Adjustment And Troubleshooting; Condenser Modulating Valve - Cornelius UC 700 Series Installation & Service Manual

UC 700 Series Continus-Flow Icemaker Installation/Service Manual
A
DJUSTMENT AND
When troubleshooting the expansion valve you must first be sure you have adequate water flowing into evaporator,
a clean condenser, unit is properly ventilated, and system is properly charged and free from any restrictions. Also
be sure compressor is operating properly.
Second, take reservoir water temperature and air temperature from condenser inlet and determine at what
pressure unit should be running. Machines are equipped with thermostatic valves, there is NO adjustment. If
correct pressure cannot be obtained, first be sure system has time to stabilize 10–15 minutes. Second, be sure
sensing bulb is located at 12:00 position on outlet side of evaporator about 3–4 inches away from evaporator and
be sure to insulate well and clamp tightly to tubing. If system pressures are still not adequate, take a second water
and air temperature reading and go over other parts of system for possible problems. If proper charge is
questionable evacuate and recharge to nameplate and leak check. If valve still malfunctions replace valve.
When replacing valve be sure to bleed refrigerant gas from low side port so as not to lose refrigerant oil. Use
general refrigerant system practices when replacing and recharging unit. After new valve is in place, go through
previous monitored adjustments and troubleshooting to be sure valve is functioning properly.
NOTE:Units with thermostatic expansion valve—valve is located on bottom refrigerant line. Sensing bulb
is located on top refrigerant line. On water cooled units adjust condenser modulating valve before
troubleshooting expansion valve.
!
CAUTION:
Very High discharge pressure is present in system. Quick disconnects on you gauges will minimize danger and loss
of refrigerant. Comply with federal regulations for reclaiming refrigerant.
C M
ONDENSER ODULATING
The reason for using a water modulating valve is to supply the correct amount of water to the condenser. and to
maintain a proper operating pressure to refrigeration system high side.
The flow of water through the valve is increased as the high side pressure rises and is decreased as high side
pressure lowers.
To calibrate the amount of water flow with the refrigeration system high side pressure, turn adjustment screw
located on end of valve opposite of bellows. Turn screw counterclockwise to raise opening point or clockwise to
lower opening point. Opening point of valve should be set to maintain proper operating pressure in refrigeration
system high side. Refer to Pressure Chart on. Closing point of valve should be set low enough to close valve during
compressor stand–by periods.
NOTE:Cold water will absorb heat faster than warm water. The water flow will therefore automatically
increase as inlet temperature increases.
Figure 5. Expansion Valve
Publication Number: 630460127
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ROUBLESHOOTING
V
ALVE
Figure 6.
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Adjustment Screw
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