Dwyer P1 User Manual

Piston-Type Flow Switches

Series P1

Installation . . .

Unless otherwise specified at time of purchase, units are calibrated in a vertical position, with lead wires up.
Install unit in piping system, using standard pipe fitting procedures. Be sure to keep thread sealing com­pound out of unit. Make sure that flow is in proper direction - marked "IN" and "OUT" on housing. See
wiring diagrams for electrical connections. CAUTION: See "Switch Ratings" before connecting power.

CAUTION: Flow settings for P1 series switches are normally calibrated using water @ +70°F on
increasing flow. If unit will be used to monitor liquids other than water, gas or air, Factory should have been
consulted at time of purchase for special calibration. All air/gas units are factory-calibrated using a special
piston. Water-calibrated units are not recommended for air/gas applications.

Specifications . . .

Wetted Materials
Housing
Piston
Brass Housing
Stainless Steel Housing
Spring
O-Ring
Other Wetted Parts
Pressure Rating
Operating
Proof
Burst
Operating Temperature
Brass or SS Piston
Polysulfone Piston
Repeatability
Set Point Accuracy
Set Point Differential
Switch*
Inlet/Outlet Ports
Electrical Termination

Polysulfone/Water - Brass/Oil or Air

-20°F to +300°F (-29°C to +148.9°C)

-20°F to +225°F (-29°C to 107.2°C)

No. 18 AWG, 24" L., Polymeric Lead Wires

Brass or 316 SS

316 SS

316 SS

®

Viton

Epoxy

1000 PSIG
2500 PSIG
5000 PSIG

1% Maximum Deviation

±10%

15% Max.

SPDT, 20 VA

1/4" NPT

* Switch Ratings

Max. Resistive Load

VA20Volts

0-30

120
240

Amps AC

.4
.17
.08

Amps DC

.3
.13
.06

Typical Wiring Diagram

A

C
B

Pin Connections for
Units with MS Receptacle

Dimensions . . .

Maintenance . . .

Accumulation of foreign debris should periodically be removed
from these switches. Occasional "wipe-down" cleaning when
excessive contamination is present is all that is normally
required. To clean: Remove unit from system and disassemble
as shown below. Clean all parts, reassemble and reinstall unit.

Note: 50 micron filtration is recommended.

Housing

Spring

Electrical Connection

Piston

(1/2" NPT Conduit)

O-Ring

(FS-925/FS-930)

(FS-926) 1-9/32"

Inlet

Fitting

MAINTENANCE/REPAIR...

Regular maintenance of the total system is recommended to assure sustained optimum performance. These devices are not
field repairable and should be returned to the factory if recalibration or other service is required. After first obtaining a Returned
Goods Authorization (RGA) number, send the unit freight prepaid to the following. Please include a clear description of the
problem plus any application information available.

Dwyer Instruments, Inc.
Attn: Repair Department
102 Highway 212
Michigan City, IN 46360

Important Points!

Product must be maintained and installed in strict accordance with the
National Electrical Code and Dwyer product catalog and instruction
bulletin. Failure to observe this warning could result in serious injuries
or damages.

For hazardous area applications involving such things as (but not
limited to) ignitable mixtures, combustible dust and flammable materials,
use an appropriate explosion-proof enclosure or intrinsically safe
interface device.

The pressure and temperature limitations shown on the individual
catalog pages and drawings for the specified flow switches must not
be exceeded. These pressures and temperatures take into
consideration possible system surge pressures/temperatures and
their frequencies.

Selection of materials for compatibility with the media is critical to the
life and operation of Dwyer products. Take care in the proper selection
of materials of construction, particularly wetted materials.

DWYER INSTRUMENTS,INC.

P .O.BOX 373 MICHIGAN CITY, INDIANA 46361, U.S.A.

Life expectancy of switch contacts varies with applications. Contact
Dwyer if life cycle testing is required.

Ambient temperature changes do affect switch set points, since the
specific gravity of a liquid can vary with temperature.

Dwyer Products have been designed to resist shock and vibration;
however, shock and vibration should be minimized.

Filter liquid media containing particulate and/or debris to ensure the
proper operation of our products.

Electrical entries and mounting points in an enclosed tank may
require liquid/vapor sealing.

Dwyer Products must not be field-repaired.

Physical damage sustained by the product may render it
unserviceable.

Phone: [phone] www.dwyer-inst.com
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