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© Retrotec 2022
Time averaging, seconds
Actual leakage area as measured,
Press [Set Pressure]
Read peak pressure from gauge
Read peak % speed from gauge
Read final % speed from gauge
Set the correct Device on your gauge because it will calculate different results depending on which Device
is selected.
8.6 Check if large fixed errors are caused by pinched tubes
A pinched pressure tube can create a very high reading on the gauge, which is erroneous. In other cases, a
pinched tube will prevent the pressure measurement from reaching the gauge at all. In cases where tubes
get stepped on, they are seldom sealed off completely, but will still cause the gauge readings to jump
around.
Errors in pressure reading from a pinched tube.
It is possible to complete a Blower Door test with a pinched tube. It will appear as if the fan is creating a
pressure in the building, but in fact the results are way off. If the gauge begins to display an unusually high
or unexplained pressure, check the tubing to ensure that it has not been compressed in any way.
• Be careful that no one steps on the tubes, or creates a kink in any of the lines while performing a
test. If this happens, wait a few seconds for the effects to subside before taking any readings from
the gauge.
• Use the metal tube provided with the gauge to pass tubes through tight spaces (such as under
closed doors) to prevent pinching.
8.7 Check if large fixed errors are caused by water in the tube
Water can also cause significant errors if a drop is pulled into the pressure tubes. It is very easy to get a
water drop inside the end of a tube. Simply drag it over a shallow puddle of water, and a drop of water will
get pulled into the tube by capillary action. Notice in the image below how one drop of water in the end of
the tube is creating 190 Pascal pressure. It is possible to complete a Blower Door test with a water drop in
the end of the tube. It will appear as if the fan is creating a pressure in the building, but in fact the results
are way off. Particularly unusual behavior in the gauge could mean that there is water in the end of the
tube.
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