Hold-Off Time; Temperature Digression - Fisher Scientific Isotemp Plus 13-986-120 Instruction Manual

O
PERATION
Caution
INCREASING the offset value
DECREASES the temperature at
which the system controls. If the offset
is inadvertently set too high, the
chamber temperature can fall below
zero and cause evaporator freeze-up.
10
For Example:
The display indicates 4°C but a reference thermometer in
the refrigerator chamber indicates 6°C. The operator
holds in the Menu KEY and changes the display value
from 0.0 to 2.0. The Menu key is pressed two additional
times so that the controller again displays chamber tem-
perature. Now the display indicates a chamber tempera-
ture of 6°C and the controller begins to cool to the desired
temperature of 4°C.
Allow an additional 30 to 40 minutes for the refrigerator to
again stabilize. If the display is still inaccurate, repeat the
calibration offset procedure.
Hold Off Time
Following the offset menu is the hold-off (Ho) menu. The
display will momentarily flash "Ho", followed by a number.
The number shown is the delay time in minutes between
compressor activations. Use the UP/DOWN keypads to
change the value.
Increasing the hold-off time will allow additional time for
the evaporator to defrost. This can reduce the chance of
evaporator freeze-up during times of high humidity.
Pressing the Menu keypad while in the Ho mode, enters
the hold-off time displayed, and returns controller opera-
tion to the temperature display mode.

Temperature Digression

By pressing the Increase keypad, the display will show
the warmest temperature recorded since the unit was
energized or the digression values were reset. Pressing
the Decrease keypad will display the coldest temperature
recorded since the unit was energized or the digression
values were reset.
To reset the temperature digression values, simply press
the Increase and Decrease keypads at the same time.
The display will show Clr, indicating the controller will
begin recording new warm and cold digressions once
more.