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4.2 Adjusting the Duct System
and Air Devices
In order to prevent the fans from consuming more power
than necessary, it is important to keep the pressure drop in
the system as low as possible.
It is also important that ducting systems and air devices are
correctly adjusted to provide the comfort expected.
When adjusting air devices and the duct system installed
in combination with the GOLD, it is appropriate to follow
the proportionality method.
This means that the proportion between the airflows in
branch ducts stays constant even if the airflow in the main
ducts is changed. The same proportion applies to the air
devices in the installation.
When adjusting the ducting system there is provision for
locking the speed of the fans in the unit to a specific pre-
set flow rate, see Section 6.5.
4.2.1 Adjustment Sequence
The system should be adjusted in the following order:
1. Adjust of the air devices in each branch duct.
2. Adjust the branch ducts.
3. Adjust the main ducts.
4.2.2 Adjustment Procedure
1. Set all the air devices and dampers to the fully open
position.
2. Calculate the ratio of the airflow reading to the design
airflow of all the air devices, branch ducts and main ducts.
The air device in every branch that has the lowest ratio
should be fully open. Use this air device as an INDEX AIR
DEVICE. The same applies to branch dampers and main
dampers.
Example on how to carry out adjustments
– Start adjusting duct branch B, since this one has
the highest ratio.
– The last air device, B3, has the lowest ratio and
should be fully open.
Adjust the other air devices, B1 and B2, so that
these will have the same ratio as air device B3 (see
item 5 above).
– Now adjust the air devices in branch duct C. Air
device C4 should be fully open; throttle the others
to the same ratio.
– Adjust the air devices in branch duct A. The index
air device here is air device A3, which means that
you first throttle air device A4 (the reference device)
to device A3:s ratio.
Thereafter the others are adjusted to the same ratio
as air device A4.
– Throttle branch damper B to the same ratio as branch damper A,
throttle branch damper C to the same ratio as branch damper A.
Check that all dampers have the same ratio.
When the adjustment has been completed, 3 air devices and
one branch damper should stand fully open to obtain the lowest
possible pressure in the system.
We reserve the right to alter specifications without notice.
When you've completed the adjustments, one air device in
every branch, one branch damper and one main damper
should consequently be fully open.
3. Start adjusting the main duct that has the highest ratio
and the branch duct in the main duct that has the highest
ratio. Starting from this point enables you to "press" the
air in front of you toward the sections of the system that
have the least air.
4. Adjust the last air device on the duct branch so that
it will have the same ratio as the index device. This air
device will serve as the REFERENCE AIR DEVICE. Often
it is the last air device on the branch that has the lowest
ratio and should be open. In this case, the same air device
serves as the index device and reference device.
5. Throttle the other air devices in the branch to the same
ratio as the reference device.
Note! The ratio in the reference device will change every
time another air device is throttled, so in practice the ratio
for the reference device can be set slightly higher. The
reference device must be measured in between each air
device throttled.
6. Go to the branch that had the next highest ratio and
adjust the air devices there, etc.
Note! All branch dampers should be fully open until all air
devices have been adjusted.
7. Throttle the branch damper that had the highest ratio
to the same ratio that the branch of the lowest ratio had.
Note! Keep in mind that the index damper changes ratio;
proceed as described in item 5.
8. When all branches have been adjusted, throttle the
main dampers in the same manner.
Also see the example below on how to carry out adjust-
ments.
GB.GOLDLP.170830
q
= design airflow (l/s)
p
q
= airflow reading (l/s)
m
q
m
K (Ratio) =
q
p
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