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Measuring depressurization caused by exhaust devices, air handlers and door closures is not  something new in the field of building science. The Energy Conservatory has had a procedure in  its blower door manual for over 20 years. There are many recommended procedures and  protocols out there, but they all require documenting changes in pressure. If you want to  diagnose solutions to depressurization issues, you’ll want to document incremental pressure  changes as each additional exhaust appliance is turned on, as well as document the effects of  the air handler and door closures. 

Using the TEC WiFi Link with the iTEC-700 iOS or Android app has made this documentation  easier. You can leave the DG-700 in the Combustion Appliance Zone (CAZ) and view the changes  in pressure caused by turning on exhaust devices on a phone or tablet via a WiFi connection.  

To document these changes, use iTEC-700 to change the readings to a 10-second average, and  then take a screenshot of the results at each step. 

If you already have a computer in the field, an even better way to document pressure changes  at each step is to use our free TECLOG3 software. TECLOG3 can display and record real-time  CAZ-to-outside and water heater vent pressures. You can easily add and label event markers in  the software or create periods of record that will calculate long-term averages of these  pressure changes. 

Using the TEC WiFi Link for Data Logging Pressures 

The TEC WiFi Link as a stand-alone data logger 

There are many possible applications where measuring pressures over time would help you  diagnose pressure-related issues in a home or business. Here’s a short list of a few of the many  possible applications: 

  1. Frequency of use of exhaust devises or air handlers 
  2. How often are multiple exhaust devises on at the same time 
  3. Building pressure changes caused by exhaust devises 
  4. Pressure in CAZ and chimney vent 
  5. Pressures between two zones, such as an office space and a warehouse storing  chemicals 
  6. Pressure changes when exhaust devices and ventilation systems are used in those two  zones 

Our TECLOG3 software has been available for years to support these applications, but it  required leaving a computer on-site to gather the data. 

The WiFi Link accessory for the DG-700 has memory that will allow you to leave just the DG-700  with a WiFi Link attached to gather the data. The sampling interval can be adjusted to allow you  to record samples over extended lengths of time. Some examples are: 

  1. Data points at 1 second interval for 8 daysgauge 
  2. Data points at 5 second interval for 40 days 
  3. Data points at 60 second interval for 485 days 

You get the idea. The length of time the gauge batteries will power a stand-alone data logging  session depends on the power level of the batteries installed, and the auto-zero interval – the  longer the auto zero interval, the longer the batteries will last. A fresh set of alkaline batteries  and an auto-zero interval of 60 seconds will provide approximately 8 days of power for data  

logging. It’s also possible to power both the gauge and WiFi link with a wall power adapter and  a custom Y-connector available from TEC. 

Putting the WiFi Link in data-logging mode 

You will need to use the iTEC for PC software to launch the WiFi Link to data-logging mode and  to retrieve the data. This software is a free download from our website and can be found here

Analyzing the data 

The data retrieved from the WiFi Link can be viewed in our TECLOG3 graphing software or  loaded into an Excel spreadsheet.