Roberts Gorden BH50ST/EF BH55ST, BH35UT/EF Outside Combustion Air Supply, Air Supply Requirements

SECTION 11: VENTING

Figure 30: Individual Flue Connection Detail

	Fan Assembly
Fan Tube
	Nut
	Lockwasher
Screw
(Torque: 2 Nm
Flue Adapter	18 in lb)
Flue Pipe

Figure 31: Flue Connection Dimensions

C

End of Tube

A

Fan Tube Fan

B

Heater Model	Fan Model	A	B	C	Part Number
BH 15-30	Torin DSF-133-42	79 mm	95 mm	45 mm	C2374B
BH 35-50	AO Smith JF1G	89 mm	102 mm	51 mm	90710000

11.3 Outside Combustion Air Supply

Where necessary, clean air may be ducted into the burner box through an added spigot on the back of the burner box replacing the existing dust arrest baffle plate.

See Page 50, Section 11.1.3 for recommendations on duct length. Air duct should be as straight as possible. Do not use bends in excess of 45°. Consult the manufacturer if more than 2 x 45° offset bends are necessary. The fresh air duct must be self supporting.

11.3.1 Air Supply Requirements

When fresh air duct is used, follow one of these rules:

•The flue must penetrate the roof while fresh air can penetrate any wall. (See Page 52, Figure 33)

•The flue and fresh air supply must penetrate the same roof, at a minimum of 1 m apart. (See Page 52, Figure 33)

•The flue must penetrate 1 m higher than the fresh air inlet on the same wall. (See Page 52, Figure 33)

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