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Thermo Scientific
Maintenance and Servicing
Section 7
For top performance and efficiency, the MP-12A Water Still should be
kept clean and free of scale. The MP-12A has a built-in deionization
system to pretreat the boiler feed water and eliminate scale build-up. It is
recommended that the boiler be drained and refilled with fresh water daily
to flush the boiler of the concentration of contaminants from the previous
day's run.
Warning To avoid electrical shock, always disconnect from power supply
before maintenance and servicing. Refer servicing to qualified personnel.
For continued protection against possible fire hazard, replace fuses only
with the same type and rating of fuse.
Warning Wear eye and hand protection when using acid for cleaning, as
acid spattering may occur.
If cleaning is desired after extended operation or boiler scale is visible due
to bypassing the deionizer system, the unit should be cleaned with a
hydrochloric acid solution. This is accomplished as follows:
1. Push unit "OFF" switch.
2. Disconnect the product outlet tube J from the product cooler G at
Point 4 (see Figure 7). Connect 4' length of 3/8" I.D. vinyl tubing
from parts box to product cooler at Point 4. Route vinyl tubing to
drain.
3. Drain boiler 2/3 by opening stopcock V. Close stopcock V after boiler
has drained.
4. Use the spare pinch clamp from the parts box to shut off overflow tube
from constant level chamber B as close as possible to overflow stem.
5. Carefully pour approximately 800 ml of 10% hydrochloric acid
solution into top of constant level chamber B. You may need to add
water to the boiler to bring solution level up to scale level.
(continued)
s
s
12A Water Still
7-1
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