Dwyer Instruments HFO Series Operating Instructions

Series HFO Flow Alarms are typically used to
make or break a set of electrical contacts to
signal a limit setting. They may be used to turn
on a warning light, sound a bell or horn, or even
to shut down a process. The switches on the
flow alarm can be configured to open or close a
contact for an increasing or decreasing set
point. Decreasing flow set points may be
located anywhere in the lower 2/3 of the scale
while increasing set points may be located
anywhere in the upper 2/3 of the scale.
Note: Refer to Series HF In-Line Flow Monitor,
Bulletin F-55, "Installation and Operating
Instructions" for installation, operation, and
cleaning instructions for the basic flow monitor
cartridge (included). The following instructions
are specifically for the Series HFO Flow Alarm
switches.
PRESSURE DIFFERENTIAL VS. FLOW RATE
1/4˝ FEMALE NPT
DWYER INSTRUMENTS, INC.
P.O. BOX 373 • MICHIGAN CITY, INDIANA 46360, U.S.A.
Series HFO Flow Alarm
Specifications – Operating Instructions
1/2˝ FEMALE NPT
SPECIFICATIONS
Service: Compatible gases or liquids.
Wetted Materials: Body: Aluminum, brass or
304 SS; Seals: Buna-N or Fluoroelastomer;
Magnet: PTFE coated Alnico; Other internal
parts: 304 SS.
Viscosity Limit: 500 SSU.
Temperature Limits: 170°F (76°C).
Pressure Limits: See Chart.
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), 1/4 hp @ 250 VAC
(inductive); 3A @ 125 VAC "L" lamp load.
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).
3/4˝, 1˝ & 1-1/2˝ FEMALE NPT
Phone: 219/879-8000
Fax: 219/872-9057
Bulletin F-HFO
www.dwyer-inst.com
e-mail: info@dwyer-inst.com