The flow switch responds to pressure exerted on the fluid paddle by the flowing fluid. A range adjustment screw adjusts the rate of the flow that is required to activate the switch. See Table 1 through Table 1 for flow rates.
The red terminal is the Common. Red to yellow closes on flow increase. Red to blue closes on flow decrease.
Figure 1. F261 control switch action
GPM (m3/hr) required to activate switch for pipe size (in.) | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
1 | 1-1/41 | 1-1/21 | 2 | 2-1/22 | 3 | 43 | 53 | 63 | 83 | ||
Minimum adjustment | Flow increase (Close R to Y) | 4.20 (0.95) | 5.80 (1.32) | 7.50 (1.70) | 13.7 (3.11) | 18.0 (4.09) | 27.5 (6.24) | 65.0 (14.8) | 125 (28.4) | 190 (43.2) | 375 (85.2) |
Flow decrease (Close R to B) | 2.50 (0.57) | 3.70 (0.84) | 5.00 (1.14) | 9.50 (2.16) | 12.5 (2.84) | 19.0 (4.32) | 50.0 (11.4) | 101 (22.9) | 158 (35.9) | 320 (72.7) | |
Maximum adjustment | Flow increase (Close R to Y) | 8.80 (2.0) | 13.3 (3.02) | 19.2 (4.36) | 29.0 (6.59) | 34.5 (7.84) | 53.0 (12.0) | 128 (29.1) | 245 (55.6) | 375 (85.2) | 760 (173) |
Flow decrease (Close R to B) | 8.50 (1.93) | 12.5 (2.84) | 18.0 (4.09) | 27.0 (6.13) | 32.0 (7.27) | 50.0 (11.4) | 122 (27.7) | 235 (53.4) | 360 (81.8) | 730 (166) |
GPM (m3/hr) required to activate switch for pipe size (in.) | |||||
---|---|---|---|---|---|
4 | 5 | 6 | 8 | ||
Minimum adjustment | Flow
increase (Close R to Y) |
37.0 (8.40) | 57.0 (12.9) | 74.0 (16.8) | 205 (46.6) |
Flow
decrease (Close R to B) |
27.0 (6.13) | 41.0 (9.31) | 54.0 (12.3) | 170 (38.6) | |
Maximum adjustment | Flow
increase (Close R to Y) |
81.0 (18.4) | 118 (26.8) | 144 (32.7) | 415 (94.3) |
Flow
decrease (Close R to B) |
76.0 (1.93) | 111 (25.2) | 135 (30.7) | 400 (90.8) |
Figure 2. Pressure drop against flow rate for sample F261 Series Low-Flow
Switches
Note: This chart is
correct for F261KEH-V01C, F261MEH-V01C, F261KFH-V01C, F261MFH-V01C low-flow
switches.
Pipe size | ||||
---|---|---|---|---|
1/2 in. x 1/2 in. Female NPTF4 | 3/4 in. x 3/4 in. Female NPTF5 | 3/4 in. x 3/4 in. Female NPTF6 | ||
Minimum adjustment | Flow
increase (R to Y closes) |
1.30 (4.92) | 2.00 (7.57) | 10.90 (41.26) |
Flow
decrease (R to B closes) |
0.60 (2.27) | 0.60 (2.27) | 7.20 (27.25) | |
Maximum adjustment | Flow
increase (R to Y closes) |
2.60 (9.84) | 3.60 (13.63) | 17.00 (64.35) |
Flow
decrease (R to B closes) |
1.25 (4.73) | 1.30 (4.92) | 14.20 (53.75) |
1 Values for a 2 in. paddle
trimmed to pipe.
2 Values for a 3 in. paddle
trimmed to fit pipe.
3 Values calculated for a
factory-installed set of 1, 2, and 3 in. paddles.
4 F261KEH-V01C,
F261MEH-V01C
5 F261KFH-V01C,
F261MFH-V01C
6 F261KFH-V02C (designed for
steam applications)