Figure 1. Flow direction for vertical mounting
Important: Do not use the F261 flow switch in a vertical pipeline with a downward
flow.
Mount the F261 flow switch in a horizontal pipeline or a vertical pipeline with upward fluid flow. When you mount the switch in a vertical pipe with an upward flow, it trips at a slightly higher flow than in Table 2 and Table 3, due to the effect of gravity on the switch mechanism.
Mount the F261 flow switch in a section of pipe where there is a straight run of at least five pipe diameters from the nearest elbow, valve, or other pipe restriction. See Figure 2.
Figure 2. Required piping distance
| Callout | Description |
|---|---|
| A | Distance of at least five pipe diameters from the nearest elbow, valve, or other pipe restriction |
| B | Flow |
| C | Tee or welded half-coupling |
When you mount the flow switch on a horizontal pipe, mount the flow switch within 60 degrees of vertical. See Figure 3.
Figure 3. Correct flow switch angle
Note: Do not subject the flow switches to water hammer. Use a suitable water hammer
arrester if a fast-closing valve is located downstream of the switch. See Figure 4.
Figure 4. Water hammer arrester location
| Callout | Description |
|---|---|
| A | Water hammer arrester |
| B | Flow |