Waters Prep Series Installation And Maintenance Manual page 127

a. Insert a jeweler's screwdriver into the hole.
Adjusting the transducer
b. Turn the screwdriver slowly clockwise until the pressure display
value reaches 0.
c. Turn the screwdriver slowly counterclockwise until a small positive
number appears.
Solvent proportioning valve pair test
This test lets you evaluate the system when you suspect a defective
proportioning valve is causing erratic chromatographic results.
Always observe safe laboratory practices when handling
Warning:
solvents.
You can perform the test in less than 1 hour. Use pure methanol as the mobile
phase with a UV-absorbing sample.
The sample is used to "spike" one reservoir of methanol, and must be linear in
absorbance throughout the test range.
Preparing solvent
To prepare the solvent:
1. Fill reservoirs A and B with solvent 1 (100% methanol).
Performance tests 3-43