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Chart Environmental Chambers 
 
Operation 
2.  Control Power (OFF, ON) 
This switch controls the 24vdc control power in the control system.  If this switch is 
turned OFF, all control functions will be disabled.  The temperature controllers are 
powered from a 115vac circuit, so they will remain powered up even if the control 
power switch is turned OFF, however no heating, cooling, etc will be able to take 
place. 
3.  Chamber Reset (push button) 
This button will be illuminated under normal operation.  If the Temperature Safety 
controller goes into a high or low temperature alarm, this button will no longer be 
illuminated.  The respective heating or cooling action will not be enabled until the 
alarm condition is no longer present and the Chamber Reset button has been pressed. 
4.  Air Safety (up, down; touch pad) 
This controller is located inside the control box and is not to be adjusted by the 
operator.  The controller has pre-set alarm set points to protect the chamber from 
thermal run-away and extreme temperature conditions.   
5.  SERIAL COMM (communications connection) 
This connector is provided on the back of the control box for future serial 
communications with the Watlow controller.  The cable that is attached to this 
connector is coiled up inside the control panel
 
CAUTION:  If the chamber is left with the circulation fan running, and either no 
temperature set point, or no liquid nitrogen supply, the internal chamber 
temperature will rise.  This rise in temperature could damage product inside 
the chamber if it is not controlled. 
 
The following graph shows the rise in internal chamber temperature with the circulation 
fan running and no cooling output being applied.  It is important to note that the 
circulation fan does generate a small amount of heat, which causes the internal chamber 
temperature to rise slightly from ambient to about 28°C.  This data assumes the chamber 
started at ambient temperature, there was no live heat generating product in the chamber, 
and neither heat nor cool outputs are being applied. 
                                                 
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 If the RS-232 option is ordered, the cable will be installed to the controller. 
 
 
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