Techne DB-3A - Manual (Page 21)

D B - 3 a n d D B - 3 A O P E R A T O R ’ S M A N U A L
P A G E 19
Setting the Overtemperature Cut-out
DB-3
In the event of a fault occurring which could cause the heater to remain
on, power is removed from the heater when the block temperature
reaches approximately 110°C.
DB-3A
An adjustable overtemperature cut-out is fitted to these units. As
supplied it is set to remove power from the heater should the block
temperature exceed approximately 210°C. If you need to prevent the
block temperature exceeding a lower value, the overtemperature cut-
out may be re-adjusted downwards. Note that the cut-out should be set
to trip at least 5°C above the maximum desired operating temperature.
To set the overtemperature cut-out, turn the reset button (located on the
back panel of the unit) fully clockwise then:
either:
• Heat the block to the desired cut-out temperature and turn the reset
button anti-clockwise until the unit just cuts out.
or:
• Heat the block to the required maximum operating temperature and
turn the reset button anti-clockwise until the unit just cuts out. Now
turn the reset button an additional small amount clockwise.
When the cut-out operates, the unit stops working and the
overtemperature cut-out indicator lights.
Remove the block from the unit by screwing the extractor tool into the
thermometer hole and lifting the block vertically. Remember that high
temperatures are dangerous; wear insulating gloves and take extreme
care. Wait for the temperature to fall, perhaps by as much as 40°C, and
press the reset button. The unit will now work as usual.