Troubleshooting 5-1
November 2005
Problems and
Recommended Solutions
Problem: The loop current is outside the range of 4-20 mA, as
shown on display or current meter. In some cases, 22 mA
can be ordered as the fault current.
Solution: The process dewpoint is out of range. If the dewpoint is
above +10°C (+50°F), the current will go to 22 mA.
Apply dry air for 20 minutes. If the dewpoint doesn't
decrease, consult the factory.
If the dewpoint is below -90°C (-130°F), the current will
go below 4 mA and then to 22 mA as fault current.
Expose the DewPro to ambient air for several minutes. If
the error remains, the cause may be a defective sensor
assembly or an electronics malfunction. Consult the
factory.
Problem: There is no current.
Solution: Check the voltage and polarity across +/- terminals with a
DC voltmeter. If the voltage is within 12-28 VDC,
consult the factory.
Problem: The response time is very slow.
Solution: Verify the flow with an air flowmeter. If the orifice is at
the outlet of a 7 to 8 bar (=100 psig) process pressure, the
air flow should indicate 20 to 30 1/h (500 cc/min., 1 cfh).
If the flow is dramatically lower, the inlet filter may be
clogged. Remove the 2 micron filter and clean it with a
solvent or replace it.
Removing the Filter Figure 5-1 below shows a breakdown of filter parts for removal.
Figure 5-1: Filter Parts
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