WW-F-2743 Furnaces, Warm Air and Heaters, Unit, Forced Air Circulation, Oil - and Gas FiredThis specification covers self-contained, forced-circulation, air heating units designed to distribute warm air for heating purposes either through a duct system for central furnaces or by direct diffusion for unit heaters.

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WW-F-2743A

a. For group 1 units; in accordance with DOE 10 CFR, Part 430, subpart B, appendix N or

O as applicable, for the AFUE.

b. For group 2, and group 3, and type I units, in accordance with UL 727, UL 731, UL 795, ANSI Z21.47, and ANSI Z83.8, as applicable.

4.4.5 Control tests. In addition to the tests of 4.4.1 through 4.4.4, the following controls on group 3 first article shall be checked, as applicable, to verify compliance with the applicable requirements of this specification and of referenced standards:

a. Programming sequence control. b. High-low-off control.

c. On-off control.

4.5 Quality conformance tests. The contractor shall have an established test system which shall ensure compliance with the requirements of the specification and of the referenced standards. The system shall include the methods, procedures, controls, records, and maintenance of the system to provide verification for the certifying agency of compliance with the requirements of this specification and of the reference standards and has been found mutually acceptable to the contractor and the certifying agency.

5. PACKAGING

5.1 Packaging requirements. The preservation, packing, and marking shall be as specified in the contract or order.

6. NOTES

(This section contains information of a general or explanatory nature that may be helpful, but is not mandatory.)

6.1 Intended use. Central furnaces are intended for installation in family housing or nonfamily housing structures primarily to supply heated air through a sheet metal duct system. Type I furnaces of the upflow style shall be suitable for alcove or closet installation in residential structures. Type I furnaces of the horizontal style shall be suitable for alcove installation in residential structures. Unit heaters are intended primarily for installation in such nonfamily structures as warehouses, industrial shops, auditoriums, hangars, and gymnasiums where warm air will be directly diffused into the space in which the heater is located. Downflow furnaces can be used to an advantage with under-floor duct systems in structures having no basements for central- furnace location. Downflow furnaces are also referred to as counterflow units since the heated-air path runs in a direction counter to the flue gas passage.