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7.11 Chiller Idle Requirement
7.11.1 Be idle for a short time:
There is no special requirement, follow the conventional procedure to check and start-up.
7.11.2 Be idle for a long time:
1. Chiller leak prevention
a. If chiller is idle for one month, suggest running purge every week.
b. If chiller is idle for more than one month, suggest charging nitrogen into chiller until chiller pressure is 103 kPa
higher than atmosphere. Before chiller start again, carry out the dehydration process to re-charge refrigerant.
2. Need to run the refrigerant pump to avoid potential corrosion.
3. Chemically treated Water circulation through the condenser and cooler at least once per week for 1-5
minutes (if they are not drained).
4. The purge operation and refrigerant pump operation should be controlled by the PIC 5+ controller to au-
tomatically address these items. The water pumps would need to be manually operated by the customer.
8. PURGE OPERATION SEQUENCE
Refer to fig 53. For the Purge Operation Diagram.
8.1 Purge Operating Modes
Purge system has two operation modes: Auto and Manual.
You can choose it in Configuration Menu->Lab Test Forced->Purge Forced. Select “0” means Auto mode. Select
“1” or “2” means Manual mode, where 1 means purge will be active regardless the purge active condition, “2”
means you can control purge related valves manually.
8.2 Non-condensable Gas Pump Out
When purge tank is full of non-condensable gas, the purge compressor inlet temperature drops to -15 °C, so the
discharge valve and pump out valve open, vacuum pump starts to pump out the non-condensable gas inside
purge tank.
8.3 Carbon Tank and Regeneration Subsystem
If the carbon filter is saturated with refrigerant, the heater can heat carbon filter to about 127 °C. The condenser
valve and cooler valve is closed during this time. Only the pump out valve and regeneration valve is open.
Meanwhile, the vacuum pump will operate at intervals. Regenerated refrigerant is pumped to cooler. After about
120 minutes, the regeneration process stops. However, purge system will wait for another 4 hours to let carbon
filter to cool down before it can operate normally.
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