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vwr.com I Instruction manual VWR® U Water System
5.4.9 Cleaning the PE Tank
Warning!
NaOH is a strong corrosion agent which may harm the body. Be careful to protect yourself
when cleaning the tank
.
a)
Switch the system to Standby mode when the tank is full (100%).
b)
Prepare 0.1 M NaOH using analytical grade NaOH (120 g NaOH for the 30-L tank, and 240
g for the 60-L tank). Dissolve in 1 L pure water, and then pour into the water tank. Gently
mix.
c)
Soak the tank overnight.
d)
Take out the 8 mm PE tubing and connect it to the drain outlet of the tank, put the other end
into the drain.
Note: Please check local regulations on how to properly discharge 0.1 M NaOH.
e)
Open the drain valve underneath the tank, drain all solution.
f)
Close the valve by turning it 90º. Put system into Ready mode to fill the tank full. Put system
into Standby mode.
g)
Gently tilt the tank and swirl, then open the valve to drain all water.
h)
Repeat Step f and g for two more time.
i)
Take a water sample from the tank. Use a pH paper to check its pH. If the water is basic,
repeat
Step f
and
g
one more time.
j)
Plug the tubing back to the system. Put the system into Ready mode.
