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NOTES
:
1. Approved oil from two suppliers can be mixed, although they have slightly different viscosity.
2. Lubricant from either supplier can be furnished when ordering by Daikin part number.
7.4
Hot Gas Bypass
All units can be equipped with an optional hot gas bypass system that feeds discharge gas directly into the evaporator
when the system load falls below 10% compressor capacity.
Light load conditions are signaled by measurement of the percentage of RLA amps by the MicroTech 4 controller. When
the RLA drops to the setpoint, the hot gas bypass solenoid valve is energized, making hot gas bypass available for metering
by the hot gas regulating valve. This hot gas provides a stable refrigerant flow and keeps the chiller from short cycling
under light load conditions. It also reduces surge potential on heat recovery units.
The factory setpoint for bringing on hot gas bypass is 40% of RLA.
7.5
Condenser Water Temperature
When the ambient wet bulb temperature is lower than design, the entering condenser water temperature can be allowed
to fall, improving chiller performance.
Daikin chillers will
start
with entering condenser water temperature as low as 55
F (42.8
C) providing the chilled water
temperature is below the condenser water temperature.
The minimum
operating
entering condenser water temperature is a function of the leaving chilled water temperature and
load. Even with tower fan control, some form of water flow control such as tower bypass must be used.
