Sanyo MDF-793AT, MDF-593AT instruction manual Back-up system, Rough scheme

OPERATING INSTRUCTIONS

Back-up system

WARNING

As with any equipment that uses CO2 gas, there is a likelihood of oxygen depletion in the vicinity of the equipment. It is important that you assess the work site to endure there is suitable and sufficient ventilation. If restricted ventilation is suspected, then other methods of ensuring a safe environment must be considered. These may include atmosphere monitoring and warning devices.

The freezer AT type is provided with an automatic liquid CO2 gas injection device as a back-up system. This freezer prevents the chamber temperature from going up by injecting the liquid CO2 gas when the power supply is disconnected (power failure, disconnection of power cord, breaker OFF) or in the case of failure of freezer itself. The liquid CO2 gas is injected with the activation of solenoid valve energized by battery when the chamber temperature reaches the alarm temperature.

Following shows the procedure for setting the back-up system.

1.Setting of liquid CO2 gas cylinder

By using the joint and pipe enclosed with the freezer, connect the liquid CO2 gas cylinder to the joint of the back-up system. For this setting, consult with a qualified gas supplier or Sanyo sales agency.

2.After setting the liquid CO2 gas cylinder, operate the freezer until the chamber temperature reaches the required level.

3.Set the warning indicator of the recorder at the temperature higher than -70oC. The back-up system is operated continuously if the warning indicator is set at the temperature lower than -70oC. This means the liquid CO2 gas is consumed very quickly.

Rough scheme	Liquid CO2
	gas cylinder
Solenoid valve	Pipe

4.Switch on the back-up system.

5.Make sure that liquid CO2 gas spouts into the freezer chamber by pressing the CO2 back-up test switch.

Note:

•The liquid CO2 gas cylinder loses its cooling capacity at speed when the ambient temperature is over 31oC. Install the liquid CO2 gas cylinder in the cool environment. And the duration of back-up time per one liquid CO2 gas cylinder varies depending on the ambient temperature. Refer to “Installation of back-up system” enclosed with the freezer for the available back-up time.

•The liquid CO2 gas cylinder should be a siphon type.

•Use the pipe enclosed with the freezer for the setting. (The extension of the pipe is not permitted

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