Retrotec DM-2 Operation Manual
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Retrotec DM-2 Operation Manual

Pressure gauges
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Operation Manual
rev-2013-12-02
Pressure Gauges
DM-2
Retrotec Inc.

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Summary of Contents for Retrotec DM-2

  • Page 1 Operation Manual rev-2013-12-02 Pressure Gauges DM-2 Retrotec Inc.

  • Page 2: Table Of Contents

    The information in this document is subject to change without notice. Retrotec reserves the right to make revisions to this publication without obligation to notify any person or entity of any such changes.
  • Page 3 To change the Power Down Hour........................23 3.1.8 Surface Area Unit ..........................24 To change the Area units ........................... 24 3.1.9 Building Volume Unit ..........................24 To change the Volume units ..........................24 3.1.10 European, Separator ......................... 24 Page 3 of 72 ©Retrotec Inc. 2012...
  • Page 4 8.1.2 Control connections ..........................41 To connect the gauge to a Retrotec fan or variable speed fan drive ..............41 To connect the gauge to a Minneapolis Model 3 or Model 4 Fan ................ 42 Control a fan with the gauge to measure pressure and flow ..........42 To conduct a basic pressure test and ensure your gauge is working ..............
  • Page 5 If the Serial Number and Calibration Date are not valid ............ 53 9.12 If the keys on the DM-2 Keypad are not working .............. 53 To fix the keypad if the keypad cable has come loose and keys are not working ..........53 9.13...

  • Page 6: Digital Gauge Basics

    The connections panel on the back of the gauge is where all external devices are connected to the DM-2. The display provides information on the current test mode and/or setup, as well as the device status and measurement values. The keypad is where the user inputs data to the DM-2, and operates the DM-2 functions.

  • Page 7: The Dm-2 Screen

    1,200 metres (4,000 feet) between the gauge and the fan. 1.1.2 The DM-2 Screen The Display Screen is where all measurement values are shown, as well as the current status of the device, and test configuration. Table 1: DM-2 Gauge Screen Page for Description more...

  • Page 8: The Keypad

    1.2 Batteries The DM-2 can draw power from an AC power supply through a 2000 or 3000 fan, directly from the charger plugged into a wall outlet, or from four AA batteries.

  • Page 9: Charging Batteries

    The DM-2 includes the ability to recharge the batteries inside the gauge. The batteries will not start charging if the DM-2 is not turned on first (i.e. you must turn on the DM-2 first, and then plug in the AC power supply to charge the batteries).

  • Page 10: To Select Proper Battery Type

    1.3 Resetting the Gauge If the DM-2 ever becomes frozen, or stops responding, it can be reset. Depending on the age of the gauge, there are two ways to reset a gauge. To reset a DM-2 with the Reset button 1.

  • Page 11: To Reset A Dm-2 Without Using The Reset Button

    4. Re-install the batteries. 1.4 Screen Contrast Older model DM-2 gauges include the ability to change the screen contrast in order to improve visibility in different light conditions. Newer models have the voltage to the screen regulated so the contrast adjustment is not necessary.

  • Page 12: Keypad Functions

    The DM-2 is equipped with a backlight to improve visibility. The backlight turns on for a brief time when any key is pressed. When the DM-2 is on, pressing [On/Off] briefly will turn the backlight on permanently. Pressing it quickly again will turn the backlight off.

  • Page 13: Mode

    Mode, see Section 3.3 Mode Setup. Table 2 lists all the Modes, the possible units that can be set on the DM-2, and what the results mean (note that some results and units are not available on all gauge models).

  • Page 14: Setup

    To establish a baseline pressure 1. Press [Baseline] to begin acquiring the baseline or bias pressure. The gauge displays “acquiring” and begins to sample the baseline pressure. While acquiring the pressure value, Page 14 of 72 ©Retrotec Inc. 2012...

  • Page 15: Time Avg

    The longer the gauge is turned on, the larger this error can become. With Auto Zero on, the gauge will automatically zero the gauge every 8 seconds. In general, the DM-2 should be used with auto zero feature on. However, the function does consume extra battery power.

  • Page 16: Set Speed

    To use the Set Speed function 1. Press [Set Speed] to activate the automatic control. 2. Input the desired speed using the DM-2 keypad. Speed is input as a percentage, and can be any value from 1-100. 3. Press [Enter] to start the fan. The fan will accelerate until the desired speed is achieved.

  • Page 17: In Set Speed

     The screen will display either "- - - - ", "Jog" or "Hold" (when in Set Speed or Set Pressure mode).  When not in Set Speed or Set Pressure mode, the DM-2 will not enter Jog mode (but Hold mode can be activated at any time).

  • Page 18: In Set Pressure Mode

    Press [Set Pressure] [75] and now pressing the [@ Pressure] key will cycle between; “CFM”, “CFM @50Pa”, and “CFM @75Pa”. [@ Pressure] When numerical input is required, the key functions to input the decimal point Page 18 of 72 ©Retrotec Inc. 2012...

  • Page 19: Set The Gauge Up With Only The Devices And Results You Use Regularly

    [Device] key scrolls through Mode Setup Access the Mode Setup sub-menu to choose which Results are available to display on “Channel B Result”, and to choose the units for the results being displayed Page 19 of 72 ©Retrotec Inc. 2012...

  • Page 20: Full Screen Timeout

    [Enter] key. 3.1.1 Full Screen Timeout Some DM-2 gauges, (firmware Version 3.0 or higher), have a large format screen which automatically appears when no key press is recorded for a period of time. The length of time that must pass is determined by the Full Screen Timeout setting.

  • Page 21: Language

    The current firmware and hardware versions, and the date of last calibration information can be found in the [Setup] Menu. To view version information 1. Press [Setup] to access the Setup Menu. 2. Press [] or [] to select "Display Version Info" in the list. Page 21 of 72 ©Retrotec Inc. 2012...

  • Page 22: N Setting For Estimating Flow @ Pressure During House And Duct Leakage Test

    For example: If we guess at the n value of a duct as being 0.6 and measure 100 CFM at 20 Pa (by accident or by design), then the DM-2 will complete the following calculation to estimate the flow at 25 ��������@20 ����...

  • Page 23: To Change The N Value

    3.1.7 Power Down Hour The Power Down Hour helps to maximize battery power by enabling the DM-2 to automatically turn off when it has been inactive for a set time period. The feature can be set to any value between 0 and 255 hours.

  • Page 24: Surface Area Unit

    European conventions use a comma (,) rather than a decimal point (.) to separate the integer portion of a number from the fractional portion. The gauge supports both conventions. Select 'yes' to represent the decimal as a comma, choose 'no' to use a period. Page 24 of 72 ©Retrotec Inc. 2012...

  • Page 25: To Change The European Separator Units

    3. Press [] or [] to select “2.5”, “3.0”, or “3.5”. 3.2 Device Setup The gauge supports fan equipment from Retrotec and virtually every calibrated fan manufacturer on the market. Table 5: List of compatible devices that can be used with the DM-2...
  • Page 26 Your gauge may be set up differently by a Vendor of yourself. Model 200 Fan 600 Fan 900 Fan 1000 Fan 2000 Fan 3000 Fan Mn Duct Blaster B Mn Model 3/4 Fan Page 26 of 72 ©Retrotec Inc. 2012...

  • Page 27: Enable And Disable Devices

    It is also possible to enable and disable Range Configurations for each of the Devices being used. This will eliminate the need to scroll through each Range when pressing [Range Config] when it can be Page 27 of 72 ©Retrotec Inc. 2012...

  • Page 28: To Enable/Disable Flow Range Configurations In Device [Setup]

    Disabled Range Configurations can always be enabled if necessary. Table 6: DM-2 compatible devices and associated Flow Range configurations Calibrated Fan...

  • Page 29: To Configure Modes

    4. Some modes have an associated “@ Pressure”. To change it, press [] or [] to highlight the associated "@ Pressure", and press [Enter]. Input the new value using the number keys on the keypad, and press [Enter] again. Page 29 of 72 ©Retrotec Inc. 2012...

  • Page 30: Understand The Pressure Gauge

    One inch of water column (in WC) = 249 Pa = 5.2 psf To measure a pressure 5. Connect a pressure tube to the blue port of the DM-2. 6. Press [On]. 7. Place the end of the tube into a glass of water, slightly more than 1 inch below the surface.

  • Page 31: Measure A Negative Pressure

    Figure 4: The gauge displaying a negative pressure (-251.5 Pa). 4.3 Analog Magnehelic Gauges Retrotec no longer manufactures or sells analog gauges. It is recommended that Blower Door systems using analog gauges be upgraded with a digital gauge. Retrotec manufactured three types of analog gauges: ...

  • Page 32: Retrotec's Magnehelic Gauge System (Right)

    Note that it's important to zero the analog gauge by tapping the front panel before use, as readings will be incorrect if the gauge does not read zero before any tubes are attached. Figure 5: Digital and analog gauges display a pressure of 50.2 Pa. (RetrotecDigital DM-2 left); Retrotec’s magnehelic gauge system (right).

  • Page 33: Reduce Bias Pressures, Static Or Fluctuating

    A T works well too. Combining these methods gives a list you can go by if Baseline pressures are above 2 Pa or you simply want to increase repeatability. Your outdoor pressure pickup tube should: Page 33 of 72 ©Retrotec Inc. 2012...
  • Page 34 After that, time averaging or long Baseline recordings will reduce the impact of these wind pressures. Detailed instructions for dealing with fluctuating wind can be found in Troubleshooting Error! eference source not found.. Page 34 of 72 ©Retrotec Inc. 2012...

  • Page 35: Reduce Uncertainty In Results By Taking Lots Of Readings

    1.5 Pa 1.5 Pa 10 s 8.6% 10 s 1.5 Pa 10 s 7.9% 10 s 1.5 Pa 100 s 6.5% 20 s 0.5 Pa 100 s 5.9% Page 35 of 72 ©Retrotec Inc. 2012...

  • Page 36: Check Your Gauge To See If It Needs To Be Sent To Factory For Re-Calibration

    Disconnect the Blue and connect the Green from the Green port to the Red Port to check that tube and the negative versus positive calibration of the gauge. Figure 6: Yellow tube between Channel A & B. Blue tube check of positive ports. Green from negative to positive ports. Page 36 of 72 ©Retrotec Inc. 2012...

  • Page 37: To Perform A Cross Port Check

    The same procedure can be followed to compare two gauges. Connect the tube between corresponding ports on two gauges as shown in Figure 8. The reading on both gauges should be the same. Page 37 of 72 ©Retrotec Inc. 2012...

  • Page 38: To Perform A T-Connection Fan Pressure Check

    A similar procedure can be performed, by using a syringe to create a Fan Pressure. This can be done with either one or multiple gauges. Although the procedure with a syringe is fairly widely used, it is not recommended by Retrotec for the following reasons: ...
  • Page 39 Figure 10: Syringe check setup Page 39 of 72 ©Retrotec Inc. 2012...

  • Page 40: Use The Gauge With A Calibrated Fan For Air Leakage Testing

    8.1.1 Pressure port connections Retrotec has a specially designed connection port that makes a perfect seal and grips the tube well, but releases without tearing the tubing after multiple uses. This exclusive connector was designed by Retrotec to make contact with the both tube internally and externally with a shallow taper.

  • Page 41: Control Connections

     USB PC – The USB (Universal Serial Bus) port is used to connect the gauge to a computer equipped with Retrotec’s FanTestic software to run tests automatically. The computer can assume complete control of the gauge for data acquisition and control of advanced automated testing.

  • Page 42: To Connect The Gauge To A Minneapolis Model 3 Or Model 4 Fan

    If available, the green pressure tube should be attached to the green bulkhead fitting labeled “B (+)” on the fan. 5. Attach the Umbilical power cord to the port labeled “12V DC” or “DM-2 Power” on the Fan Top, if the gauge requires recharging.

  • Page 43: Measure Air Handler Flow Using Hole Flow On The Gauge

    8.3 Measure Air Handler flow using Hole Flow on the gauge The Retrotec gauge can be used to measure the amount of air flowing through a hole. This feature enables the gauge to be used as an Exhaust Fan Flow Meter, by simply cutting a couple of holes in a cardboard box.
  • Page 44 Box pressures below 3 Pa are less accurate because small fluctuations in pressure will affect the flow a lot. Try the same fan with different holes to see the different results. Page 44 of 72 ©Retrotec Inc. 2012...

  • Page 45: Troubleshooting

    A moving tube can cause a significant error. For instance, a tube that is attached both to the gauge and Page 45 of 72 ©Retrotec Inc. 2012...

  • Page 46: To See The Effect Of A Moving Tube

    This does not solve the problem completely, but it does make it easier to take a reading. Page 46 of 72 ©Retrotec Inc. 2012...

  • Page 47: Use Time Averaging Feature To Reduce The Effects Of Wind

    A wind damping system can be used to average out the wind, and get a more stable pressure reading. In addition to a number of suggestions for obtaining better performance from a single tube system, Page 47 of 72 ©Retrotec Inc. 2012...

  • Page 48: No Cost Wind Damping Procedure

    Retrotec offers two wind-damping kits specifically designed to reduce the pressure fluctuations due to wind. The basic wind-damping kit consists of a dual-tube pressure averaging system and will work in wind conditions up to about 10 mph. The deluxe wind-damping kit (our “Wild Wind Tamer”) consists of a four-tube engineered damping system that will provide damping results in winds up to 20 mph.

  • Page 49: To Learn How Time Averaging Can Cause Error

    190 Pascal pressure. It is possible to complete a Blower Door test with a water drop in the end of the tube. It will appear as if the fan is creating a pressure in the building, but Page 49 of 72 ©Retrotec Inc. 2012...

  • Page 50: Check If Large Fixed Errors Are Caused By Sun Heating The Tubes

    To determine correct flow if Range selected was different than the actual Range used: 1. Select the Fan Pressure reading for which a corrected flow value is needed. 2. Find this Fan Pressure value in the left column of the flow conversion tables in Appendix Page 50 of 72 ©Retrotec Inc. 2012...

  • Page 51: Fans Without Reference Tube Have Results Adjusted By Gauge

    For example, set Device to 1000, range to C1, time averaging to 10 seconds. Set the leakage area on an enclosure by adjusting the size of the hole. When using the Retrotec simulator, use the sliding panels to adjust the size of the hole. Optionally, measure the leakage area with a Door Fan using EqLA10 which you can access using the Mode key.

  • Page 52: Keep The Keep Rechargeable Batteries In Top Shape

    The DM-2 is designed to recharge NiMH batteries in the gauge, eliminating the need to purchase a stand-alone battery charger. The charging cycle is designed to fully discharge batteries before recharging them. This can cause problems if the DM-2 is connected to a power plug for only brief periods of time.

  • Page 53: If The Serial Number And Calibration Date Are Not Valid

    9.12 If the keys on the DM-2 Keypad are not working If the DM-2 will power on, but one or more keys do not work, the cables may have come dislodged. To rectify the cable problem, follow these steps:...

  • Page 54: Updating Firmware

    9.13 Updating Firmware The latest firmware is Version 3.01b. The gauge must be returned to Retrotec to have the firmware updated. 9.13.1 Firmware Changes Table 10: Firmware changes from versions prior to 2.29 to the current version 3.01b.
  • Page 55 0.5-1.00 Info 0.5-1.00 Power Down 0-255 Hour Surface Area Unit sq ft, m Building Volume cu ft, m Unit European , Yes (,) /No (.) Separator Sig Figs 3.5, 3.0, 2.5 Large Display Page 55 of 72 ©Retrotec Inc. 2012...

  • Page 56: Appendix A: The Gauge Calculates Flow Based On Pressure Readings From The Fan

    Fan Pressure across the inlet. “PrB” will thus show a pressure difference that is larger than the actual fan pressure, larger by an amount equal to the induced room pressure being measured on Channel A. Page 56 of 72 ©Retrotec Inc. 2012...

  • Page 57: To Determine The Flow For A Particular Fan Pressure Fp

    “PrB” is left as the raw measured value and does not have the Channel A value already subtracted. If using a raw measured value read from “PrB” on a Retrotec gauge, use the following equation to adjust the Fan Pressure and calculate the flow: ��...
  • Page 58 3 Holes 0.5000 44.6000 0.000 2 Holes 0.5000 28.0000 0.000 1 Hole 0.5000 10.8300 0.000 0.5000 43.7300 0.000 Exhaust 0.5000 20.7200 0.000 0.5000 10.0700 0.000 Mn True 0.5000 115.0000 0.000 Flow 0.5000 154.0000 0.000 Page 58 of 72 ©Retrotec Inc. 2012...
  • Page 59 0.4700 51.5800 0.000 0.0000 1.0530 800 / 900 0.4670 30.4200 0.000 0.0000 1.0480 0.4420 27.7100 0.000 0.0000 1.0230 0.4830 17.2600 0.000 0.0000 1.0310 0.4740 12.7100 0.000 0.0000 0.9850 0.5100 5.7700 0.000 0.0000 1.0570 Page 59 of 72 ©Retrotec Inc. 2012...

  • Page 60: Appendix B: Manually Calculate Flow If Required Test Pressure Cannot Be Reached

    The factors depend on the “n” value chosen, and Table 13 is for “n” of 0.65 which is typical for houses. Table 13: Factors for when a building pressure of 50 Pa cannot be reached (“n” value of 0.65) Pressure Cannot reach Pressure Cannot reach achieved 50 factor achieved 50 factor Page 60 of 72 ©Retrotec Inc. 2012...

  • Page 61: Cannot Reach 25 Pa Factors

    Thus the estimated result for CFM at 25 Pa will be 708 CFM. The factors depend on the value chosen, and Table 13 is for of 0.6 which is typical for duct systems. Page 61 of 72 ©Retrotec Inc. 2012...
  • Page 62 Table 14: Factors for when a building pressure of 25 Pa cannot be reached (n value of 0.6) Pressure Cannot reach achieved 25 factor 1.00 1.02 1.05 1.08 1.11 1.14 1.18 1.22 1.26 1.31 1.36 1.42 1.48 1.55 1.64 1.73 1.85 1.98 2.15 2.35 2.63 Page 62 of 72 ©Retrotec Inc. 2012...

  • Page 63: Appendix C: Errors Occur In Estimated Flow If Gauge And Actual "N" Don't Match

    6.2% 12.8% 19.8% -8.8% -4.5% 0.0% 4.7% 9.6% 14.7% -6.7% -3.4% 0.0% 3.5% 7.2% 11.0% -5.0% -2.5% 0.0% 2.6% 5.2% 8.0% -3.5% -1.8% 0.0% 1.8% 3.6% 5.5% -2.2% -1.1% 0.0% 1.1% 2.3% 3.4% Page 63 of 72 ©Retrotec Inc. 2012...
  • Page 64 10 to 50 Pa, and determining the slope of the line: Flow = C �� ×���������������� The graph of pressure versus flow will be linear if graphed on a log-log scale, and the slope will be n. Page 64 of 72 ©Retrotec Inc. 2012...

  • Page 65: Appendix D: Adjust Flow Values For Temperature Difference

    Multiply the flow you measured by the factor to get the air flow corrected for temperature difference. Retrotec’s FanTestic software automatically corrects flow values for any temperature difference when inside and outside temperatures are entered into the software.
  • Page 66 0.970 0.979 0.988 0.998 1.007 1.016 0.938 0.947 0.956 0.965 0.975 0.984 0.993 1.002 1.011 0.934 0.943 0.952 0.961 0.970 0.980 0.989 0.998 1.007 0.930 0.939 0.948 0.957 0.966 0.975 0.984 0.993 1.003 Page 66 of 72 ©Retrotec Inc. 2012...

  • Page 67: Appendix E: Tables To Correct Flow If Range Selected Did Not Match Installed Range

    Here is where to find those tables depending on the type of system you are using: For Blower Doors see: Door Fan Operation Manual, Appendix D: Flow Conversion Tables http://retrotec.com/Portals/5/Documents/Manuals/Manual-Door%20Fan%20Operation.pdf For DucTesters see: DucTester Operation & Testing Manual, Appendix C: Flow Tables http://retrotec.com/Downloads/WebsitePDFs/Manual-DucTester%20Operation%20&%20Testing.pdf Page 67 of 72 ©Retrotec Inc. 2012...
  • Page 68 Watch this quick video on choosing the wrong range and how to recognize it: Video (image): http://www.youtube.com/watch?v=JP1RsL3pm8E&list=UUr- qgIDfAh9wq88Pye4vE8w&index=48&feature=plpp_video Page 68 of 72 ©Retrotec Inc. 2012...

  • Page 69: Appendix F: Setting Up For A Test With Alaska's Akwarm Software

    27. Press [] or [] to set to “3.5” 28. Press [Exit] to exit the “Setup” menu and save these Setup choices. Your gauge is now set up for performing an Air Leakage Test with Alaska’s AKWarm Software. Page 69 of 72 ©Retrotec Inc. 2012...

  • Page 70: Glossary

    Glossary Term Definition Air Current Tester Neutrally buoyant smoke (manufactured by Retrotec Inc.) used to locate leakage locations, and to observe the direction of air flow, or to see if pressure neutralization between two zones is reached. air leakage Pertains to how leaky an enclosure may be; The movement/flow of air through the building Envelope, which is driven by either or both positive (infiltration) or negative (exfiltration) pressure differences or test pressures across the building Envelope.
  • Page 71 The Open Range, the Range Plate or Range Ring that is used on the fan during a Door Fan test. See Retrotec’s Range Configuration QuickGuide Range Plate The Range attachment on the Retrotec Door, which holds Ranges C8, C6, C4, C3, C2, C1, L4, L2, and L1. See Retrotec’s Range Configuration QuickGuide. Range Ring The plastic Range attachments on the Retrotec Door, which include Range A and Range B.
  • Page 72 Averaging can be block averages that will update for the length of the average or rolling (moving) averages that will update continuously by displaying the average over the past time period. Page 72 of 72 ©Retrotec Inc. 2012...

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