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Puridest Glass Distillation Apparatus
09/2020
Water shortage in mono or bi stage
Float switch mono stage
Float switch bi stage
LAUDA Puridest Glass Distillation Apparatus are protected from overheating in case of low water by two separate safety
devices. Before restarting the unit, a thorough analysis of the malfunction must be carried out by a trained electrician.
After the unit being switched off in case of low water, the water flow through the unit has to be checked, starting from the
cut-off valve of the water mains, through the solenoid valves Y1, Y3 and Y4 (according to model and version) and the
cooling coils of the glass condensers, to the boiler. Furthermore, check the function of float switches S4 and S5 in the rear
part of the water overflow to the right of the boiler. The float switches can be checked by a resistance measurement after
pulling off contact strip X1.
Triggered low water cut-offs of the Distillation Apparatus must be resetted. For this, loosen the black cap nuts at the left-
hand housing wall. Inside the thread a small white plastic pin can be seen that has gently to be pressed inside (e. g. with a
pen) until a clicking sound can be heard. The Glass Distillation Apparatus being switched off during operation is presumably
always due to a defect of the unit. Models PD 2 G and PD 4 G have only one low water cut-off
Pilot lamp "Clean"
Depending on the degree of impurities in the tap and the increasing contamination of the water in the boiler, caused by the
distillation process in the mono stage boiler, a fully automatic rinsing process should be started by pressing key "Clean". The
function "Clean" is also triggered when boiling contaminated water foams up in the boiler and comes into contact with the
electrode in the mono stage boiler.
During the rinsing process, the boiler is filled with water to its upper rim and then drained completely. The contaminated
water flows off through the hose connection marked "contaminated water drain". The boiler is automatically refilled with
water until the heating element is below water level. The distillation process then restarts. The purpose of the function "Clean"
is to exchange contaminated water in the mono stage boiler against clean water.
Caution:
If the separate water supply is installed, the function "Clean" will only work partially as the low conductivity
of the industrial water (e. g. desalinated water) will prevent the water exchange being switched off. In these
cases, the Distillation Apparatus must be switched off (main switch) after the mono stage boiler is filled
with water. The unit must not be switched on again before the boiler has been completely drained through the contami-
nated water drain.