HVAC Guide Specifications
Series Variable Air Volume Terminal UnitsFan-Powered
Size Range:
90 to 3900 cfm
Carrier Model Number (45J Units):
45JA (Analog Electronic Control)
45JC (CCN VAV Electronic Control [DDC, CCN])
45JD (BACnet VAV)
45JN (No Control or DDC by Others)
45JP (Pneumatic Control)
Part 1 — General
1.01 SYSTEM DESCRIPTION:
A. Fan-powered terminal unit shall be completelyfactory assembled and wired, with blower, blowermotor, mixing plenum and primary air dampercontained in a single unit housing.
B. The induced air fan shall operate continuouslyduring central system operation. Primary airflowcontroller shall compensate for central systempressure fluctuations. When room temperaturerequires maximum heating, the (PIC direct digitalelectronic) (analog electronic) (pneumatic) pressureindependent velocity controller maintains the minimumprimary airflow setting by modulating thedamper. The staged electric heating coil or hotwater coil, if supplied, is energized (activated). Asroom temperature begins to rise, the heating coil isdeenergized (deactivated). As room temperaturerises above the set point, the primary air damperwill modulate to maintain room temperature. Whenthe room temperature calls for maximum cooling,the velocity controller maintains the maximum primaryairflow setting. To prevent the fan/motor fromrunning in the backward direction, the unit inducedair fan shall be field wired so that it is electrically orpneumatically interlocked with the central systemfan.
1.02 QUALITY ASSURANCE:
A.Terminals shall be certified by use of the AHRIStandard 880 Certification Program and carry theAHRI seal.
B. The terminal unit shall be ETL listed as a completeassembly. All electrical components shall be ULlisted and installed in accordance with the NEC. Allelectrical components shall be mounted in sheetmetal control enclosures. Electrical connections shallbe single point.
1.03 DELIVERY AND STORAGE:
Units shall be stored and handled as per manufacturer’srecommendations.
Part 2 — Products
2.01 EQUIPMENT:
A. General:
Factory assembled, externally powered, horizontalfan powered terminal unit with blower, blowermotor, mixing plenum and primary air dampercontained in a single unit housing.
B. Unit Cabinet:
1. Constructed of 22 gage (20 gage optional) zinc-coatedsteel. All primary air inlet collars shallaccommodate standard flex duct sizes. Unitdischarge shall be rectangular, suitable forflanged duct connection.
2. Unit casing shall be lined with dual density,1/2-in. thick, 11/2 lb density fiberglass insulationthat meets UL 181 and NFPA 90A (1-in. thick,3 lb density optional).
3. (Optional) Foil Encapsulated Insulation:
Unit casing shall be lined with foil reinforced,wrapped edges, 1/2-in. or 1-in. thick, 11/2 lbdensity fiberglass insulation that meets UL 181and NFPA 90.
4. (Optional) Cellular Insulation:
Unit casing shall be lined with 3/8-in. thick,smooth surface, closed-cell elastometric thermalinsulation for fiber free application.
C. Damper Assembly:
The primary air damper assembly shall be constructedof heavy gage galvanized steel with solidshaft rotating in Delrin* bearings. Damper shaft shallbe marked on the end to indicate damper position.Damper blades shall incorporate a flexible gasket fortight airflow shutoff and operate over a full90 degrees.
D. Fan(s):
Fan shall be of the forward curve, centrifugal type.The fan motor shall be single speed, multi-voltage(120, 208/240, 277), 60 cycle, single phase,energy efficient design, permanently lubricated,using permanent split capacitor for starting and bespecifically designed for use with an SCR (fan speedcontroller). Motor must have thermal overloadprotection. The fan motor shaft shall be connecteddirectly to the fan and the entire fan assembly shallbe isolated from the unit casing to prevent transmissionof vibration.
E. Electrical Requirements:
Units shall have a single connection for power, andoperate on 120,208/240 or 277 vac (standard)single phase, 60 Hz power as shown on theequipment schedule. Units with three-phase electricheat shall be factory wired for single point performance(including 208/240 v 3-wire or 480 v4-wire). When specified and coordinated, units shallbe wired and shipped with proportionally connectedphasing.
F. Controls:
1. Units shall have pressure-independent pneumatic,electronic, or communicating controls,as specified, capable of maintaining requiredairflow set points ± 5% of the unit’s capacity atany inlet pressure up to 6 in. wg. Thecontrollers shall be capable of resetting betweenfactory or field-set maximum and minimum(>350 fpm inlet duct velocity) set points to satisfythe room thermostat demand.
2. Sensor Type:
a. The unit shall be equipped with an amplifiedlinear averaging flow probe located horizontallyacross the inlet. The sensor will providea differential pressure signal amplified toequal 3 times the velocity pressure with anaccuracy of at least ± 10% throughout therange of 350 to 2600 fpm inlet duct velocity,depending on the controller employed.
b. The unit shall be equipped with a four quadrantlinear cross sensor. This is a multi-pointcenter averaging, inlet flow sensor, availablefor use with pneumatic, analog electric anddigital electric control type units.
G. Special Features:
1. Electric Heating Coil:
a. Electric coils shall be supplied by the terminalunit manufacturer and shall be UL listed.Construct coil casing with minimum of 20gage zinc coated steel. Elements shall benickel chrome and supported by ceramicinsulators. The integral control panel shall behoused in a NEMA 1 enclosure, with hingedaccess door for access to all controls andsafety devices.
b. Electric coils shall contain a primary automaticreset thermal cutout and differentialpressure airflow switch for proof of airflow.(OPTIONAL) Electric coils shall include fusedor non-fused door interlocking disconnectswitch, mercury contactors, fuse block, dust-tightenclosure construction, all mountedand/or wired within the control enclosure.
2. Hot Water Coil:
Hot water coil casing shall be constructed withminimum 20 gage galvanized steel with flangeddischarge for attachment to downstreamductwork. Coils shall be factory installed on theterminal unit. Fins shall be rippled andcorrugated heavy gage aluminum, mechanicallybonded to tubes. Tubes shall be copper withminimum wall thickness of 0.016-in. and withmale solder header connections. Coils shall beleak tested to 400 psig. Number of coil rowsand circuits shall be selected to provideperformance as required by the plans. Coilperformance data shall be based on tests run inaccordance with AHRI Standard 410.
*Registered trademark of DuPont.