Fluid Components International FLT Series - Manual (Page 31)

CHAPTER 3 - OPERATION FLUID COMPONENTS INTL
Doc. No. 06EN003246 Rev. B 3 - 13 FLTÔ Series FlexSwitchÔ
Detecting Dry Condition (adjustment with sensing element wet)
Verify that the sensing element is wet. If the status LED is off, turn the set point adjustment potentiometer clockwise
until the LED turns on. With the LED on, slowly turn the potentiometer counterclockwise one turn past the point at
which the LED just turns off. The potentiometer may have up to one-quarter turn of hystereses, therefore, if the mark
is overshot, the procedure should be repeated.
Detecting Wet Condition (adjustment with sensing element dry)
Caution: Give consideration to the fact that air or gas flowing over the sensing element may decrease the output
signal resulting in a false alarm. If the sensing element is exposed to air or gas flow in the dry condition, or
where the process media is highly viscous, make set point adjustments in the wet condition only.
Field adjustments made in the dry condition should be performed in the actual service environment or within a
condition that approximates that environment. Provision should be made for the worst case condition of air or gas
flow on the sensing element. If the status LED is on, turn the set point adjustment potentiometer counterclockwise
until the LED turns off. (If the LED cannot be turned off, the instrument must be set in the wet condition.)
With the LED off, slowly turn the potentiometer clockwise 1 turn past the point at which the LED just goes on. The
potentiometer may have up to one-quarter turn of hysteresis, therefore, if the mark is overshot, the procedure should
be repeated.
Signal Output for Level Applications
The output signal at P1 is lowest in water and highest in air. See Figure 3-4.
Temperature Applications
Note: It is reccommended not to use the instrument for a dual flow and temperature application in air or gas unless
the flow rate is greater than 1.0 SFPS. (The instrument may be used for a dual flow and temperature
application in liquids at any flow rate.)
When using the instrument for dual level and temperature applications, the temperature signal can be as
much as 50°F (28°C) high when the sensing element is in still air.
Turn the heater off for temperature only applications. To turn off the heater remove the heater control
jumper from the heater, control headder. The jumper may be stored on the control circuit by plugging it
across J12 and J14. Placing the jumper here will not turn on the heater.
1. Ensure that the instrument has been properly installed. Apply power the instrument and allow fifteen minutes
for the sensing element to become active and stabilize.
3. Establish the normal or expected temperature. Remove the enclosure cover to allow access to the control circuit.
Perform either the detecting increasing temperature or detecting decreasing temperature procedure shown below.
Detecting Increasing Temperature (high temperature alarm)
If the status LED is off, turn the alarm adjustment potentiometer clockwise until the LED turns on. With the LED
on, slowly turn the potentiometer counterclockwise one half turn past the point at which the LED just turns off. The
potentiometer may have up to one-quarter turn of hysteresis, therefore, if the mark is overshot, the procedure should
be repeated.
Detecting Decreasing Temperature (low temperature alarm)
If the status LED is on, turn the set point adjustment potentiometer counterclockwise until the LED turns off. With
the LED off, slowly turn the potentiometer clockwise one-half turn past the point at which the LED just turns on.
The potentiometer may have up to one-quarter turn of hysteresis, therefore, if the mark is overshot, the procedure
should be repeated.