22
11. If a thermometer is to be used, it may be fitted in the end of the top cover of the thermoregulator between
the two lugs, using the O-ring supplied with the unit. If a bridge piece is fitted, it is necessary to remove the
bung (
5
) to insert the thermometer through the plate into the bath.
12. Fill the bath to between the minimum and maximum levels stated in the specification. If water is used,
demineralised water is preferred to reduce the formation of scale. Ultra-pure deionised or RO water with a
resistivity of > 1 Mohm should not be used, as this can leach the iron from the stainless steel and lead to
corrosion. If necessary, add a little tap water to the pure water in the bath. If scale should form, use only mild
de-scaling agents to remove it. DO NOT attempt to hammer, chip or scrape the deposits from the surface of
the bath.
13. Recommended liquids:
Temperature
Liquid
-40°C to 0°C
40% water, 40% ethylene glycol and 20% alcohol
-20°C to 30°C
50% water and 50% ethylene glycol
5°C to 95°C
Water, preferably de-ionised with neutral pH
10°C to 150°C
Dow Corning Silicone Oil 200 series*
10°C to 250°C
Dow Corning Silicone Oil 210H/100cs series*
*Warning: check gel life at top end of range.
Extraction may be necessary at high temperatures; always check the manufacturer’s data and safety sheets
before using any of the liquids.
In all cases the OVER-TEMPERATURE CUT-OUT must be set correctly for the liquid being used and the
temperature at which it is to operate
14. A bath that is fitted with a lid or insulating ball blanket gives the best operating conditions. A lid or ball
blanket will prevent vapour loss, heat loss and give better temperature control. See the section on accessories
for further information on available lids. If an open bath is used above 80°C (i.e. where steam or other readily
condensing vapours are present) the operation of the unit, particularly the digital display, may be affected.
Below about 80°C a cover becomes less important but will still give better temperature control.
15. The symbols next to the indicator lamps on the front panel of the thermoregulators have the following
meanings:
: the power indicator
: the heater indicator
: the over-temperature indicator
Lugs
O-ring
Thermometer
Bridge
