TENNEY ENVIRONMENTAL
BOOST HEAT (Optional)
-
)
As an option, your chamber may be equipped with the boost heat feature which includes extra
heaters to provide rapid increases in temperature. The boost heat will automatically tum on if a
preset time delay relay times out, indicating that the desired temperature has not been
achieved.
As output
1CI-01 of the controller energizes the main heater bank, ICI-01 will at the same time
energize a time delay relay. When this relay times out it
will
energize a mercury relay, which
provides power to the boost heaters. A mechanical contactor is also provided which has it's
contacts wired into the power supply line to the boost heaters. This contactor is provided to
deenergize the heaters in the event of an over temperature condition.
BOOST COOLING (Optional)
USING LIQUID NITROGEN or
CARBON
DIOXIDE
As an option, your chamber may be equipped with a boost cooling system which is activated
by an event output from the Watlow 942 Controller. Cooling is achieved by injecting either LN,
or
CO,,
depending on the option purchased, into the chamber through a solenoid valve. To
activate the system the event must be turned on as explained in the Watlow
942
Controller
manual.
Event No.
1
is generally used for this function. However, a reference table defining the function
of each event is affixed to the control panel of each chamber. Please check this table before
1
operating the chamber.
Once enabled through the event, the cooling will turn on if a demand for cooling exists for a
preset time period.
A
timer connected to the time proportioned output of the controller "times
our' and energizes the cooling solenoid valve if the output is 100 percent "ON" indicating a
need for additional cooling.
When the desired temperature is attained and the controller heat output begins to turn on, the
boost cooling function will cease.
LN, systems are provided with a manually set flow adjusting valve provided to allow for
adjusting the flow to avoid incomplete evaporation at
valying
LN,
supply pressures. A setting
of
4
tums open generally provides good perfomlance at a supply pressure of 20 to
25
PSIG.
This valve may be readjusted as necessary to accommodate the supply pressure at the end
use point.
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