The Series PAFS-1000 Averaging Flow Sensorfrom Dwyer Instruments, Inc. isideal for sensing differential pressure in the inlet section of variable air volumeterminal units and fan terminal units. Units can also be used to sense differentialpressure at other locations in the main or branch duct systems.The “H” port senses total pressure and the “L” port senses static pressure. Thedifference between these signals is the differential, or velocity pressure.Models offer up to ten sensing points and lengths of 3-5/32˝ to 23-29/32˝ (8.02 to60.72 cm) to accommodate box sizes of 4˝ to 30˝ (10.16 to 76.20 cm).INSTALLATIONThe Series PAFS-1000 utilizes 1/4˝ ID, 3/8˝ OD tubing. First check that there areno sharp bends in the tubing at any connection. Bends and creases may leak overtime as the tubing ages. Connect the “H” Port to the high input on the differential pressure gage, transmitter,or switch. Connect the “L” Port to the low input on the differential pressure gage, transmitter,or switch.Approximate K factors for models:PAFS-1002: 1.32PAFS-1003: 1.39PAFS-1004: 1.46PAFS-1005: 1.46PAFS-1006: 1.58PAFS-1007: 1.67PAFS-1008: 1.78PAFS-1009: 1.88PAFS-1010: 2.01PAFS-1011: 2.14It may be necessary to calibrate in order to insure an accurate measurement.You can do this by completing a traverse of the duct or fan to determine the deltaP sensed by the PAFS vs. the actual flow.MOUNTING1. Install the unit horizontally to assure accurate velocity readings for units ranging from 3-5/32˝ to 9-29/32˝. If using a unit longer than the PAFS-1005, which is 9-29/32˝, vertical mounting is recommended. 2. Determine the duct’s flow direction and install the Series PAFS-1000 based on the unit’s flow arrow imprint. 3. Cut a 7/8˝ hole in the ducting to accept the unit. 4. Attach using two self-tapping screws inserted in the 3/16˝ mounting holes.Series PAFS-1000 Averaging Flow SensorSpecifications -Installation and Operating InstructionsBulletin PAFS-1000DWYER INSTRUMENTS, INC. Phone: 219/879-8000www.dwyer-inst.comP.O. BOX 373 • MICHIGAN CITY, INDIANA 46360, U.S.A. Fax: 219/872-9057e-mail: info@dwyer-inst.comSPECIFICATIONSService:Air and compatible gases.Wetted Materials:ABS/polycarbonate (UL94-5V). Temperature Limits:Operating: 40 to 120°F (4 to 49°C); Storage: -40 to 140°F (-40 to 60°C).Connection:1/4˝ (6 mm) ID, 3/8˝ (10 mm) OD tubing.Mounting Orientation:Integral flange with gasket.Weight:1 oz (28 g).3-1/2[88.90]1-1/4[31.75]2-3/4[69.85]FOAM GASKET1/8 THK[6.35 THK]APUSH-ONCONNECTIONSFOR 3/8POLY TUBING[9.53 OD]MOUNTING HOLES2XØ3/16 [Ø4.76]7/16[11.11]ModelPAFS-1002PAFS-1003PAFS-1004PAFS-1005PAFS-1006PAFS-1007PAFS-1008PAFS-1009PAFS-1010PAFS-1011Number ofSensing Points12345678910DIMENSIONSSensorLength3-5/32˝ (8.02 cm)5-13/32˝ (13.73 cm)7-21/32˝ (19.55 cm)9-29/32˝ (25.26 cm)12-1/2˝ (31.75 cm)14-3/4˝ (37.47 cm)17-1/8˝ (43.50 cm)19-13/32˝ (49.29 cm)21-21/32˝ (55.01 cm)23-29/32˝ (60.72 cm)©Copyright 2010 Dwyer Instruments, Inc.Printed in U.S.A. 12/13FR# 72-443834-00 Rev.1MOUNTING DETAILSMAINTENANCESensing orifices must be kept free of dust accumulation or debris. Occasionalcleaning may be required.Upon final installation of the Series PAFS-1000 Averaging Flow Sensor, no routinemaintenance is required. A periodic check of system calibration is recommended.The Series PAFS-1000 is not field serviceable and should be returned if repair isneeded (field repair should not be attempted and may void warranty). Be sure toinclude a brief description of the problem plus any relevant application notes.Contact customer service to receive a return goods authorization number beforeshipping.1-3/8˝[35]1-3/8˝[35]7/8˝ [22] DIACLEARANCE HOLE(2) 3/16 DIA HOLE FORSELF TAPPING SCREWSNext >