Walchem Metering Pumps

Functionality and controllability: In addition to manual control, the F control module is only capable of external 1:1 digital control. It has an external STOP input that can be configured to either NO or NC and the F control module has two outputs (contact closures only), one that outputs pulses in synch with the pump stroke and one which correlates with the STOP input.

The Y control module can run via manual control as well as various external control methods (programmable or fixed analog input or digital input with Multiply or Divide features) It also has a STOP input, but it is not selectable NO/NC. The Y module also has two relay outputs and can be configured in a variety of configurations. Additionally, the PosiFlow sensor can be connected directly to the Y control module and it can be programmed to stop the pump and output an alarm if no flow is detected. The Y control module has several other features that are programmable including a calibration and output view in volume (GPH).

An Instruction manual is supplied with every pump. Most pumps also come with tubing, ceramic weight, injection valve and foot valve. EW pumps with Y Control Modules and EK pumps also come with a connector for input control. Pumps supplied with NPT fittings do not include tubing, weight, or either valve.

Tubing is an integral part of the pumping system and the connections between tubing and fittings is critical. Walchem recommends using Walchem supplied tubing, however other tubing can also be used. Caution has to be used when using other tubing as tolerances and pressure ratings can vary.

Walchem solenoid metering pumps only use two standard-size tubing - 3/8"ODx1/4"ID (for pump sizes 10, 15 and 20) and х_"ODx3/8"ID (for pump sizes 30, 35, 45 and 55).

Only the EZB-Timer control module uses a battery, however the battery is used for the time function required in the timer module. All pumps, including the EZB-Timer use EPROM memory to store the current settings. This memory is retained during indefinite loss of power. As with any electronic equipment, power surges or large EMI bursts could disturb the memory, but it is not a common occurrence.

From within any menu or programming, pressing the STOP/START key until the pump starts running manually will get the pump operating in the manual "run" mode. From there, the pump can be stopped by pressing the STOP/START key again, entering the "WAIT" mode.

All pump series except the EZB Series pumps have an external input (non-powered contact closure) that can be used to STOP the pump. As long as the STOP input is closed, the pump will remain stopped.

Many of the Walchem parts are interchangeable, however not all of them. The exploded views of the liquid ends in the instruction manuals and online will help highlight interchangeability. However, if you are unsure, contact your distributor for further help.

"Parts kits" are available for every liquid end option and are basically comprised of the elastomeric parts including the diaphragm and valve guide assemblies. Complete head assemblies can also be ordered as spares. These can be used to change over the liquid end to change materials of construction - or to replace damaged parts.

Typically, the pump will sound much louder than when pumping normally against pressure. Looking at the discharge point of the pump or tubing is a 100% sure way to check for pumping. Non-moving pockets of air in the suction or discharge line is another good way to tell whether or not there is chemical moving. The easiest way, solving most of the problems at the same time, is to open up the Manual Air Vent and check that the pump is pumping out the air vent.

The EW-Y and EHE are the only control modules that accept analog signals. Neither of these pump models has the power output to supply the power for a 4-20mA transmitter. If power is required, an external power supply (12VDC preferred, but not to exceed 24VDC) is required to be installed in series.

For the EW-Y pumps, a 5-pin circular connector is required (E90495, supplied with the EW-Y module). The Analog signal is connected with the negative side (usually black) wired to the center pin (PIN 5) and the positive signal (usually red) has to be wired to the Analog Input pin (PIN 1). NOTE: Orientation of the connector should always be lined up to connect with pump - check numbers molded into back of connector or PIN numbers to be sure.

For the EHE pumps, the Analog signal is connected with the negative side (usually black) wired to the common terminal (position 8) and the positive signal (usually red) has to be wired to the Analog Input terminal (position 5).

The EW-F and EW-Y are the only two control modules that have output capability. Both of these pumps can output a pulse synchronous with the operation of the solenoid unit. They can also each output a STOP signal when an external Stop Input stops the pump - this is somewhat opposite but can be interpreted in a similar manner.

In addition, the EW-Y pump can output a steady closed contact whenever the pump is operating in the Manual or External modes, regardless of pump speed. This is used more to remotely monitor whether the pump is in an operating condition or has manually been stopped.

Finally, the PosiFlow sensor can be attached directly to the discharge side of the E-Series pumps and output signals matching pulse for pulse the output pulses of the liquid coming out of the pump. The EW-Y control module can power and take the PosiFlow pulses in and monitor the pulses against the solenoid pulses. If too many pulses are missed compared to the pump strokes, the EW-Y can then output an alarm or similar signal.

Open up the Manual Air Vent Valve (make sure it is plumbed with tubing back to the supply tank) and operating the pump until all the air is purged from the suction line and within the pump head. Once it is primed, close the MAVV and resume operation. If it loses prime again, the pump head should be disassembled and inspected for bad seals, gaskets trapped under o-rings, debris obstructing a seal, etc. Reassemble with new parts from a parts kit and reprime.

The EK-Series pumps are rated to IP67 and can be used directly in all weather conditions.
All the other pumps are rated IP65 and can be used outdoors, but should be shielded from direct elements (rain, sleet, snow, sun)
For all the pumps, care should be taken not to allow the chemical to freeze in the pump head or allow direct sun to deteriorate the tubing quality.