Fan Coil Unit System for HVAC

This article describes the minimum requirements for fan coil units, their accessories and controls.

Fan Coil Unit System for HVAC

Fan Coil Unit System for HVAC

Fan Coil Unit System for HVAC

fan coil unit (FCU), also known as a Vertical Fan CoilUnit (VFC), is a simple device consisting of a heating and/or cooling heat exchanger or ‘coil‘ and fan. It is part of an HVAC system found in residential, commercial, and industrial buildings. Source By Wikipedia.

FCU Control Circuit

FCU Control Circuit

FCU Control Circuit

FCU Control Circuit Electrical Heating and Special Terminal Box With Relays and Fuse



1. Product data shall include certified dimension drawings, specialties and accessories for each unit type and configuration.

2. Shop drawings shall be submitted the following for each fan-coil unit type and configuration:

a. Wiring diagrams indicating power, signal and control wiring. Wiring diagrams shall differentiate between manufacturer installed and field installed wiri

b. Equipment schedules shall include rated capacities; shipping, installed, and operating weights; furnished specialties; and accessories.

3. Operation, installation and maintenance data shall be submitted for fan coil units to including operation, installation and maintenance manuals.

Quality Assurance

1. Electrical components, devices, and accessories shall be listed and labeled as defined in NFPA 70, Article 100, by a testing agency acceptable to authorities having jurisdiction, and marked for intended use.

2. Fan coil units shall be tested and rated in accordance with ARI 440.

3. Fan coil units coils shall be tested in accordance with ASHRAE 33.


1. Fan coil chassis shall be galvanized steel, with flanged edges.

2. Cabinet shall be galvanized steel with removable panels.

3. Vertical unit front panels shall be removable, galvanized steel, with integrally stamped or galvanized steel discharge grilles and channel formed edges and with insulation on back of panel.

4. Horizontal unit bottom panels shall be fastened to unit with cam fasteners and hinge and attached with safety chain with integrally stamped or cast aluminum discharge grilles.

5 Cabinet finish shall be bonderized, phosphatized, and flow coated with baked on primer with manufacturer’s standard paint unless project requirements dictate an alternate finish.

6. Drain pans shall be galvanized steel, with connection for drain. Drain pan shall be insulated with polystyrene or polyurethane insulation. Drain pan shall be formed to slope from all directions to drain connection.


Coil section insulation shall be 25 mm duct liner complying with ASTM C 1071 and attached with adhesive complying with ASTM C 916. Insulation and adhesive fire hazard classification shall have a maximum flame spread rating of 25 and smoke developed rating of 50 when tested according to ASTM E 84.

Water Coils

Hot and chilled water coils shall be copper tube, with mechanically bonded aluminum fins spaced no closer than 2.5 mm and with manual air vent. Coils shall be rated for a minimum working pressure of 2068 kPa and a maximum entering water temperature of 135° C.

Direct Expansion Refrigerant Coils

Refrigerant coils shall be copper tube, with mechanically bonded aluminum fins spaced no closer than 2.5 mm and rated for a minimum working pressure of 2068 kPa.

Electric Resistance Heating Elements

a. Heating elements shall be nickel chromium heating wire, free from expansion noise and 60 Hz hum, embedded in magnesium oxide insulating refractory and sealed in high mass steel or corrosion resistant metallic sheath with fins no closer than 4 m Element ends shall be enclosed in terminal box. Fin surface temperature shall not exceed 288° C at any point during normal operation.

b. Circuit protection shall be provided by one time fuses in terminal box for overcurrent protection, air flow switch and limit controls for overtemperature protectio


Fan coil fans shall be centrifugal, with forward curved, double width wheels and fan scrolls made of galvanized steel or thermoplastic material; directly connected to or V belt driven from motor.

Fan motors for direct drive units shall be shaded pole or permanent split capacitor, multispeed with integral thermal-overload protection and resilient mounts.

Motors for belt drive units shall be open dripproof with hinged mount and adjustable motor pulley.


Refer to SES H01-E01 for filter media requirements.

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