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 during the off-cycle. 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 operation to the temperature display mode.
Error Codes
Error codes indicate when the controller is sensing a
problem. A description of each is given below. See the
Troubleshooting Table for additional information on error
codes.
E1
Open sensor.
E2
Under temperature. Temperature at sensor is
less than –36°C.
E3
Over temperature. Temperature at sensor is
greater than 37°C.
Fluorescent Lamps
The interior lamp is controlled by a rocker switch on the
header panel. This light may be operated any time the
cabinet power is turned on at the keyed power switch. If
the interior lamp fails, replace with the same size and
wattage lamp. DO NOT USE REDUCED WATTAGE
LAMPS. The reduced wattage lamps generally fail to
light below 60°F (15°C).
11
O
PERATION
Caution
INCREASING the offset value
DECREASES the temperature at
which the system controls. If the off-
set is inadvertently set too high, the
chamber’s control temperature can fall
below zero and cause evaporator
freeze-up. This is caused by the
evaporator temperature not rising
above 0°C and not defrosting during
the compressor “off cycle”.
Note
While in any of the controller mode
setups (temp set, calibration offset
or units), the controller will wait 15
seconds for a new value to be
entered. If there is no keypad oper-
ation within the 15-second time win-
dow, control will automatically revert
to the temperature display mode and
the Mode LED will turn off.
