Thermo Electron 8600 Series, Руководство по устранению неисправностей

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General Operation
1.1 Initial Start Up
1. Power Switch on.
2. Cabinet temperature 0.5°C or warmer than set point.
3. Fans 1 and 2 turn ON.
4. High stage compressor turns ON, after ten seconds delay.
5. Low stage compressor turns ON when:
A. Thirty seconds after high stage starts and heat exchanger probe reads
–41°C or colder or
B. Five minutes after high stage starts and heat exchanger probe reads
between –33°C to –40°C.
If heat exchanger probe warms-up to –20°C or warmer, the low stage
compressor shuts down until either condition 5A or 5B is met. After thirty
minutes, if condition 5A or 5B is not met, the high stage system failure will be
activated.
6. Once the cabinet temperature reaches –50°C, the*expansion tank solenoid is
opened (de-energized). The vacuum relief heater and mullion heater on double
door units, are energized and operate continuously until the cabinet is warmer
than –50°C.
7. Set point achieved, fans and compressors cycle off.
8. Steps 2 though 7 repeat (cycle).
*
Items or functions unique to this system
1.2 Expansion Tank Assembly and Solenoid Valve
Location:
Suction side of low stage system.
Purpose:
Tank assembly increases low stage system refrigeration
capacity. Prevents excessive low stage pressures at
temperatures warmer than –50°.
Operation:
The tank assembly solenoid valve is normally open. The
solenoid valve is energized (closed) when the control probe
senses temperature warmer than –50°C. The solenoid valve is
de-energized (open) when the control probe senses
temperature colder than –50°C.
1.3 Operating Pressure “High and low stage systems
”
The suction side pressure for both systems typically runs in a vacuum. Prior to
opening a system for a pressure reading, always purge your lines according to the
manufacturer’s recommended procedure. For further information, call Thermo Forma
Service Department.
230 Volt Freezers
Only the compressors require 230 volts. The remaining high voltage components
operate using 115 volts.