Retrotec FanTestic (ATTMA) - Manual (Page 39)

rev-2014-10-27
Page 39 of 58
©Retrotec Inc. 2011-2014
When to change range during a test
If fan pressure (or flow values) are too low to be in the valid calibrated region of the fan for the induced
pressure point being measured, the digits will turn red at the row/column of the fan pressure line
affected. This would indicate the need for a range change to increase the fan pressure being used. A
rule of thumb to use is that fan pressure readings should be at least twice the required induced
pressure.
a) If TOO LOW appears on the gauge:

Increase fan pressure (restrict the flow) by installing a smaller flow range (ex. start at C8, put in
two more plugs for C6).

Make sure this flow range change is recorded in your notes/test form.
b) If the fan is close to 100% fan speed without achieving the target pressure:

Decrease fan pressure (increase the flow) by installing a larger flow range (ex. start at C8,
remove C range plate for B).

Make sure this flow range change is recorded in your notes/test form.
5.12 Baseline/bias pressure, final [Pa]
This is the bias pressure after a pressurization or depressurization test.
According to the ATTMA standard, at least 10 bias pressure readings (taken with measurements
averaged over 10 seconds) are required after the induced pressures are measured, with the fan turned
off.
Values can be measured and entered manually by using the [Baseline] function on the Retrotec gauge,
or let the automatic test capture them.
FanTestic calculates the average final baseline and reports it in the Data set. Initial and final baseline
values are averaged and used to correct the building gauge pressure readings.
P02 = average of all post-test Baseline pressures
P02- = average of negative post-test Baseline pressures
P02+ = average of positive post-test Baseline pressures
Note that P02- can be zero if there are no negative Baseline pressures in your data.
5.13 Temperature, final