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Oriflow Cobra User Manual

Duct leakage tester
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Cobra
Duct Leakage Tester
User Manual

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Summary of Contents for Oriflow Cobra

  • Page 1 Cobra Duct Leakage Tester User Manual...
  • Page 2 Links to Online Help (QR Code) Video – Duct Leakage Testing Online Technical Library Online Max Leakage Calculator Online Max Leakage Calculator (SMACNA Leakage Class) (% Allowable) Cobra Tester User Manual © Copyright 2021...

  • Page 3: Table Of Contents

    Power Requirements …………………………………..…………….……...….……… Extension Cord Requirements ………………………..…………….……...…………. Flex-Duct Length ………………………………………...…………………….……...…. Determining Maximum Allowable Leakage ….………..……………...…….….……… FREE Oriflow duct test summary form (SMACNA or DW/143) ………….….………. Determining Which Orifice Plate to Use ……………..……………..……..…………. 6 - 7 Duct Leakage Test Setup and Procedure Install Orifice Plate and Upper Tube Section ……………………………..………..….

  • Page 4: Introduction

    Introduction The COBRA duct leakage tester is the most widely used tester in the U.S. It is the simplest to use tester on the market backed by unparalleled customer service and technical support. Call us, find out. The recommended recalibration interval for the plates is 5 years. Note the authority having jurisdiction may override this requirement, and if so, Oriflow has reasonable rates for re- calibrating orifice plates manufactured by Oriflow.

  • Page 5: Prior To Testing

    Do you have an adequate power supply for your tester (see Table 2)? Table 2 – Tester Amp Draw Flow Control Full Load Tester Model Voltage Option Amps Cobra Slide Gate 12.8 Cobra 14.0 Cobra Slide Gate Cobra Cobra Tester User Manual © Copyright 2021...

  • Page 6: Extension Cord Requirements

    If the specification uses SMACNA Leakage Class or Pressure Classification, you will need to calculate the total duct system surface area. Oriflow has a FREE Adobe test summary sheet that will calculate duct surface area, leakage factor, allowable leakage, actual leakage and Pass/Fail criteria. You can find this test summary sheet using the QR code to the right.

  • Page 7: Determining Which Orifice Plate To Use

    ** Minimum based on 0.40 in.wg. across orifice plate. Table 5 – Tester Capacity using the 2-inch Orifice Plate COBRA Tester System Test Minimum Maximum Pressure Leakage** Leakage (in.wg.) (cfm) (cfm) 0.10 ** Minimum based on 0.40 in.wg. across orifice plate. Cobra Tester User Manual © Copyright 2021...
  • Page 8 ** Minimum based on 0.40 in.wg. across orifice plate. Table 7 – Tester Capacity using the 4-inch Orifice Plate COBRA Tester System Test Minimum Maximum Pressure Leakage** Leakage (in.wg.) (cfm) (cfm) 0.10 ** Minimum based on 0.40 in.wg. across orifice plate. Cobra Tester User Manual © Copyright 2021...

  • Page 9: Duct Leakage Test Setup And Procedure

    Refer to Figures 1 through 4. Figure 1 – Install Orifice Plate and then Rotate Clockwise Figure 2 – Rotate Orifice Plate Clockwise until it Locks in Place Cobra Tester User Manual © Copyright 2021...
  • Page 10 After the orifice plate is locked in place, place the upper tube section over the bolt/wing nut set, rotate clockwise, and tighten wing nuts (Figures 3 and 4). Figure 3 – Install Upper Tube Section and Rotate Clockwise Figure 4 – Tighten Wing Nuts after Rotation Cobra Tester User Manual © Copyright 2021...

  • Page 11: Connect Flex-Duct To Orifice Tube

    Using putty or duct tape, seal the connection. See Figure 8. Cobra Tester User Manual © Copyright 2021...
  • Page 12 Connect Flex-Duct and Static Pressure Tap to Duct System (continued) Figure 6 – Flex-duct Connection to Duct System Figure 7 – Connection to Duct System using Static Pressure Tap Cobra Tester User Manual © Copyright 2021...

  • Page 13: Duct Leakage Test Setup (Supply)

    See Figure 8 for the test setup for SUPPLY duct system testing (positive pressure testing). On the backside of the DUCT SYSTEM pressure gauge, move the pressure tubing to the pressure port labeled SUPPLY SYSTEM. Figure 8 – Duct Leakage Test Setup for a SUPPLY System Cobra Tester User Manual © Copyright 2021...

  • Page 14: Duct Leakage Test Setup (Return/Exhaust)

    You will determine the leakage of the system since the air drawn from the blower is discharged through the orifice plate. Figure 9 – Duct Leakage Test Setup for a RETURN/EXHAUST System Cobra Tester User Manual © Copyright 2021...

  • Page 15: Zeroing Pressure Gauges

    6. Press MENU button two times to get back to the pressure reading. 7. Pressure should be reading zero or within +/- 0.02 in.wg. If not, repeat steps. Cobra Tester User Manual © Copyright 2021...

  • Page 16: Avoiding Over-Pressurization

    The faster you rotate the knob, the more quickly the speed will increase. See Figures 12. Figure 12 – Obtaining System Test Pressure (inlet slide model on left, VFD speed control model on right) Cobra Tester User Manual © Copyright 2021...

  • Page 17: Obtaining System Test Pressure

    Always refer to the calibration certificate(s) that came with your calibrated orifice plate(s). Figure 14 – Orifice Plate Pressure Drop (analog on left, digital on right) Cobra Tester User Manual © Copyright 2021...
  • Page 18 (for this example, the constant is "134.42"). The exact leakage is 134.42 x (square root of 2.46) = 210.8 cfm. Better yet, download Oriflow’s test summary sheet described on the bottom of page 5 of this manual.

  • Page 19: Troubleshooting

    Open duct end that was supposed to be sealed/capped-off for the leak test. A non-toxic smoke machine is an excellent tool for locating significant sources of leakage. Call ORIFLOW at 727-400-4881 or to our website at www.oriflow.com for more information.

  • Page 20: Can't Obtain System Test Pressure (Duct Pressure Too High)

    Use the next larger sized orifice. GFI/GFCI trips This happens when using a Cobra duct leakage tester with the variable speed option. The supply wiring has ground wired to neutral which causes the GFI to activate when the tester is operating.

  • Page 21: Zero Or Very Small Reading On Orifice Plate Gauge

    If you feel a lot of air coming out of the tube end, you should see a pressure reading on the gauge ORIFICE PLATE. Cobra Tester User Manual © Copyright 2021...

  • Page 22: Duct System Gauge (Digital) Displays Ufl Or Ofl

    UFL/OFL displays when TESTER is ON (airflow through orifice tube) Are you using another blower in series with the tester? The digital gauges used on the Cobra tester can read up to about 11 in.wg. maximum. Cobra Tester User Manual...
  • Page 23 ORIFLOW LLC 2125 Range Rd., Suite B Clearwater, Florida 33765 Customer Service: 727-400-4881 Technical Support: 727-466-4435 sales@oriflow.com engineering@oriflow.com Cobra Tester User Manual © Copyright 2021...

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