Retrotec Blower Door - Manual (Page 37)

Page 37 of 87
©Retrotec Inc. 2015
2. If the battery power is too low, connect the DM-2 power cable (usually included in the Umbilical) from the
fan to the gauge. Some fan models do not have this option. If not available, plug the DM-2 power adaptor
into the wall. The DM32 must be powered from an adapter in the wall, or can be plugged into a USB port on
a computer.
4.8 Select the correct Range configuration
All Retrotec fans have multiple Range configurations. The Range configurations are used to affect the airflow and
fan pressure through the fan. During testing, it is necessary to select the correct Range Configuration to achieve
measurable and accurate results.
Each Retrotec DucTester includes three ranges, and each Door Fan comes with 11 Range Configurations for the
greatest possible accuracy and versatility.
Selecting a Range configuration is based upon the air flow that is required to achieve the test pressure in the
enclosure. A general rule of thumb is to select a Range configuration so that the Fan Pressure is twice (or more) the
desired test pressure in the enclosure.
Testing should always be done with the most restrictive Range Configuration on the fan as possible for the following
reasons:
1. Accuracy increases as Fan Pressure increases
2. High Fan Pressure results in high fan speed, which aids in cooling the fan
3. When conducting multi-point tests, starting with a restrictive Range Configuration eliminates the need to
change the Range Configuration during the test.
Note: In European countries where a 50 Hz power system is used, Range Configuration selection becomes more
critical because the fans will run 20% slower. Therefore, there is not as much difference between minimum and
maximum flow on any given Range Configuration.
4.9 Determine which Range to use on a Door Fan
1. Attach Range Ring A and B.
2. Set the gauge to Range Configuration B
3. Adjust the fan speed until the desired Room Pressure is reached.
If using the DM-2 digital gauge:
4. If “TOO LOW” is shown on Channel B of the DM-2, attach the C8 Range Plate. Restrict the flow further, until
the gauge is able to measure a pressure.
5. Press [Range Config] until the correct “Range Config” is displayed on the DM-2 screen.
Or
4. If the desired Room Pressure cannot be reached, take Range Plates or Range Rings off.
5. Press [Range Config] until the correct “Range Config” is displayed on the DM-2 screen.
If using analog gauges:
4. Select a Range Configuration so that the Fan Pressure is twice (or more) the Room Pressure.
4.10 Cannot reach required pressure?