9
4. PERFORMING AIRFLOW MEASUREMENT FOR RA3.9.4.1.2(4) STEP 4
1. Make sure whole house fan(s) are off and note the speed being tested on each if there are multiple
2. Setup and install WHF-PFH on first fan to be tested if there are multiple fans and select appropriate
ring
a. If flow channel is reading “LOW” after you zero out with “open” Ring. Refer to blower door fan
manufacturer instructions to install Ring “A”
3. On both TEC and Retrotec fans, connect pressure tap from flow hood to channel A (pressure channel)
input tap on digital gauge
4. On both TEC and Retrotec fans, leave the channel A (pressure channel) reference tap open to read
pressure inside the dwelling
5. On TEC Model 3 fan, connect the pressure tap from the blower door fan to the channel B (flow
channel) input tap
6. On Retrotec fans, connect the pressure tap from the blower door fan to the channel B (flow channel)
reference tap
7. On TEC Model 3 fan, leave the channel B (flow channel) reference tap open to reference inside the
dwelling
8. On Retrotec fans, leave the channel B (flow channel) input tap open to read pressure inside the
dwelling
9. It is suggested to turn on blower door fan prior to whole house fan to pressurize the flow hood
slightly
10. Turn on whole house fan(s) and adjust blower door fan accordingly to “zero out” the pressure in the
flow hood
11. Document your airflow reading
