COMMERCIAL KITCHEN VENTILATION |
www.captiveaire.com |
Direct Fired Heater
Model AD Specification
Description
A Direct-fired gas heating and ventilating unit(s), as indicated on the drawings shall be furnished. Unit(s) shall be tested in accordance with ANSI Standard Z83.4a-2001/CSA 3.7a-2001, and shall bear the ETL label. Orientation shall be horizontal, down or side discharge. Unit(s) shall be factory assembled, tested and shipped as a complete packaged assembly, for indoor or outdoor mounting, consisting of the following:
1.Gas burner
2.Centrifugal blower (forward-curved double width/double inlet);
3.Motor starter with thermal overload protection
4.Motor and drive assembly
5.Fuel burning and safety equipment
6.Temperature control system
7.Gas piping
Construction
Housing: Unit housing shall be constructed of 20 Gauge G-90 galvanized steel. The wall panels and roof panels shall be fabricated by forming double-standing, self-locking seams that require no additional support. The floor and wall panels shall be caulked air tight with a silicone caulk. All casing panels shall be attached with sheet metal screws or rivets, which can be removed to field service large components. The unit base shall be suitable for curb or flat mount. Housing construction should be suitable for outdoor or indoor installation.
An observation port shall be located on the exterior of the unit for observation of the main flame and pilot flame. All controls, gas valves, modulating controls and electrical components shall be mounted within the burner vestibule. The burner vestibule shall be an integral part of the unit and not extend outside the exterior casing of the unit and not exposed to the main air stream.
The vestibule full-size door shall provide easy access to controls and gas-train components. Blower door shall provide easy access to blower, motor and drives. Access doors shall be provided on both front and backside of unit providing full access to every part of the unit.
Internal ridged board 1" x 1.5” foil face installation shall be installed on roof, walls and base of casing.
Base: The base shall be constructed of galvanized steel for improved rigidity. Base shall be structurally reinforced to accommodate the blower assembly and burner.
Blower: Blower(s) shall be forward-curved, centrifugal, Class I or II (depending on application requirements), double width, double inlet, constructed G-90 galvanized steel. Unit shall have a heavy-duty, solid-steel shaft. Wheels shall be balanced in two planes and done in accordance with AMCA standard 204-96, Balance Quality and Vibration Levels for Fans. The wheel blades shall be aerodynamically designed to minimize turbulence, increase efficiency and reduce noise. The wheel blades shall be securely attached to the wheel inlet ring. The wheel shall be firmly attached to the fan shaft with setscrews and keys. The blower assembly shall be isolated from the fan structure with vibration isolators.
Blower capacity shall be _____ CFM at 70 degrees F standard air, ____ external static press.
External Static is the sum of duct loss, plus duct component static. All blowers shall be tested and set at rated speed after being installed in the factory-assembled unit.
COMMERCIAL KITCHEN VENTILATION |
www.captiveaire.com |
Motor and Motor Compartment: Motors shall be heavy-duty ball bearing type and furnished at the specified voltage, phase and enclosure. Motor mounting plate shall be constructed of heavy gauge galvanized steel and shall be designed to provide easy adjustment of the belt tension. Blower motor shall be suitable for operation on
_______ volts, _______ cycle, _____ phase power. Blower motor shall be a ______________________ HP motor, Open Drip Proof.
Shaft and Bearings: Shafts shall be precision ground and polished. Heavy duty, pre-lubricated bearings shall be selected for a minimum (L50) life in excess of 200,000 hours of operation at maximum cataloged operating speed. They shall be designed for, and individually tested, specifically for use in air handling applications.
Belts and Drives: Belts shall be oil and heat resistant, non-static, grip-notch type. Drives shall be cast type, precision machined and keyed, and secured attached to the fan and motor shafts. Fan operating speed shall be factory set using adjustable pitch motor pulleys. Blower drives shall be fully adjustable. All drives shall be a minimum of 2 grooves above 2 HP.
Burner: The gas burner shall be a direct-fired, draw-through type, sized to provide an output of ________
BTU/hr using natural or propane gas at an inlet-supply pressure to the unit of _____ inches water column (7" w.c. minimum).
The burner shall be capable of heating the entire air supply from _____F° to _____F° ( ______ degrees F temperature rise). The burner shall burn over its entire length at all times when the system is in operation.
The burner shall have non-clogging, 4302B stainless-steel combustion baffles attached to a ductile cast-iron gas-supply section with no moving parts to wear out or fail. The burner shall be capable of 92% combustion efficiency with a maximum turndown ratio of 30 to 1.
The gas burner shall be furnished with a pilot package arranged so that the pilot flame lights the burner with instantaneous ignition. Pilot assembly includes a flame rod, spark rod and pilot, which is automatically ignited by a 6,000 volt ignition transformer. A flame-rod rectification system shall be used to prove pilot and main flame.
Rear access doors or a removable lid will provide complete access to burner and pilot assembly.
Burner profile plates shall be self-adjusting to operate across the complete CFM range of each model heater. Every unit shall be designed for Variable Air Volume capabilities.
Gas Equipment
All gas equipment should conform to local code requirements. All gas manifold components shall be piped and wired at the factory.
Components include:
∙Pilot gas shut-off valve
∙Pilot-gas regulator
∙Pilot-gas valve
∙Main - gas shut-off valve
∙Main - gas regulator
∙two solenoid valves
∙Modulating - gas valve
∙Burner
Optional: High-gas pressure regulator
Line and Manifold pressure gauges come standard on the unit and are installed at the factory before shipment. The Line pressure gauge will ensure proper pressure from the incoming gas line and is capable of measuring from 0 to 35” wc. The Manifold pressure gauge is installed after the combination gas valve to ensure proper pressure into the burner and is capable of measuring -5 to 15” wc. During startup, the Manifold pressure gauge will also help to set high and low fire
COMMERCIAL KITCHEN VENTILATION |
www.captiveaire.com |
on the unit.
Safety Controls
Standard Components include:
∙Motor starter with adjustable overloads
∙Air-flow safety switch
∙Electronic flame-safety relay
∙High-temperature limit switch
∙Main-gas regulator
∙Two solenoid valves
∙Modulating gas valve
∙Burner
∙Adjustable burner ON/OFF inlet air duct-stat to shut off burner when inlet air is sufficiently warm to maintain space temperature
∙Non-Fused Disconnect
∙Casing insulation shall be 1”x1.5” density with a foil face
Optional Components include:
∙High gas-pressure switch to open circuit to electronic flame safety relay, if gas pressure is too high
∙Low gas-pressure switch to open circuit to electronic flame safety relay, if gas pressure is too low
∙Adjustable low temperature blower safety control with bypass timer to shut down unit, if discharge temperature drops below setting
∙Proof of closure switch to energize the main burner circuit only if the motorized gas valve is in a closed position
Accessories
Inlet Dampers: Manufacturer shall provide and install on unit, when possible, a two-position, motor-operated damper with internal end switch to energize the blower-starter circuit, when damper is 80% open. Blades shall be a maximum of 6" wide 16-gauge G-90 galvanized steel and shall be made to guarantee the absence of noticeable vibration at design air velocities. Damper blades are to be mounted on friction-free synthetic bearings. Damper edges shall have PVC coated polyester fabric mechanically locked into blade edge. Jamb seals used are flexible metal, compression type.
Filters: The filters shall be (2") thick, aluminum mesh, coated with super-filter adhesive. Aluminum-mesh filters shall have aluminum frames with media to be layers of slit and expanded aluminum, varying in pattern to obtain maximum depth loading. Washable 2" filters shall be enclosed in two-piece, die-cut frame with diagonal supports. Frame shall be constructed of heavy-duty beverage board. Filter media is supported on the air leaving side by a metal grid.
Filter Section: shall be either insulated or non-insulated constructed of G-90 galvanized steel with filters supported by internal slides and with removable access panels. Filters shall be provided in a v-bank arrangement.
Fresh-Air Inlet Hood: Shall be constructed of G-90 galvanized steel with bird screen.
Fresh-Air Inlet Hood/Filter Combination: Shall be constructed of G-90 galvanized steel with bird screen and (2") cleanable filters supported by internal slides mounted in the inlet face of the hood.
Discharge Diffusers: Shall be constructed of G-90 galvanized steel with horizontal and vertical blades capable of four-way diffusion.
Loading...