Greenheck Fan PN 458294 manual fpm 423.0 cfm

High Velocity Cartridge Filters

A. Exhaust

With all the filters in place, determine the total hood exhaust volume with a shortridge meter as follows:

1.All cooking equipment should be on. If the hood has internal short circuit make-up air, it should be turned off.

2.Measuring Velocities

•Set up the shortridge meter. Leave all holes of Velgrid open. Do NOT tape over holes that are not over openings. The conversion factor takes this into account.

•Position the grid over each filter as shown.

•Take velocity readings for each filter.

3.*Calculate each filter’s volumetric flow rate by summing the flow rate of each individual filter in the hood.

4.*Calculate the total hood’s volumetric flow rate by summing the flow rate of each individual filter in the hood.

*Note: For best accuracy multiply the velocity of each filter by

its conversion factor and sum the flow rates. Averaging the velocity measured for all filters may cause error.

Nominal Filter Size (H x L)		Imperial	Metric
Inches	Millimeters	Conversion Factor	Conversion Factor
16 x 16	400 x 400	1.22 ft2	.113 m2
16 x 20	400 x 500	1.67 ft2	.155 m2
20 x 16	500 x 400	1.21 ft2	.112 m2
20 x 20	500 x 500	1.50 ft2	.139 m2

Example: Measured velocities for 20 x 20 filter = 282 fpm (5157 m/hr)

Flow rate for one filter	=	Conversion	x	Average
		Factor		Velocity
(Imperial)	=	1.50	x	282 fpm	=	423.0 cfm
(Metric)	=	.139	x	5157 m/hr	=	717 m3/hr

Total hood flow rate =	(Filter 1 Flow Rate) +	… + (Filter X Flow Rate)
=	423.0 + 421.8 + 420.7 + 418.2 = 1683.7 cfm
=	717 + 717 + 715 + 711	= 2860 m3/hr

Fig. 29

1/2 width

1/2 height

Fig. 30

21 Proximity Hood

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