Allied Air Enterprises A93UH, A95UH, 95G1UH, 92G1UH General Guidelines for Vent Terminations

Follow the next two steps when installing the unit in Non– Direct Vent applications where combustion air is taken from indoors and flue gases are discharged outdoors.

1.Use field-provided materials and the factory-provided air intake screen to route the intake piping as shown in figure 26 or 27. Maintain a minimum clearance of 3" (76 mm) around the air intake opening. The air intake opening (with the protective screen) should always be directed forward or to either side in the upflow position, and either straight out or downward in the horizontal position.

The air intake piping must not terminate too close to the flooring or a platform. Ensure that the intake air inlet will not be obstructed by loose insulation or other items that may clog the debris screen.

2.Use a sheet metal screw to secure the intake pipe to the connector, if desired.

General Guidelines for Vent Terminations

In Non–Direct Vent applications, combustion air is taken from indoors and the flue gases are discharged to the outdoors. The furnace is then classified as a non–direct vent, Category IV gas furnace.

In Direct Vent applications, combustion air is taken from outdoors and the flue gases are discharged to the outdoors. The furnace is then classified as a direct vent, Category IV gas furnace.

In both Non–Direct Vent and Direct Vent applications, the vent termination is limited by local building codes. In the absence of local codes, refer to the current National Fuel Gas Code ANSI Z223-1/NFPA 54 in U.S.A., and current CSA-B149 Natural Gas and Propane Installation Codes in Canada for details.

Position termination according to location given in Figure 28 or 29. In addition, position termination so it is free from any obstructions and 12" above the average snow accumulation.

At vent termination, care must be taken to maintain protective coatings over building materials (prolonged exposure to exhaust condensate can destroy protective

coatings). It is recommended that the exhaust outlet not be located within 6 feet (1.8 m) of a condensing unit because the condensate can damage the painted coating.

NOTE: If winter design temperature is below 32° F (0° C), it is recommended that the exhaust piping be insulated with 1/2" (13 mm), Armaflex or equivalent when run through an unconditional area. In extremely cold climate areas with temperature below 20° F (6.7° C) it is recommended that, 3/4" (19 mm) Armaflex or equivalent be used. Insulation on outside runs of exhaust pipe may be painted or wrapped to protect insulation from deterioration in accordance with the insulation manufacturers recommendation. Exhaust pipe insulation may not be necessary in some specific applications.

NOTE: During extremely cold temperatures, below approximately 20° F (6.7° C), units with long runs of vent pipe through unconditioned space, even when insulated, may form ice in the exhaust termination that prevents the unit from operating properly. Longer run times of at least 5 minutes will alleviate most icing problems. Also, a heating cable may be installed on exhaust piping and termination to prevent freeze-ups. Heating cable installation kits are available see unit specification sheets for part numbers.

IMPORTANT

Do not use screens or perforated metal in exhaust terminations. Doing so will cause freeze-ups and may block the terminations.

IMPORTANT

For Canadian Installations Only:

In accordance to CSA International B149 installation codes, the minimum allowed distance between the combustion air intake inlet and the exhaust outlet of other appliances shall not be less than 12 inches (305 mm).

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