Extension Hoods - Observator Instruments DIFF User Manual

OBSERVATOR
instruments

4. Extension Hoods

There are different types of hoods available for vents larger then the
standard opening of 25x25cm. The cross needs to be mounted
(Velcro) when measuring a diffuser of 40x40 or 60x60cm. The cross
avoids that the measurements are influenced by the vortices created
by the diffuser.
To mount the hood, place the round opening of the hood over the
square opening of the DIFF. The pull strings need to be positioned on
the left
.
Pull the lower pull string and lift the
hood till the lower pull string hooks
behind the sally edge of the DIFF. With
the lower pull string tightened you can
pull the upper pull string.
Note that the upper pull string needs to
be placed above the sally edge.
Span the hood by placing the fiber poles as a cross. The poles can
be placed in the recesses from the edge inside the DIFF. The fiber
poles may bend about ± 6cm while placing them.
There is also a repair kit included to repair holes in the canvas.
Check if the pull strings are fit well around the DIFF and pull them
tight if they are still a bit loose.
V11.2 - EN
DIFF automatic volume flow meter
The AT-242 is required for measuring supply vents in the
housing industry.
The light hood simply slides over the top of the Diff and doesn't
require any additional tightening.
Page 12
User manual
TDC 16-7-2012