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)