Whirlpool RH8300XLS manual L-I

These Guidelines are to insure adequate ventilation for an indoor Electric Grtll. Indoor electric grills produce more smoke than normal cooking and requires at least 410 CFM to provrde

adequate ventilation. Less stringent ventilating requirements can deviate from these recommendations.

HORIZONTAL VENTING

Figure two on page two shows a direct drscharge to the outside through a wall rain cap. Due to the lower CFM rating in this venting posrtion. duct must be ltmited to a maximum of 2 feet of 3% x 10 inch duct capped with a wall rain cap with a free discharge area of at least 66 inches square. There should be no

bends in the connecting’duct between the hood and the wall rain cap.

Figure Sshows an installation requiring more duct length. A transition to round is used as close to the hood as possible t0 eliminate the restriction caused by the 3% x 10 duct. 4S” bends should be used instead of 90° bends wherever possible.

VERTICAL VENTING:

figure one on page two shows an installation using 3 feet of 3% x 10 inch duct terminating in a roof rain cap. In table one we see that 3 feet of 3% x 10 inch duct is the maximum length of 3% x 10 inch duct recommended.

For example, if the straight lengths of duct in Fig 9 total 9 ft. the elbow is 45O and the roof rain cap has 113 in2 free area. choose the duct size required. The 45i” elbow can be approximated by dividing the equivalent duct lengths in Table2 by two.

Since we already have 9 ft. of straight duct, Tdble 1 tells us that 7’ dia. is too small. So we try 8” dia.

9 ft. Straight Duct

6 ft. Equivalent straight length of 45O elbow (8” Dia.) 15 ft.

Fifteen feat is over the maximum of 13 ft. for 8” dia. duct, so 8” duct is to small.

Move to 9” dia. duct and run through the calculations again.

9 ft. Straight Duct.

7 ft. Equivalent straight length of 9” dia. duct for 45O elbow. 16 ft.

Sixteen feet is under the maximum of 25 ft. for 9” dia. duct, SO9” duct is a good choice.

. I

							FIGURE		9
				TABLE		I
I-G-l-I			Vertical		Venting
		3% x	10”	7”	dia.	8”	dia.	9”	dta.	10” di;
Size	1
Max.	I
IDuct				I		I		I		I
Length		3			7		13		25	40
(Feet1

Table I shows the maximum length of duct to be

used in conjunction			with a	roof	rain	cap having a
free area of 113 it-P.
			TABLE	2
	Duct			Equivalent			length	of
	Size		straight		duct	of same		dia.
	7”	dia.			11		ft.
	0”	dia.			12		ft.
9w	9”	dia.			14		ft.
	10”	dia.			16		ft.
Elbow

		CFM vs. DUCT	LENGTH
		Equivalenf Duct	Length	(ft.)
Static		3-X x 10 &act.	7”	dia.		9” dia.
Pressure	CFM				6” dia.
.06	460	4	a.5		17	30
.lO	440	7	16.0		31	55.5
.15	417	12	25.0		50	da
.20	390	18		40	77	142
.2s	355	26		61	104
,275	330	34		73	145
.30	250	65		136
.35	180	140

NOTE: The above table is based on vertical discharge. The values in this table are for duct length only and do not account for static pressure loss through roof mounted rain caps.

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