Flow Rate Table

Minimum flow rates required for actuation by H₂O & GN² (based on vertical installation on horizontal pipe runs). All switches tested at 100 PSI and 300 PSI with a 15A 125-250-480 VAC SPDT Micro-Switch.

I = Increasing Flow | D = Decreasing Flow | P = Pressure Drop in PSI

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— L/min

Line Sizes 1/4″ to 3/4″

Pipeline Size	Flow	GPM (H₂O)	Press Drop	SCFM (GN₂)	Press Drop
1/4" STD	INCREASING	1.174	4.72 PSI	6.62	1.54 PSI
	DECREASING	1.155	4.39 PSI	4.20	0.65 PSI
1/4" LOW FLOW	INCREASING	0.148	4.59 PSI	<0.05	0.43 PSI
	DECREASING	0.13	4.58 PSI	<0.05	0.425 PSI
1/2" STD	INCREASING	1.94	0.64 PSI	8.9	0.5 PSI
	DECREASING	1.66	0.60 PSI	8.0	0.5 PSI
1/2" LOW FLOW	INCREASING	0.22	0.7 PSI	<0.04	0.798 PSI
	DECREASING	0.20	0.7 PSI	<0.04	0.735 PSI
3/4" STD	INCREASING	3.14	0.06 PSI	13.9	0.07 PSI
	DECREASING	2.42	0.06 PSI	11.42	0.07 PSI
3/4" LOW FLOW	INCREASING	0.599	0.8 PSI	5.37	0.036 PSI
	DECREASING	0.599	0.8 PSI	4.67	0.036 PSI

Velocity Recommendations

Velocity	Modification Required
Under 7 FPS	Use Standard Unit
7 – 10 FPS	Paddle Shroud
Over 10 FPS	High Flow Configuration

Velocity Correction Factors

Specific Gravity	Multiplication Factor
.40	1.65
.45	1.55
.50	1.46
.55	1.39
.60	1.33
.65	1.27
.70	1.22
.75	1.17
.80	1.13
.85	1.10
.90	1.06
.95	1.03
1.00	1.00
1.05	.97
1.10	.95
1.15	.92

Installation Notes

All minimum actuation points are based on the switch being installed vertically (within 5° of vertical) in a horizontal pipe. Other installations must be called out at time of quotation. Switches will not work properly in turbulent flow — recommend a minimum of 10 pipe diameters of straight run in front of the switch and 5 pipe diameters after. All switches must be adjusted after installation unless a 3rd party calibration has been requested.

Installing a PEECO Flow Switch – Mount Diagram

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