Air quality testing is the daily monitoring of the dry air dew point at the dehydrators outlet. Testing is conducted with a LP frost point indicator, MIL-I-24144.

Figure 6-6.A maintenance index page (MIP) for one design and make of high-pressure air compressor systems (page 2 of 2).

DEHYDRATOR DEW POINT READINGS

This reading is taken every 4 hours of dehydrator service. Readings verify that the dehydrator is operating correctly. The normal readings of the various types of air dehydrators are as follows:

1. LP air (type I) dehydrators normal dew point reading is a dew point temperature reading of 40F or lower at 80 lb/in2. This indicates that the dehydrator is delivering an air quality within its design capability. A reading of 50F or higher at 80 lb/in2 indicates that the dehydrator is not working properly, and you should check the applicable technical manual.

2. A dew point temperature reading of -40F or lower at 80 lb/in2 is normal for LP (type II and type III) dehydrators. A reading of -20F or higher at 80 lb/in indicates that the dehydrator is not operating properly, and you should check the applicable technical manual to correct the problem.

3. For HP air dehydrators, a dew point temperature reading of -60F or lower at atmospheric pressure is normal. A reading higher than -60F at atmospheric pressure indicates that the dehydrator is not working properly, and you should check the technical manual for the solution to the problem.