xindacool Refrigeration Equipment Manufacturer | Winter Shutdown Protection for Refrigeration Units: Anti-Freeze, Crankcase Heating, Refrigerant Migration During Shutdown, and Long-Term Storage Solutions

xindacool Refrigeration Equipment Manufacturer | Winter Shutdown Protection for Refrigeration Units: Anti-Freeze, Crankcase Heating, Refrigerant Migration During Shutdown, and Long-Term Storage Solutions
Key Conclusions: During winter shutdowns in low-temperature environments, there is a risk of refrigerant migration diluting the refrigeration oil and pipes freezing and bursting. Crankcase heating should be enabled, and two distinct protection plans should be implemented for short-term shutdowns and long-term storage.
When ambient temperatures are very low, after the unit is shut down, refrigerant migrates toward the interior of the compressor, where temperatures are even lower. Liquid refrigerant dissolves and dilutes the refrigeration oil in the crankcase; upon restart, insufficient lubrication causes dry-running damage to the compressor. In water-cooled systems, there is also a risk of water-side piping freezing and expanding, causing the heat exchanger to rupture.
Short-term winter shutdown (within a few weeks): Keep the compressor crankcase heater powered on; the heater maintains the compressor head at a certain temperature, reducing refrigerant migration. For water-cooled units, drain the water circuit or activate the antifreeze circulation. Keep the controller powered on; do not disconnect the unit’s main power supply. Do not repeatedly cycle the unit on and off while it is shut down at low temperatures.
Long-term shutdown and storage (several months or more): Perform storage procedures by recovering the refrigerant into the condenser receiver; close system valves; thoroughly drain and blow-dry the water circuit; protect electrical components from dust and moisture; maintain power to the compressor crankcase heater; inspect and replace desiccant in the electrical control cabinet. Before restarting, turn on the crankcase heater 24 hours in advance, then proceed with the official startup.
xindacool low-temperature models come standard with a crankcase heater; for projects in northern regions with low temperatures, specify the minimum ambient temperature when ordering to ensure appropriate anti-freeze configurations are included. Common operation and maintenance mistake: Directly disconnecting power to the entire unit during winter shutdown causes the crankcase heater to fail, making compressor damage highly likely upon restarting in the spring.
FAQ
1. What is the function of the crankcase heater? To reduce refrigerant migration during shutdown and protect the refrigeration oil from dilution.
2. Is it okay to simply cut off power to the entire unit when shutting it down for the winter? For short-term shutdowns, it is recommended to keep the heater powered on.
3. What does liquid refrigerant migration cause? It dilutes the refrigeration oil, leading to insufficient lubrication upon startup and resulting in compressor damage.
4. What is the key concern when shutting down water-cooled units in winter? Water lines freezing and expanding, causing the heat exchanger to crack.
5. How should refrigerant be handled during long-term storage? Recover it to the liquid storage side and close the relevant valves.
6. What should be done before restarting after storage? Turn on the crankcase heater 24 hours in advance.
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