
GENER
AL INFORMA
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PR
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T INFORMA
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SY
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INTEGR
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ORDERING INFORMA
TION
*Crankcase heater
The belt crankcase heaters are designed to
protect the compressor against off-cycle
migration of refrigerant.
Additional heater power or thermal insulation
might be needed in case of ambient temperature
below -5°C (23°F) and a wind speed above
5m/second (16.4 feet/second).
The heater must be turned on whenever all the
compressors are off.
Cranckcase heater accessories are available from
Danfoss (see section “Accessories”).
**Liquid line solenoid valve (LLSV)
A LLSV is used to isolate the liquid charge
on the condenser side, thereby preventing
against charge transfer to the compressor
during off -cycles. The quantity of refrigerant
on the low-pressure side of the system can be
further reduced by using a pump-down cycle in
association with the LLSV.
***Pump-down cycle
By decreasing pressure in the sump, pump down:
• Evacuates refrigerant from oil
• Set the sump saturating pressure much
lower than ambiance temperature and due
to that, avoid refrigerant condensation in the
compressor.
• Pump-down must be set higher than 1.8 bar(g)
/ 26 psig.
For more details on pump-down cycle see
section “Control Logic”.
Manage off cycle migration
Optimum
location area
SY
STEM DESIGN
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