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Sight Glass/Moisture Indicator
On the condensing units, there is a sight glass located directly
inside the front cover. This glass will communicate many
things about the system's operating condition.
1. The glass should show foam upon start-up. This should
clear after a few minutes of running. If it doesn't clear,
the charge is low. If there was no foam upon start-up, the
system may contain no refrigerant. The glass does not
have to be full to operate correctly.
A. Sight glass is clear, no cooling = no refrigerant in system
B. Sight glass is clear, cooling = refrigerant charge is good
C. Sight glass is white or foamy = refrigerant charge may
be low
2. There is a colored media around the hole inside the glass.
When it is green, the system is dry. When it is yellow,
the system is wet. Wet systems are systems that contain
moisture. This may not allow your system to work correctly.
See the Troubleshooting section.
3. Upon unboxing the condensing unit, the sight glass may
be yellow. This generally occurs because the media needs
a liquid fl ow over it to correctly measure the moisture con-
tent. Hook up the unit, and let it run for about 30 minutes.
The sight glass should turn green.
Thermostat
The thermostat controls the operation of the condensing unit
based on box temperature. Set it to a point that conforms to the
box and system design. See table with setpoint range in CPV
section above. One thermostat is required for each box. Ther-
mostats may be located on the condensing unit, or remotely.
The thermostat should be set to operate for the design condi-
tions. If the box is designed to be a 40°F/4.4°C icebox, it will do
no good to set the thermostat at 15°F/-9.4°C. This is because
the system is being asked to do what it cannot, and the
extended run time will result in a shorter unit life. See Figure 5.
Thermostat bulb or thermistor should be mounted midway
to two-thirds of the way up a side wall in the box. Mount it in
a position where it can sense average box temperature. Do
not mount bulb or thermistor near the box opening. Mounting
brackets are available from your dealer.
L-2091 Installation
Refrigerant Charge
All Systems
The system is relatively charge insensitive due to the large
receiver that allows the condensing unit to be charged with
enough refrigerant to handle most normal plate and line con-
fi guration. No further charging is required for most applications.
Linesets and Plates
These have been evacuated and vapor charged.
Repair
If the charge is lost, or is suspected to be incorrect, the system
must be evacuated and recharged with the proper amount of
R-134a. See "Recharging the System."
See Figure 16 for a typical refrigerant pressure-temperature
chart.
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English
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