1072_B
7
June 2020
Dryer Performance Testing
The performance of a resin dryer can be checked by measuring the dew point
of its output air.
Connect the 1072A sample tubing to a point on the dryer’s output line, before
the material hopper. Make sure not to exceed the sample tubing temperature
rating.
Turn on the 1072A and allow the reading to stabilize. The initial reading will be
high until all the ambient air is purged from the hygrometer’s tubing and
internal fittings. After a few minutes, the reading should start to drop until a
stable reading is obtained. It can take 30 minutes or more for the unit to
stabilize when first turned on.
NOTE: Not all dryers produce a -40
F dew point. Check with your dryer
manufacturer for expected dew point levels.
Leave the 1072A connected and turned on during material drying and
processing. The built in red light and audible beeper will indicate dryer trouble
within moments of a dew point rise.
A constantly high reading on the 1072A may indicate a malfunctioning dryer or
one that is overloaded by damp material in the hopper. If you suspect that the
1072A is giving an incorrect high reading, perform the Dry-Down Test described
in the Troubleshooting section of this manual.
Material Dryness Testing
The dryness of resin in a hopper can be inferred from the dew point of air
exiting the hopper.
Connect the 1072A sample tubing to a point in the hopper’s air output. Make
Dryer testing
sample location
Material testing
sample location
Dryer
Hopper
Air flow
