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, and
7. gas piping.

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 an back side of unit providing full access to every part of the unit.

Blower capacity shall be _____ CFM at 70 degrees F standard air, ____ external static press.

External Static: The sum of duct loss plus duct component static- Example: louvers, diffusers. All blowers shall be tested and set at rated speed after being installed in the factory-assembled unit.

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 aluminum 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 15 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-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 design for Variable Air Volume capabilities.

1. pilot-gas shut-off valve 5. main-gas regulator 2. pilot-gas regulator 6. two solenoid valves 3. pilot-gas valve 7. modulating-gas valve 4. main-gas shut-off valve 8. burner

All gas manifold components shall be piped and wired at the factory.

high-gas pressure regulator

1. motor starter with adjustable overloads 5. main-gas regulator 2. air-flow safety switch 6. two solenoid valves 3. electronic flame-safety relay 7. modulating-gas valve 4. high-temperature limit switch 8. burner 9. Adjustable burner ON/OFF inlet air ductstat to shut off burner when inlet air is sufficiently warm to maintain space temperature. 10. Non-Fused Disconnect. 11. Casing insulation shall be 1" x 1.5# density with a foil face.

1. Adjustable low temperature blower-safety control with bypass timer to shut down unit, if discharge temperature drops below setting.
2. Proof-of-closure switch to energize the main-burner circuit only if the motorized gas valve is in a closed position.

1. 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 shall be made to guarantee the absence of noticeable vibration at design air velocities. Damper blades to be mounted on friction-free synthetic bearings. Damper edges shall have PVC coated polyester fabric mechanically locked into blade edge. Jamb seals to be flexible metal, compression type.
    
2. 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 (insulated) (uninsulated) constructed of G-90 galvanized steel with filter supported by internal slides and with removable access panels. Filters shall be provided in a filtered intake.

   
    
3. Fresh-Air Inlet Hood: Shall be constructed of G-90 galvanized steel with birdscreen.
    
4. Curb: 20" curb shall be constructed of 18 ga G-90 galvanized steel as a completed welded assembly.

Maxitrol Series 14 with room overide: For building-exhaust air replacement and auxiliary-space heating to maintain a constant supply-air discharge temperature. A room override thermostat raises discharge set-point for more heat to maintain room temperature. Discharge temperature probe and room-override thermostat modulate burner flame. Optional SUMMER-OFF/WINTER selector switch and exhaust-system interlock control heater-blower operation. Supplied with optional remote-control panel with temperature-selection dial, SUMMER-OFF/WINTER selector switch and room-override thermostat.

Maxitrol Series 44: For building exhaust-air replacement with modulated space-temperature control. A modulating space thermostat adjusts burner flame to maintain discharge-air temperature to compensate for changing building heat losses or gains. High- and low-discharge air sensor probes limit maximum and minimum discharge-air temperatures. The optional SUMMER-OFF/WINTER selector switch and exhaust-system interlocks control heater-blower operation. Supplied with optional remote-control panel with SUMMER-OFF/WINTER selector switch and a modulating-room thermostat.

Unit(s) shall be complete with all items such as relays, starters, switches, safety controls, conduit and wire as previously mentioned, and as required for proper operation. All factory-mounted controls shall be factory prewired to the unit control panel.