A L C H E M
Member of the Walchem Group
Five Boynton Road Hopping Brook Park Holliston, MA 01746 USA TEL 508-429-1110 FAX 508-429-7433
OPERATION
Back Pressure Requirement
In order for the PosiFlow Sensor to function, a minimum of 30PSI system pressure is required at the sensor. In cases
where there is little or no system pressure, the standard injection check valve supplied with each pump can be modified
with a high-pressure spring that adds approximately 50PSI. Contact your local distributor to order Part Number E90375.
Operation
Turn on the pump. The PosiFlow will not output a signal until the pump actually is moving liquid. For priming of the
pump, the PosiFlow sensor may have to be turned one-half or one full turn counter-clockwise to vent the air out the vent
connection.
CAUTION: Tubing should always be connected from the air vent back into the supply tank or suitable drain. Do not
submerge the air return tubing below the chemical surface level in the supply tank.
Once fully primed, close the air vent by tightening down the PosiFlow Sensor. The green LED on the PosiFlow should
now begin to flash OFF with each pump stroke and it will output a pulse simultaneously. The PosiFlow will continue to
output pulses as long as it senses pressure changes. If the pump loses prime or is air locked, the compression of air with
each pump stroke will not generate enough pressure for the PosiFlow to sense and it will not output pulses. Similarly,
excessive pressures will cause the pump to begin to stall and not generate enough pressure differential for the PosiFlow
to sense.
NOTE: If there is any trapped air, long lengths of flexible tubing, or any area of relief or expansion during a
deadhead situation, the PosiFlow may still keep sensing flow. This is more likely in C15/20 sized pumps.
Output Signal
The output signal from the PosiFlow simulates a contact closure. It can be used in any device that takes a non-powered
contact closure as a switch. It can also be used to drive another EH series pump.
The Walchem Web
WebWeb
WebMaster is designed to accept the PosiFlow Sensor signal. It both powers and reads the signal.
The Web
WebWeb
WebMaster will alarm a no flow condition after a customer-set time limit and will also totalize pumped volume
once the pump is calibrated.
In a similar manner, a PLC or other device can be programmed to interpret the PosiFlow signal in any number of ways.
TROUBLESHOOTING & MAINTENANCE
CAUTION: Do NOT disassemble the PosiFlow Sensor! There are no user serviceable parts inside and the components
can easily be damaged. Disassembly of the Sensor will void the manufacturer’s warranty.
Problem Possible Cause Corrective Action
No output pulses from the
PosiFlow Sensor
(Output pulse is not synchronous
with the pump stroke)
oIncorrect or disconnected wiring
oPump has lost prime (air-lock)
oPump is drawing in air
oDisconnected or cut tubing
oPinched or clogged tubing
oForeign material lodged in pump
oPosiFlow Sensor not tightened
down (in the air vent condition)
oNot enough back pressure
oDouble check wire connections
oUnscrew PosiFlow one-half turn to
vent air
oCheck the tubing and fitting
connections
oCorrect/Replace the tubing
oCorrect/Replace Tubing
oDisassemble/inspect/clean pump
head assembly
oTighten the PosiFlow Sensor by
turning clockwise by hand.
oCheck Injection Valve location and
system pressure. Install the High
Pressure Spring (E90375) if there
is little or no system pressure
Liquid Leakage from around the
PosiFlow Sensor
oO-ring seals on PosiFlow missing,
dislocated, or worn
oRe-install or replace the o-rings
E00098 PosiFlow Sensor
Instruction Manual
REVISION A 4/10/02
