7
HOW IT WORKS
DeltaPoint Jr. is a cooling water flow switch. It is comprised of a flow sensor, a shut-off valve, a check
valve, and all the associated wiring, complete in one package. When installed in the return leg, it can
detect changes in water flow due to cap loss or a break in the line, and shut off the supply/return water
legs.
The flow sensor utilizes the vortex shedding principle and has no moving parts to wear or clog. The water
strikes a bluff body, generating vortices (eddies) that move downstream. The vortices form alternately,
from one side to the other. A piezoelectric sensor housed in a sensor tube directly downstream of the
bluff senses the pressure zones created by the vortices. The sensor generates a frequency directly
proportional to the vortices (flow). The microprocessor measures this frequency and displays the output.
If installed according to the instructions in this manual, the 3-digit LED on the flow sensor displays the
water flow rate in the “return” leg in either LPM (liters per minute) or GPM (gallons per minute) with a high
degree of accuracy.
Mounted on the box is a two-position switch which is used to start the unit for normal operation, or to
bypass the solenoid valve by forcing it to remain open, even in case of a fault (during maintenance, for
example).
If water flow is present and is above the preset value, the flowmeter sends an OK TO WELD signal to the
weld controller, allowing the weld cycle to start. This is a 0V signal coming from the internal solid-state
relay. The shut-off valve is held open by the microprocessor during normal operation, and it closes when
there is either a flow fault or a power failure.
If a cap is pulled, the water flow in the “return” leg drops below the setpoint and the flow switch sends a
FAULT signal (24VDC) to the weld controller. It also shuts off the solenoid valve, thus stopping the water
flow in the “supply” leg. The check valve prevents water from flowing backwards from the gun arms,
effectively preventing a water spill from any source.
The rocker switch has two positions: START and BYPASS. START is a momentary switch that forces
the valve to open. It is typically held down at startup for a few seconds, until all the air trapped in the weld
gun arm circuit is removed and a steady stolid column of water is entering the flow switch. When the
green light inside the START switch is lit, it indicates that the water flow is above the flow switch alarm
setting and, therefore, is OK TO WELD. At this point the microprocessor takes over and continues to
keep the valve open during operation.
BYPASS is a toggle switch (push to turn on) and is used to force the valve open by overriding the internal
logic circuit. When in bypass, the flow sensor continues to monitor the flow in this case, as indicated on
the LED display, but the orange light (inside the BYPASS switch) is a visual reminder that the valve can
no longer be closed if flow fault occurs. The shut-off valve has an independent LED that is built into its
cable connector. When this LED is on it confirms the presence of coil power (valve should be open in this
case). The factory made a change on the operation of the “Bypass” switch mode. Please review below.
Serial Number 040817000 and greater.
The unit will not allow you in “Bypass” mode and ignore alarm fault if no water flow is present or leak
detected. Kit available (Part # “HBO”) to rework as described below.
Serial Number 051200100 and greater.
When the user activates the “Bypass” position of the switch, the unit will ignore the “Alarm Fault” signal
from flowmeter.
Please note: The user could weld without water to the weld guns in this mode.
SOLENOID INTERRUPT (Option H) is active on all units. It is used to remotely shut off the water flow
(Shut-Off Valve Coil) before the Associate changes weld gun arm electrodes.
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