How to Use a Digital Manometer to Check Gas Pressure on a Propane/Natural Water Heater

The Digital Manometer is also called a differential pressure meter. It is used to measure gas supply and draft pressure in residential or light commercial properties. Extech, Testo and UEi are top manufacturers of manometers. The accuracy of these meters is greatly debated but most companies gurantee them. The following list provides an overview of pressure measurement steps. Each step is discussed in subsequent paragraphs. Note that the first 4 steps should only be performed the first time the meter is used and each time the transducer is changed.

Instructions

Difficulty: Moderately Challenging

Things You’ll Need:

• Digital Meter
• Data Acquisition Kit
• Meter-to-PC Interface Cable
• Batteries

1. Select a Transducer model that covers the desired range.
2. Plug the Transducer into the meter's input jack
   Connecting the Transducer to the Meter
   1. Press the POWER button to turn the meter OFF.
   2. Remove the existing transducer, if necessary, by unplugging it from the meter’s input jack (top of meter).
   3. Plug the new transducer into the meter’s input jack.
3. Program the Transducer Range
   Selecting Transducer Range
   1. With the meter turned OFF, simultaneously press and hold the HOLD, SENSOR, & RECORD buttons down.
   2. While holding the three buttons down, press the POWER key momentarily. Release
   the 3 buttons when the LCD display switches on.
   3. A number will appear on the LCD that represents the Transducer type. Select the Transducer type by pressing the SENSOR TYPE key until the desired transducer number appears. Select the transducer from the list below in step 5.
   4. Press the ZERO button to store the new transducer type. The meter will memorize the new type even when the meter is turned OFF.
   5. Select the transducer from the following list:
   • Select 2 for the 30 psi (2 bars) transducer
   • Select 5 for the 75 psi (5 bars) transducer
   • Select 10 for the 150 psi (10 bars) transducer
   • Select 20 for the 300 psi (20 bars) transducer
   NOTE: The meter does not need to be recalibrated each time the transducer is changed.
4. Select the measurement units.
   Selecting the Unit of Measure
   Press the UNIT key to select the desired unit of measure: Bar, psi, Kg/cm2, mmHg, inHg, mH2O, inch H2O, or Atmospheres (ATP).
5. Zero the meter.
   Push-button Zero
   1. Attach a transducer to the meter, turn the meter ON, and select the range that matches the attached transducer as described in the 'Preparation for Use' section.
   2. With the transducer attached to the meter (but not attached to the process) press the ZERO button. Note that the ZERO button should always be pressed after swapping transducers.
   3. If the display reads zero after pressing the ZERO button proceed to the next section. If the display does not zero, the transducer may be defective.
6. Connect the Transducer to the process under test.
   Connect Transducer Port to Process
   1. Ensure that the process under test is not pressurized
   2. Connect the Transducer's ¼” PS, 19 teeth per inch threaded port to the process under test.
   3. Apply pressure to the process.
   4. Read the pressure on the meter's LCD.
7. Apply pressure to the process under test
8. Read pressure reading on the meter's LCD
   Data Hold
   1. When a reading is on the display that you wish to hold, press the Data Hold button.
   2. The reading will freeze and the HOLD icon will appear on the display.
   3. Press the Data Hold button again to release the reading and return the meter to normal operation.
   Minimum/Maximum Reading Memory
   1. Press the RECORD/RECALL button to start tracking the highest (MAX) and lowest(MIN) readings. The REC indicator will appear on the LCD.
   2. Take pressure measurements.
   3. When pressure measurements are complete, press the RECORD/RECALL button to recall the Maximum reading recorded (the MAX indicator will appear on the LCD).
   4. Press the RECORD/RECALL button again to recall the Minimum reading recorded (the MIN indicator will appear on the LCD).
   5. To exit this mode and return the meter to normal operation, press and hold the RECORD/RECALL button until the REC indicator goes out.

Tips & Warnings

• Specified accuracy applies to meter at 23oC
• Re-calibration is not required each time a new transducer is attached.