The pressure reading should correspond to a saturated temperature reading about 10 to 15 degrees colder than the circulating water temperature, depending on the peculiarities of your particular chiller. Pressures correspond to saturated temperatures, which may be thought of as the boiling point of the refrigerant. Note: on some compressor models the oil pump directs a stream of oil at the compressor sight glass. Once suction pressure stabilizes and temperature pull down begins, the oil level in the sight glass should be about half full. The compressor should start when refrigerant pressure reaches the cut-in setting on the low pressure switch.Īfter you have started the unit, you may see foaming in the compressor oil sight glass. This setting should never allow the compressor to pump into a vacuum the suction gauge pressure at cutout should always be above zero. If the oil pressure reading matches the suction pressure, there is no net oil pressure, and unit should be shut down immediately.ĭont wait for the oil failure switch to do this, as it operates on a time delay. It should read significantly higher that the suction pressure gauge. If the compressor comes on, allow it to pump down the residual refrigerant left in the chiller before energizing the liquid line solenoid. If in addition the indicator in the liquid line sight glass shows.Īssure that the water in the tank is circulating through the chiller only (on bypass valves left open) and that the condenser pump is running raw seawater through the condenser. If the suction gauge reads zero, even though there is pressure reading on the discharge gauge, there might be a leak in the chiller. If they all read zero, the system refrigerant charge has leaked out. Some residual refrigerant pressure should read on the gauges. If oil is not visible in the compressor sight glass, dont start the compressor until you can add more.Īlso check pressure gauges, paying particular attention to the suction pressure gauge. Keep in mind that refrigeration oil is highly refined and under normal operation conditions is very pale yellow. If you cant see a level it is sometimes difficult to tell if the crankcase oil level is low or is overfilled. So, if your system is operating with bubbles in the sight glass and there is a large load on the system, no worries. This overcharge often goes undetected since TXV systems typically have receivers that store this excess charge.
Clear sight glass in refrigeration system full#
If the unit has been off for an extended period, energizing the heater overnight is good practice. In the case of a hot pull down, charging to a full sight glass will result in a system overcharge.
On some units the heater is energized when the control power circuit breaker is made.
Condenser shell cooler evaporator shell warmer (Centrifugal Chiller) at low condensing temperatures, refrigerant migrates to evaporator 20.ĭecreasing condenser water flow, which decreases the heat exchange capacity of the condenser, increases the compressor discharge pressure.
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