Dwyer Series HFO In-Line Flow Alarm

Latching Alarm Capabilities, For Air, Water or Caustic Fluids, Unrestricted Mounting

The Series HFO Flow Alarm provides continuous monitoring and control of flow rate levels. The flow alarm can be configured to open or close a contact for an increasing or decreasing set point. The unit includes two 10A SPDT limit switches with field adjustable alarm settings. Integral direct reading scale provides local indication of flow rate. The flow alarm is designed to mount in any orientation and does not require inlet or outlet straight plumbing. The Series HFO is constructed with a rugged cast aluminum NEMA 4X (IP65) enclosure for installation outdoors or in harsh environments. Dimensional Information

APPLICATIONS
Monitoring flow in chemical processing, waste water processing, lubrication systems, process control, solar systems, drain lines and pump testing.

SPECIFICATIONS

Service: Compatible gases or liquids.
Wetted Materials:
Body: Aluminum, brass or 304 SS.
Seals: Buna-N or Viton®.
Magnet: Teflon® coated Alnico®.
Other Internal Parts: 304 SS.
Viscosity: 500 SSU.
Temperature Limits: 240°F (116°C).
Pressure Limits: Aluminum Body: 600 psig (41 bar); Brass Body: 3500 psig (240 bar); 304 Stainless Steel Body: 6000 psig (413 bar).
Enclosure Rating: NEMA 4X (IP65).
Accuracy Measuring: ±4% FS over entire range; ±2.5% over center third of the measuring range.
Repeatability: ±1% of full scale.
Switch Type: SPDT, 10A @ 250 VAC; 0.5A @ 125 VDC (resistive).
Shipping Weight: 1/4 to 1/2" female NPT Models: 3 lb (1.4 kg); 3/4 to 1" female NPT Models: 4.5 lb (2.0 kg); 1-1/2" female NPT Models: 12 lb (5.4 kg).

Series HFO In-Line Flow Alarms-Aluminum Body for Air or Other Non-corrosive Gases: 600 psig (41 bar)

Model Number	Connection Size	Range, Air, SCFM
HFO-21112	1/4" female NPT	2-12
HFO-21122	1/4" female NPT	2-22

Series HFO In-Line Flow Alarms-Brass Body for Water Based Fluids (non-steam): 3500 psig (240 bar)

Model Number	Connection Size	Range, Water, GPM (LPM)
HFO-22205	1/2" female NPT	0.5-5.0 (1-19)
HFO-22315	3/4" female NPT	2-15 (7.5-55)
HFO-22320	3/4" female NPT	2-20 (7.5-75)
HFO-22435	1" female NPT	5-35 (19-130)
HFO-22550	1-1/2" female NPT	5-50 (19-189)

Series HFO In-Line Flow Alarms-304 Stainless Steel Body for High Pressure Fluids: 6000 psig (413 bar)

Model Number	Connection Size	Range, Water, GPM (LPM)
HFO-23202	1/2" female NPT	0.2-2.0 (0.75-7.5)
HFO-23210	1/2" female NPT	0.5-10 (1.9-38)