R-317 Air Flow Controller

Transcription

1 , Rev. B Product Bulletin R-317 Issue Date February 2016 R-317 Air Flow Controller The R-317 Air Flow Controller is a proportional, direct acting, low volume output signal instrument designed to proportionally control the volume discharge in high velocity mixing units. The R-317 measures the differential between two static pressures and produces an output signal which is proportional to the differential of the static pressures. The R-317 is suitable for control of duct pressures, air flow (as a static pressure high limit), or for use with all makes and types of mixing units in which the volume can be controlled by measuring a pressure differential within the range indicated in Table 1. Specifications Operation The R-317 consists of three chambers divided by two very light diaphragms. A response to pressure differences between the high and low static pressures causes movement of the diaphragms. A seat located in the center of one diaphragm opens or closes the control port. This action varies the output pressure to an actuator directly connected to the dampers which control volume discharge. The R-317 is direct acting only; therefore, an increasing differential pressure increases the output pressure to the actuator while a decreasing differential decreases the output pressure to the actuator. Movement of the diaphragm is opposed by a Fig. 1: R-317 Air Flow Controller light extension spring. This spring is diaphragm is opposed by a light extension spring. This spring is diaphragm is opposed by a light extension spring. This spring is attached to a dial etched with nineteen equal graduations. The set point is varied from one end of the range of pressure differential to the other by one complete revolution of the dial. Note: Never adjust the dial more than 360 in either direction from the factory setting. Installation The R-317 may be mounted inside or outside the mixing unit. The air flow controller is calibrated for vertical mounting and may require recalibration if it is mounted with the diaphragms in the horizontal position. It can be rotated to any of four positions for convenience in piping. Note: It is imperative that the proper pressure sensing tip be used with the R Johnson Controls, Inc. 1 Part No , Rev. B Code No. LIT

2 2 R-317 Product Bulletin Application and Drawing Identification

3 The R-317 features an integral mounting flange and includes a mounting strap and bracket for mounting to ductwork (see Fig. 4). To mount the R-317 using the strap and bracket, proceed as follows: 1. Attach the bracket to the mounting surface. 2. Attach the strap to the controller using the screw provided, through the larger of the two holes in the strap. 3. Slip the strap into offset in the bracket. 4. Use the second screw provided to attach the bracket to the threaded hole in the strap. Calibration Refer to Table 1 for a list of the various models available and their corresponding differential pressure ranges and factory settings. The dot on the face of the dial indicates the factory differential setting for each range. Adjusting Procedure for High Pressure Double Duct Mixing Boxes To adjust the R-317 for high pressure double duct mixing boxes, proceed as follows: 1. Obtain a heating layout (sheet metal plans) upon which the SCFM of each mixing unit is indicated. 2. Obtain a capacity calibration table showing SCFM vs. Flow Controller Pressure for each unit. (This table, if not included with the mixing unit, may be obtained from the unit manufacturer.) 3. From the heating layout, determine the SCFM to be delivered from each mixing unit. 4. Using the calibration table, determine the static pressure drop for the required mixing unit SCFM determined in Step Adjust the R-317 and the unit capacity by turning the dial to the desired setting. This should be all the adjustments required. Special Adjustments If the unit must be checked to determine the actual air delivery or control point of the R-317, obtain a draft gage, tubing, and tee fittings, refer to Fig. 5, and proceed as follows: 1. Attach the tee fittings to the high and low pressure measuring lines. 2. Use the pressure drop indicated on the draft gage and the calibration curve to determine the actual air delivery. 3. If the pressure drop indicated on the gage is above or below the value indicated on the dial, loosen the small set screw on the dial and turn the dial face until it corresponds to the R-317 Product Bulletin 3

4 pressure drop indicated on the gage. Tighten the set screw and turn the adjusting post until the dial indicates the desired pressure difference. Note: Always use a screwdriver to turn the dial adjusting post. Do not remove the dial stop screws. Other Air Systems Connect a draft gage into the measuring line of the R-317 and with the fan running, turn the adjusting dial of the R-317 until it controls at the desired pressure (static, velocity, or total). 4 R-317 Product Bulletin

5 European Single Point of Contact: NA/SA Single Point of Contact: APAC Single Point of Contact: WESTENDHOF ESSEN GERMANY 507 E MICHIGAN ST MILWAUKEE WI USA C/O CONTROLS PRODUCT MANAGEMENT NO. 22 BLOCK D NEW DISTRICT WUXI JIANGSU PROVINCE CHINA Controls Group 507 E. Michigan Street P.O. Box 423 Milwaukee, WI Printed in U.S.A. R-317 Product Bulletin 5