22
Table 5. Resistance / Temperature Specication
Temperature °F Ohms Temperature °F Ohms
104 5,320 32 32,650
86 8,060 23 42,330
77 10,000 14 55,330
68 12,490 5 72,950
59 15,710 -4 97,070
50 19,900 -13 130,410
41 25,400 -22 176,960
Evaporator Fans Shut Down By
Operators
In some installations, it is desirable to shut off the
evaporator fans for product loading. This is easily
accomplished on Beacon II by wiring a single pole
switch (SPST) between the terminals on the Beacon II
board marked “SERVICE” and “COM”. Closing this
switch will cause the system to pumpdown and shut off
the compressor and the evaporator fans. The switch must
be reopened before the system will restart. This SPST
switch and wiring is eld supplied and eld installed.
Power Failures
In the event of a power failure, Beacon II will
automatically close the expansion valve to prevent
refrigerant from migrating throughout the system. After
power returns, with 24 VAC at the board, the system
will restart in the cooling mode after the 4-minute hold
off period. The alarm contacts will close triggering any
alarm device that is connected.
Spare Sensor Terminals
Beacon II provides a set of input terminals for customers
who may want to monitor an additional temperature or
items such as Product Temperature. This input terminal
requires a signal from a thermistor which meets the
temperature/resistance values in Table 5 below.
If a product temperature simulator is used, it must meet
the resistance/temperature specication listed in Table 5.
The temperature range for this input is -30°F to 140°F.
Sensors on the Beacon II system, as supplied, will not
simulate product temperature.
This input can be monitored on the LED display by using
the “MONITOR” button and scrolling theSPt. The values
displayed will be the temperature of the spare sensor.
Checking Sensors
DO NOT REMOVE SENSORS FROM COIL FOR
CHECKING. Use the monitor button to display the value
the sensors are reading on the LED (suction temp. SCt,
defrost temp. dFt or room temp.). Compare this value to
the measured value with a thermometer at each of these
points. If they do not match, change the sensor.
The sensors can be checked for their proper operation
by placing it in a cup of ice water. Stir the ice water and
measure the resistance of the sensor. At 32°F the resistance
should be 32,650 ohms. If it is higher or lower by 1,000
ohms approximately, the sensor should be replaced.
Beacon II Controller
To Next Page
Loading...
Need help?
General
