Changing The Time Averaging Period; Using The Baseline Pressure Feature; Example: Measuring Building Depressurization From An Exhaust Fan - TEC DG-700 Operating Instructions Manual

2.4 Changing the Time Averaging Period

The DG-700 has a choice of 4 time averaging periods which are applied to both pressure measurement
channels. The default time averaging period is 1 second average. To change the selected time averaging
period, press the TIME AVG button. The selected time averaging period is shown in the TIME AVG
portion of the gauge display. (See Section 1.5 for an overview of the time averaging feature).

2.5 Using the Baseline Pressure Feature


2.5.a Example: Measuring Building Depressurization from an Exhaust Fan
A common building performance application requiring use of a baseline pressure reading is determining the extent of
building depressurization caused by turning on an exhaust fan. In order to accurately quantify the building
depressurization, the user first needs to know the building pressure (with reference to outside) prior to the exhaust
fan being turned on. This initial pressure reading, known as the baseline building pressure, can be quickly measured
and then used to adjust the final building pressure reading (after the exhaust fan is turned on) to determine the actual
change in building pressure caused by fan operation.
- Set up Channel A to measure building pressure with reference to outside (e.g. run tubing from the Channel A
Reference tap to outside and leave the Channel A Input tap open to the building – assumes the gauge is in the
building).
- With the exhaust fan off, turn on the gauge and leave it in the PR/PR mode.
- Press the BASELINE button. The word "BASELINE" will
begin to flash in the Channel A display, indicating that the
baseline feature has been initiated. At this point, the gauge is
monitoring the real-time Channel A baseline pressure
reading, but is not recording the reading. The Channel B
display is not active at this time.
- Press the START button to begin the baseline measurement
procedure on Channel A. Once the START button is
pressed, the word "BASELINE" stops flashing and the
gauge begins recording a long term average baseline
pressure reading on Channel A. During the baseline
measurement procedure, the Channel B display is used as a
timer to let the user know how long (in seconds) the baseline measurement has been active. The longer the
measurement time, generally the more stable the baseline reading typically becomes. In the screen to the right,
the measured baseline pressure is –2.6 Pascals (measured over the past 45 seconds).
- Once you are satisfied with the baseline pressure reading,
press the ENTER key to accept and enter the baseline
pressure reading into the gauge. After pressing ENTER,
Channel A will now display the baseline adjusted pressure
reading (i.e. the measured baseline pressure reading will be
The Baseline feature on Channel A allows the user to measure and record a
baseline pressure reading, and then display the baseline adjusted pressure reading.
(See Section 1.6 for an overview of the baseline pressure feature)
9
Chapter 2 Pressure/Pressure Mode
Operating Instructions
for the DG700