Signal Menu, 4-Pa-Test - Wohler DC 100PRO Bedienungsanleitung

3. Signal menu, 4-Pa-test

Wöhler DC 100
PRO
3. Signal menu, 4-Pa-test
When the device is switched ON it conducts a self-test. Afterwards the time
and date are output. When the device's logger mode has been activated,
the text "Log" followed by the current measured and stored values appears
instead of the self-test – the device then switches back OFF. (In this case the
logger function has to be deactivated first.) For as long as a flashing cursor
points to the subprogram P=0 and the display shows the text "Stab. time"
(stabilisation time), no hose should be attached and no differential pressure
applied: during this phase the device is determining its zero point.
Figure 3.1: Selecting the Signal menu; cursor
at signal
3.1 4-Pa-Test
If you use an indoor air-dependent combustion installation and an exhaust-
gas system in a closed air loop at the same time, a potentially dangerous va-
cuum may be the result. The Wöhler DC 100 permits to check this 4 Pa va-
PRO
cuum limit and to print out the chronological trend for a (adjustable) period of
5 minutes as a chart. Two capillary tubes are used to register the differential
pressure between heating equipment room and outdoor air. Two equally long,
flexible capillary tubes are used to register the differential pressure between
heating equipment room and reference site which is pneumatically (hydrau-
lically) disconnected from the combustion-air system (outdoor air, staircase).
The differential pressure is then measured by a pressure sensor. The capillary
tubes can either be routed to the staircase leading outward, through the win-
dow gasket, or through the door frame and/or the keyhole. The second ca-
pillary tube remains unshortened in the heating equipment room. Particularly
on stormy days the staircase is an excellent and stable reference site. The
differential pressure values may not exceed 4 Pa if the combustion installation
is operated with maximum suction capacity.
The capillary tubes may only be connected to the ports of the DC 100 after
PRO
switching on and zeroing the device. It is recommended to couple the out-
door and/or reference-site connection with the negative terminal and to
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