Amphenol Kaye CTR-40, Руководство пользователя, Страница: 43 / 84

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7 General Operation
7.6
minutes for the temperature to settle and stabilize. There may be a small over-
shoot or undershoot of about 0.5°C during this process.
Refrigeration
Cooling is provided by a compact refrigeration system utilizing the ozone safe
R-410A HFC refrigerant. Refrigeration is often not needed when the bath is
above 45 to 60°C. The automated system automatically turns the system off
when above 60°C. The refrigeration system automatically changes modes de-
pending upon bath temperature and operation needs as described below. The re-
frigeration system is activated when the switch on the front panel is turned on.
If the bath is below the 60°C cutoff point and is set to a temperature above
60°C, the refrigeration shuts off to protect it from overheating and creating ex-
cessive internal pressures. If the bath is above 60°C and is set to a new temper-
ature below the cutoff temperature, the refrigeration turns on again at 59°C.
When the bath is controlling at temperatures between the 60°C and 0°C, the
bath operates in a low cooling capacity mode with the hot gas bypass valve on
(HGb on). The HGb system reduces the cooling capacity and helps to improve
the bath stability within that temperature range. Since more cooling capacity is
generally required below 0°C, the hot gas bypass is turned off (HGb off) pro-
viding more cooling capacity.
When the bath is cooled from temperatures below the cutoff point to 0°C and if
the new set-point is at least 2°C below the current bath temperature, the cooling
turns to maximum capacity (HGb off) until the bath is within about 0.5°C of
the new set-point. This provides the fastest cooling possible to achieve the new
set-point temperature. As indicated, the cooling is always maximum below
0°C.
When heating the bath from temperatures of –40°C and the new set-point is at
least 10°C above the current bath temperature, the refrigeration turns off until
the bath is about 1°C below the new set-point. This permits the maximum heat-
ing rate to reach the higher temperatures as quickly as possible. The cooling re-
mains off at temperatures above 60°C.
The automatic cooling mode may not be ideal for all circumstances. The auto-
matic mode may be turned off permitting manual control. These controls are
available through the front panel as described in Section 8.13, Operating Pa-
rameters, or through the digital interface as described in Sections 9.2, Interface
Commands and 9.3, Cooling Control. The cooling mode control may be set to
automatic, on, or off. With these selections the refrigeration is either in auto-
matic as described above, always on, or always off. The hot gas bypass modes
are similarly selectable between automatic, on, or off. This system is either in
automatic as described above, always on (low cooling capacity) or always off
(high cooling capacity).