Greenheck Fan 240XP-CUb manual Preliminary Selections, Stability Considerations

Preliminary Selections

At this point we know the model, cfm and Ps. With this information we can refer to the GB performance charts to determine the sizes available to move 2400 cfm against 0.50 in. Ps.

In our case, all of the criteria can be met by more than one size of a particular model. When this occurs, choose the size that provides the greatest airflow range about the desired cfm. For example, many direct drive fans have three speeds. If possible, choose a size that uses the middle rpm. This will allow some final system adjustment if the actual cfm the job requires is somewhat higher or lower once the fan is installed. Belt driven fans have adjustable motor pulleys which allow the fan speed to be varied. With belt drive units, avoid

selecting near the maximum rpm of a size to allow for final adjustments if necessary.

There are four GB sizes to choose from in the QD catalog. These sizes along with their performance data are in the table below.

Model and	Performance Box Data			RPM
Size	CFM	Sones	Bhp
GB-141	2556	16.8	.76	1545
GB-161	2614	13.5	.53	1100
GB-180	2375	8.6	.35	810
GB-200	2493	7.8	.40	700

Stability Considerations

Whenever there is more than one size to choose from, it is not recommended to select from the performance box in the far right column for any given rpm unless the Ps is known to be accurate. For example, the GB-200 selection (see table below) of 2493 cfm at 0.50 in. Ps is the far right selection at 700 rpm.

The next box to the right (0.625 in. Ps) is empty because the performance at that point is unstable. This means that 2494 cfm at 0.50 in. is marginally stable.

For more information on fan stability, contact Greenheck.

			Tip							STATIC PRESSURE / CAPACITY
MODEL	hp	RPM
				0.000		0.125		0.250		0.375		0.500		0.625		0.750			0.875		1.000
(rpm RANGE)			Speed
				Sone	Bhp	Sone	Bhp	Sone	Bhp	Sone	Bhp	Sone	Bhp	Sone	Bhp	Sone		Bhp	Sone	Bhp	Sone	Bhp
GB-141-5	1/2	1360	5207	2522		2433		2346		2258		2166		2062		1942			1792		1602
(1125-1360)				14.6	0.48	14.3	0.50	13.9	0.51	13.5	0.52	13.1	0.52	12.7	0.52	12.2	0.53		11.6	0.52	11.0	0.51
GB-141	3/4	1545	5915	2866		2787		2709		2634		2556		2475		2384			2286		2176
				17.6	0.71	18.0	0.72	17.4	0.74	17.1	0.75	16.8	0.76	15.9	0.77	14.9	0.77		14.8	0.77	14.7	0.78
		785	3416	2318		2104		1875		1587
GB-161-4	1/4			8.9	0.18	8.5	0.19	8.3	0.19	7.8	0.19
(634-865)		865	3764	2555		2359		2162		1932		1624
				10.6	0.24	10.1	0.25	9.7	0.26	9.4	0.26	8.8	0.25
		985	4287	2909		2737		2567		2382		2176		1914		1550
GB-161-5	1/2			13.4	0.35	12.7	0.36	12.3	0.37	11.9	0.38	11.5	0.38	10.9	0.37	10.2	0.35
(852-1100)		1100	4787	3249		3094		2943		2786		2614		2428		2197			1899
				15.3	0.48	14.7	0.50	14.1	0.52	13.8	0.53	13.5	0.53	13.0	0.53	12.5		0.52	12.0	0.50
		770	3729	2994		2833		2651		2427		2139		1700
GB-180-3	1/3			8.1	0.25	9.2	0.26	9.1	0.29	8.5	0.30	7.8	0.30	7.4	0.28
(618-810)		810	3923	3150		2997		2832		2624		2375		2053
				10.6	0.29	10.3	0.31	10.0	0.33	9.3	0.35	8.6	0.35	8.2	0.34
		900	4359	3500		3364		3219		3052		2858		2624		2347			1821
GB-180-5	1/2			12.7	0.40	12.4	0.42	12.1	0.44	11.3	0.46	10.5	0.48	10.2	0.48	9.8		0.47	9.2	0.43
(700-940)		940	4553	3655		3527		3388		3234		3052		2844		2601			2272
				13.6	0.46	13.4	0.47	13.1	0.49	12.3	0.52	11.4	0.54	11.0	0.55	10.6		0.54	10.1	0.52
		1000	4843	3888		3768		3638		3504		3339		3164		2952			2712		2387
GB-180-7	3/4			15.2	0.55	14.7	0.57	13.7	0.58	13.3	0.62	13.0	0.64	12.4	0.66	11.9		0.66	11.6	0.65	11.1	0.63
(764-1055)		1055	5109	4102		3989		3866		3741		3596		3432		3251			3050		2811
				16.2	0.65	15.7	0.67	14.9	0.68	14.4	0.72	14.0	0.74	13.5	0.76	12.9		0.77	12.7	0.77	12.4	0.77
	1	1185	5739	4607		4507		4400		4290		4179		4045		3900			3753		3575
				19.0	0.91	18.4	0.94	17.8	0.96	17.4	0.98	17.1	1.03	16.7	1.05	16.2		1.07	15.8	1.10	15.4	1.10
GB-180	11/2	1335	6465	5191		5102		5010		4912		4814		4715		4599			4474		4343
				22.0	1.31	22.0	1.33	21.0	1.36	21.0	1.37	21.0	1.41	20.0	1.47	19.9		1.49	19.5	1.51	19.2	1.54
	2	1460	7071	5677		5595		5514		5424		5335		5245		5155			5049		4938
				26.0	1.71	25.0	1.74	24.0	1.77	24.0	1.79	24.0	1.81	24.0	1.86	23.0		1.93	23.0	1.95	23.0	1.97
		700	3917	3873		3591		3307		2973		2493
GB-200-5	1/2			10.3	0.39	9.6	0.40	9.2	0.41	8.6	0.41	7.8	0.40
(512-770)		770	4308	4260		4013		3744		3477		3140		2643
				12.1	0.52	11.0	0.53	10.7	0.55	10.2	0.55	9.8	0.55	9.3	0.52

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