The Problem: Low-Flow Damage
Cooling water systems depend on continuous flow to transfer heat away from process equipment. When flow drops below the minimum required — due to pump failure, valve closure, fouling, or air entrainment — heat exchangers overheat, tube bundles warp, and chiller compressors seize.
A PEECO flow switch installed in the cooling water supply or return line detects this low-flow condition and triggers an alarm or shuts down the protected equipment before damage occurs.
Series Selection
N Series — Non-Hazardous Locations
Most cooling water applications in mechanical rooms, HVAC plants, and power generation auxiliary systems are non-hazardous. The N Series NEMA 4X weatherproof housing handles these environments at pressures up to 600 PSI.
E Series — Hazardous Locations
When cooling water lines run through classified areas (e.g., near fuel oil systems or chemical storage), specify the E Series explosion-proof housing (Class I, Division 1, Group D).
Installation Tips
- 1Install on a horizontal pipe run with the switch body on top (12 o'clock position) to prevent sediment accumulation on the paddle.
- 2Maintain 10 pipe diameters of straight run upstream and 5 diameters downstream of the switch to ensure stable flow profile.
- 3For systems with variable-speed pumps, verify the minimum actuation flow rate against the lowest expected pump speed.
- 4In open cooling tower circuits, consider a strainer upstream to protect the paddle from debris.
- 5If the cooling water contains suspended solids or scale-forming minerals, specify a stainless steel body (316SS) for corrosion resistance.
Typical Specification
| Line Size | 1″ – 12″ (most common: 2″ – 6″) |
| Pressure | Up to 150 PSI (typical cooling water) |
| Temperature | 40°F – 200°F (standard paddle) |
| Media | Water, treated water, glycol solutions |
| Body Material | Carbon steel (standard) or 316SS |
| Housing | NEMA 4X (N Series) or Explosion Proof (E Series) |
| Micro-Switch | SPDT 15A 125-250 VAC (standard) |