Aalborg AFC - Manual (Page 17)

screen will now become visible. Push the screen out through the inlet fitting. Clean
or replace each of the removed parts as necessary. If alcohol is used for clean-
ing, allow time for drying.
Inspect the flow path inside the transducer for any visible signs of contaminant's.
If necessary, flush the flow path through with alcohol. Thoroughly dry the flow
paths by flowing clean dry gas through.
Carefully re-install the RFE and inlet fitting, avoiding any twisting and deforming
the RFE. Be sure that no dust has collected on the O-ring seal.
NOTE: Over tightening will deform and render the RFE defective.
It is advisable that at least one calibration point be checked after re-installing the
inlet fitting - see section 7.
6.2.3 AFM 36/46 and AFC 36/46 models
Unscrew the four socket head cap screws (two 10-24 and two 6-32) at the inlet
side of the meter. This will release the short square block containing the inlet com-
pression fitting.
The 60 micron filter screen will now become visible. Remove the screen. DO NOT
remove the RFE inside the flow transducer! Clean or replace each of the removed
parts as necessary. If alcohol is used for cleaning, allow time for drying.
Inspect the flow path inside the transducer for any visible signs of contaminant's.
If necessary, flush the flow path through with alcohol. Thoroughly dry the flow
paths by flowing clean dry gas through.
Re-install the inlet parts and filter screen. Be sure that no dust has collected on
the O-ring seal.
It is advisable that at least one calibration point be checked after re-installing the
inlet fitting - see section 7.
6.2.4 Valve Maintenance (AFC)
The solenoid valve consists of 316 and 416 stainless steel, and VITON
7 (or
optional EPR or KALREZ
7) O-rings and seals. No regular maintenance is
required except for periodic cleaning.
Various corrosive gases may demand more frequent replacement of VITON
7 O-
rings and seals inside the valve. Be sure to use an elastomer material, appropri-
ate for your specific gas application. Contact your distributor or Aalborg
7 for
optional sealing materials available.
Set the AFC into PURGE mode, and attempt to flush through with a clean, filtered,
and neutral gas such as nitrogen. [Another option for fully opening the valve is to
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