Dynalab 4000-0000 - Manuel (Page 5)

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CARE AND MAINTENANCE
N.B. Before commencing any maintenance, cleaning or
fault finding the equipment should be isolated
from the mains electricity supply. These
operations should be only carried out by suitably
qualified personnel.
Only spare parts supplied or approved by Bibby Sterilin Ltd.,
or its agent should be used. Fitting of non-approved parts
may affect the performance or safety of the equipment.
CLEANING
Over a period of operation scale deposits will build up inside
the boiler. To obtain optimum performance from the still,
the scale should be removed on a regular basis.
The time span between cleaning depends greatly on the
hardness of the water supply and the amount of use.
Frequently used stills in hard water areas may need
descaling once a week whereas in a soft water area several
weeks may elapse before descaling is necessary.
N.B. Heavy scaling will reduce distilled water quality
and can shorten the life of the heating element.
It is possible to descale the Merit Water Still without
dismantling the glassware by following these instructions in
conjunction with Control of Substances Hazardous to Health
regulations (COSHH) 1988.
1. Switch off the electricity supply to the still and allow it
to cool completely.
2. Turn off the cooling water supply.
3. Open the stopcock on the constant level control and
allow the boiler to drain completely, Close stopcock.
4. Turn on the cooling water supply and allow the boiler
to fill to approximately half way to its normal operating
level. Turn off the water supply.
5. Into the open funnel of the constant level control
carefully add about 1 litre of 10% formic acid solution
or kettle descaler.
Do not use strong acids such as hydrochloric, this can
cause severe corrosion of the metal heating element.
WARNING!
ALWAYS HANDLE ACIDS WITH GREAT CARE.
PROTECTIVE CLOTHING, GLOVES AND FACE-
MASKS SHOULD BE WORN DURING THE
DESCALING OPERATION.
REMOVE ANY ACID SPILLS IMMEDIATELY.
Turn on the water supply and fill the boiler to the
normal operating level. The water will flush the acid
into the boiler. The water supply should be turned off
when the level in the boiler is slightly below the
overflow.
6. Leave the acid in the boiler to desolve the scale. This
may take some time depending on the severity of the
build-up.
7. Open the stopcock and allow the boiler to drain.
Note: If the acid in the boiler has not been
completely neutralised the liquid flowing to drain
may be highly acidic. All necessary safety
precautions should be observed around the drain
and any effluent control procedures followed.
8. Close the stopcock, turn on the water and allow the
boiler to fill with cold water. Turn off the water, re-
open the stopcock and allow the boiler to drain.
Repeat this procedure three times.
9. The Merit Water Still may now be restarted by referring
to the instructions given under “Operation” in this
manual.
Note: The stand and outer surfaces of the glassware
should be cleaned using a damp cloth and a mild
detergent solution.
LIST OF SPARE PARTS
The following components are available from most
laboratory suppliers. In case of difficulty, please contact
Bibby Sterilin Ltd.
Catalogue No.
Boiler W4000/B
Condenser WC48/M2
Heater
(complete with thermostats) 240V
A6/6
(complete with thermostats) 220V A6/6/EURO
Set of heater fixings W4000/GK
(flange, gasket, insert and bolts)
Hose kit W4000/HK
CIRCUIT DIAGRAM
L N
Lamp
(S)
Thermostat
Element
(S)
Switch
(W4000/EURO only)
(S)
Thermostat
E
Heater flange
(S) Denotes safety critical component.