- 32 -
About frost formation
Operating at 5
℃
, 80
％
RH
→
Approx.
＋
3.5
℃
, Approx.
＋
15
％
RH
Operating at 15
℃
,80
％
RH
→
Approx.
＋
2
℃
, Approx.
＋
13
％
RH
Operating at 25
℃
,80
％
RH
→
Approx.
＋
2
℃
, Approx.
＋
13
％
RH
Operating at 30
℃
,80
％
RH
→
Approx.
＋
1.3
℃
, Approx.
＋
12
％
RH
Operating at 40
℃
,80
％
RH
→
Approx.
＋
1
℃
, Approx.
＋
12
％
RH
3. Defrost operation
The chamber wall, the bottom plate of chamber, and the
packing may have dew condensation depending on the setting
temperature or surrounding environment. However, it gives no
effect on the performance and functional capability of the unit.
The chamber has 2 drain ports at the bottom plate to drain the
condensed water.
To reduce the bottom puddle, tilt the unit just a little back.
Be careful not to tilt too much. The water volume of wick
holder decreased.
While operating the programmed gradient control, the
temperature and humidity control may be little deviated due to
the switching of the refrigeration unit.
The temperature and humidity control may be little deviated
when the ambient temperature is changed.
*
*
Observation window
Cooling fin
Frost
In case that the operation is executed at 30
～
40
℃
or
lower temperature with controlling temperature and
humidity, [Cooling alarm (COL)] or [Temperature/
Humidity control fault] may be activated because of
frost formation on cooling part.
You have a choice of the interval mode (automatic
defrosting) or manual mode (forced defrosting) as defrost
operation.
* Use the operation below 0
℃
for a measure of one-day
low temperature experiment.
(1) Interval defrost operation (Automatic defrosting)
If the interval defrost operation is selected by
[Int.Defrost] key, the defrost operation is executed
every hour automatically when the setting
temperature is 40
℃
or lower.
On account of the hot gas flows into the cooling
coil, the chamber temperature and humidity are
fluctuated for about 10 minutes every hours.
(The fluctuation band depends on the operating
condition.)
Use this mode for the operation beyond 24 hours
with 5
～
15
℃
of set temperature, or more than 1
week with 15
～
25
℃
.
The performance of defrosting is worsened
when selecting interval mode in low ambient
temperature.
*
*
Fluctuation bands of chamber temperature and
humidity while operating with interval defrost
mode are shown as below.
(Room temperature: 20
℃
, measured at the center of
chamber.)
(2) Manual defrost operation (Forced defrosting)
[Cooling alarm (COL)] or [Temperature/ Humidity
control fault] may be activated by forming frost on
cooling part in case of the following conditions.
Check frost formation through the observation
window and execute the forced defrost operation if
needed.
Temperature and humidity is controlled under 30
～
40
℃
or lower setting temperature.
Interval defrost operation is executed when the setting
temperature is at 5
℃
or lower.
Interval defrost operation is executed when the ambient
temperature is low.
In case the ambient humidity is high.
1)
2)
3)
4)
Take out all samples and vessels from the
chamber before forced defrost operation is
started. Sample materials may be damaged by
fluctuation of temperature and time passage.
The frost formation on the cooling coil is dissolved
in water drop by defrost operation and it flows and
be collected into the bottom humidification pan.
However, some water may not be drained through
the overflow port. Turn on [Manual Drain] switch
before the forced defrost operation is started.
