Model 640 & 640CC Instruction Manual
D01206676
Revision A February 2016
32
The mineral oil supplied with the instrument has an open cup flash point of
approximately 188C/370 F.
5.
The magnetic drive should be flushed with clean solvent periodically and
whenever cement spills into the cylinder or particles contaminate the drive. If
cement enters the magnetic drive, it will cause the bearings to wear quickly. If
the worn bearings are not replaced, it may cause the inner magnetic drive shaft
to wear out prematurely. Worn bearings may also cause excessive slurry cup
run-out.
6.
The filter, regulator, lubricator unit (FRL), supplies lubrication and filtration
for the pump air. This unit is attached to the pump air inlet, after the solenoid
valve. The filter unit is upstream of the regulator unit and it should be checked
periodically and the bowl cleaned if filled with water or debris. The lubricator
is located just downstream of the filter. A quality grade of lubricating oil,
approximately SAE 10, should be added routinely to the plastic reservoir,
otherwise it will run dry and leave the air side of the pump un-lubricated,
perhaps leading to premature failure of the pump.
Do not pour the lubricating oil into the filter bowl by mistake.
Potentiometer Mechanism (Pot Mech) Maintenance
12.2
1.
Check upper and lower bearings for smooth, friction free operation. If bearing
operation is not smooth, clean or replace the bearings. If the bearings do not
operate smoothly, it may cause thickening times to increase.
2.
Check for broken wires in the potentiometer resistor. The resistance should
measure between 80 and 100. The surface of the resistor that is in contact with
the wiper may be burnished with a smooth, round rod (such as a screwdriver
blade) to reduce noise in the consistency signal if necessary.
3.
Periodically check that the wiper is making contact with the potentiometer
resistor throughout its entire length of travel.
Slurry Cup Maintenance
12.3
1.
Check the slurry cup after every test to be certain the threads are not
contaminated with cement. Lubricate the threads with grease prior to the start
of every test.
2.
It is recommended that hardened cement slugs be pressed out, rather than
pounded out with a hammer. Pressing tends to cause less damage. When
