When the tests have been completed the instrument should be cleaned as follows:

1. Close the Whitey valve and open the burette cock, allowing the caustic solution to drain into the level bottle. Discard the caustic solution if it has become weak or, if still good, store in a sealed glass container for future use.
2. Open the Whitey valve, fill the level bottle with warm water and raise the level bottle above the top of the burette. Fill the burette with the water until it overflows at the caustic trap.
3. Lower the level bottle and allow the burette to drain through the Whitey valve and back into the level bottle. Repeat step #2 several times or until all traces of caustic solution have been drained from the burette and fittings.
4. Remove the pressure gauge from the gauge adapter (5039), rinse in warm water and dry.
5. Remove the dial thermometer, rinse off the stem and dry. Apply a small amount of "O" ring lubricant to the stem and install the thermometer in the tester. Move the thermometer up and down several times to lubricate the internal "O" ring of the tester.

Note: Caustic solution will eventually discolor the Teflon plastic connection tubing (5052) and also cause deterioration of the rubber coupling (5046). If this condition occurs, the parts should be replaced.

Calibration of the Pressure Gauge/Dial Thermometer:

The pressure gauge and thermometer should be tested for accuracy at the beginning of each shift. Procedures for recalibration are sent with the instrument and are available upon request from Zahm & Nagel CO.