Checkline PT-DPM - Manual (Page 13)

13
T T roubleshooting roubleshooting
When the surface temperature probe is not on a
surface, Air Temperature and Surface Temperature
appear to be different:
Under normal conditions with the surface probe in air
T
a and T s should be within the combined tolerance
of each sensor (typically 1°C). It is possible for the
difference to be larger if the surface probe has
recently been in contact with surfaces that are at a
different temperature than air.
RH value is slow to stabilize:
If the probe is exposed to a very low humidity for an
extended time period and then placed in a high
humidity environment the displayed Relative
Humidity (RH) may appear to respond slowly. Allow
the probe to stabilize 30 minutes for a change of RH
greater than 50%. It may take longer if the probe
was left at low RH for several months. To increase
response time soak the sensor in a damp face cloth
overnight to recondition the RH sensor.
Surface Temperature reads much higher than expected:
The probe tip may be dirty or damaged. Clean the
probe tip by soaking in water or solvent. If Ts contin-
ues to read high then return the probe for service.
Surface temperature value does not agree with expect-
ed surface temperature or surface temperature probe is
slow to respond:
In some cases the surface being measured is very
rough and a good thermal connection from the probe
tip to the surface is not possible. If possible place a
small drop of water on the surface and then place
the probe tip into the water drop. Extremely quick
and accurate results can be obtained in this manner.