Velp Scientifica
– UDK139 Operating Manual
10004762/B5
52
8.2.2. Operations to be performed only when necessary
Replacing fuses
Fuses should be re
placed only when necessary, i.e. when the unit doesn’t turn on
and the mains switch does not light up. The fuses must only be replaced by qualified
personnel and only with fuses supplied by Velp Scientifica Srl.
To replace the fuses disconnect the unit from the power supply, unscrew the fuse
caps located on the back of the unit. The unit is fitted with one fuse for each phase:
FUSE diam. 6.3x32 mm, 15 A (250V).
Replacing the protective film on the touch screen
Only replace the protective film if it impairs visibility even after cleaning using a damp
cloth.
Cleaning the condenser
The condenser should be cleaned when it is heavily soiled with salts and organic
matter thus reducing the efficiency of heat exchange.
After switching off the unit:
1.
Unscrew the water tube from the water tap and place the open end in a
receptacle containing water, preferably below the instrument. This triggers
the emptying of the hydraulic circuit and the condenser.
2.
Open the service door of the instrument
3.
Remove the metal clamp that supports the condenser by removing two
screws.
4.
Detatch the black tube from the condenser inlet and outlet and remove it
from the instrument.
5.
Unscrew the screw on the bottom flange of the condenser.
6.
Unscrew the two white bushings on both flanges of the condenser.
7.
Remove the coil. The condenser is now completely dismantled.
8.
Wash the parts under running water or diluted hydrochloric acid to remove
any deposits.
9.
Reassemble the condenser making sure the coil does not touch the walls
of the transparent tube and tighten the bushings and screws.
Cleaning the internal parts of the splash head
To clean the internal parts of the splash head and condenser, proceed as follows:
1.
Fill a test tube with about 25ml of deionized water and 25ml of
concentrated acetic acid and position it in the unit.
2.
Select a method without reagents, with a distillation time of 10 minutes and
without distillation residues removal;
3.
Start analysis.
4.
At the end of analysis empty the test tube by hand.
5.
Carry out 2-3 distilling cycles with approx. 50ml of distilled water in the test-
tube to rinse the internal parts.
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