Instructions

8 Using the product
22
7
Start measurement: Press the [▼] (Start) key.
-
Once the measuring range 0 to
20,000 microns / 0 to 26.66 mbar is
reached, the current vacuum value is
shown on the instrument display.
The instrument also displays the
current ambient temperature, the
water evaporation temperature which
corresponds to the vacuum reading,
and the delta between these two
temperatures.
8
End measurement: Press the
[▼] (Stop)
key.
-
The measurement result is displayed.
Press the [▲] New key to reset the determined values. If necessary, a
test can also be started again.
9
Press [Menu/Enter] to return to the main menu.
8.2.3 Pressure Leak Test
The temperature compensated leakage test can be used to check the leak
tightness of systems. For this purpose both the system pressure and the
ambient temperature are measured over a defined period of time.
To this end, a temperature probe that measures the ambient
temperature or a Smart Probe for measuring the air temperature can be
connected. As a result, information is provided about the temperature-
compensated differential pressure and about the temperature at the
beginning/end of the test. Due to the temperature compensation, the
actual pressure drop is displayed as delta P. If no temperature probe is
connected, you may also perform the tightness test without temperature
compensation.
Surface temperature probes (e.g. testo 115i) can also be used for the
temperature-compensated leakage testing, but must not be used to
measure surface temperature. They must be positioned as far as
possible to measure the air temperature. If a surface probe is used, in
the Settings menu of the testo 550s / testo 557s, the Auto Tfac
(Temperature compensation factor) must be switched off, see
section 8.3.4.