motors have been made available by some manufacturers, particularly in the UK, which do offer significant energy savings.

Keywords: Fan Coil Unit

Contact Pro Datum

Email - none provided

Print this page

Other products and services from Pro Datum


Sheet Metal Enclosure | Pro Datum Inc

Our standard NEMA enclosures and electrical enclosures come in styles such as wall mount, free standing, JIC and troughs. We can take your design and manufacture a quality NEMA-rated enclosure made to specification within 10 days. We design and manufacture custom styles that are compliant to NEMA standards UL listed. We can then finish it with silk screening or engraving. > Floor Mount NEMA Enclosures.


Products | Pro Datum Inc

We drive customer success through the use of formal operational audit programs, ISO standards and additional industry-specific certifications proven to reduce waste and costs while improving efficiencies. We work to earn your business every day, providing extensive design and engineering, supply chain management, manufacturing, logistics and post-manufacturing repair and warranty services.


Air Cleaner | Pro Datum Inc

There are lots of people who make the purchase, but don’t correctly use their air purifiers, if they even use them at all. Even if you should put a price tag on it, you’ll discover that you have numerous options. Another advantage to owning an air purifier will be the price of owning one. Many individuals believe that air cleaners cost too much money.


HVAC products | Pro Datum Inc

By the time you’re done reading, you should have a very good idea of how to go about changing your destiny for the better with a career in heating and cooling.Free HVAC Training. From the software available to the schools that have certification classes available, you are going to have the information you need for HVAC training and certification.


Lighting Fixture | Pro Datum Inc

All light fixtures have a fixture body, a light socket to hold the lamp and allow for its replacement—which may also have a switch to operate the fixture, and also require an electrical connection to a power source, often by using electrical connectors with portable fixtures. A light fixture, light fitting, or luminaire is an electrical device used to create artificial light and/or illumination, by use of an electric lamp.