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Brand: Walchem
Walchem EWN-Y Series Electromagnetic Metering Pump
Description
A compact high-speed solenoid pump with a universal-voltage digital controller
The EWN-Y series electronic metering pumps offer high-speed dosing with more standard features than earlier models. Outputs reach 6.7 GPH (25.2 L/h) at pressures up to 290 PSI (20 bar), and the pumps run up to 360 strokes per minute with adjustment in 1 spm steps. Adjustable stroke length further refines the output, and Walchem notes that the pumps are quiet, compact, prime in seconds and hold prime reliably.
The multi-function digital controller is universal voltage, so the same pump can be used anywhere in the world. It supports scalable analog control, digital input with multiply and divide, external stop, batch control, automatic output control with the EFS sensor, and basic speed or stroke-length control. The display can show flow-rate units or percent speed.
Technical specifications
| Parameter | Specification |
|---|---|
| Drive units | EWN-B (20 W average); EWN-C (24 W average) |
| Diaphragm sizes | 09 (8 mm), 11 (10 mm), 16 (15 mm), 21 (20 mm), 31 (30 mm), 36 (35 mm) |
| Max output, standard pumps | B11 0.6 GPH; B16 1.0; B21 1.6; B31 3.2; C16 1.3; C21 2.1; C31 4.3; C36 6.7 (VC/VE/PC/PE) or 6.5 GPH (FC/SH/TC) |
| Rated discharge pressure | B11 150 PSI; B16 105; B21 60; B31 30; C16 150; C21 105; C31 50; C36 30 |
| Max pressure | B11 203 PSI; B16 116; B21 73; B31 30; C16 174; C21 116; C31 50; C36 30 (PVC type 174 PSI maximum) |
| High-pressure options | H: 250 PSI (B11/C16 PC/PE/PA/SH); H2: 290 PSI (B11 PC/PE/PA/SH) |
| Stroke rate / length | 0.1 to 100 % (1 to 360 spm); stroke length 20 to 100 % (0.2 to 1.0 mm, or 0.25 to 1.25 mm) |
| Output per shot | 0.02 to 0.11 mL (B11) up to 0.23 to 1.17 mL (C36) |
| Wet-end materials | Pump head PVC, GFRPP, PVDF, PCTFE, 316SS or Hastelloy C276; diaphragm PTFE; valve seats and balls in FKM, EPDM, PTFE, AFLAS or alumina ceramic by liquid-end code |
| Electrical | 100 to 240 VAC ±10 %, 50/60 Hz; 0.8 A (EWN-B) or 1.2 A (EWN-C) maximum |
| Liquid temperature | -10 to 40 °C for PVC liquid ends; -10 to 60 °C for GFRPP, PVDF and stainless steel |
| Ambient | 0 to 50 °C; up to 85 % RH non-condensing |
| Shipping weight | EWN-B 4.5 kg; EWN-C 5.5 kg (SH liquid ends up to 50 % more) |
| Certifications as printed | WQA tested and certified to NSF/ANSI/CAN 61; tested by Intertek to UL and CSA standards |
Reading the model code
The code takes the form EWN, drive unit, diaphragm size, liquid end, power code, controller function code and options. For instance EWN-B11VCUY decodes as the B drive unit, 10 mm diaphragm, VC liquid end, 115 V US plug and standard Y controller. Power codes are U for 115 V with a US plug and 2 for 230 V with a US plug. Options include H and H2 for high-pressure versions, C for a high-compression version with an auto-degassing valve, A for an auto-degassing valve and M for a multifunction valve; the tubing connection is 1/4 x 3/8 inch on the small sizes, 3/8 x 1/2 inch on B31, C31 and C36, and 1/4 FNPT on the stainless SH versions.
Wet-end choices matter for chemical compatibility. Wetted materials include PVC, glass-fibre reinforced polypropylene, PVDF, PCTFE, 316 stainless steel and Hastelloy C276, with valve seats, balls and gaskets in FKM, EPDM, PTFE, AFLAS or alumina ceramic according to the liquid-end code; the brochure’s materials table lists each combination.
Typical duties and what to confirm
The EWN-Y is used for chemical injection in water treatment, from hypochlorite and acid dosing to inhibitor and coagulant feed in small and mid-size systems. Because the high compression ratio helps with off-gassing products, the pumps are suited to sodium hypochlorite when the right liquid end is selected.
Confirm the required flow at the actual back pressure, the chemical and its temperature, the tubing size, the control signal (pulse, analog or batch), and whether a high-pressure H or H2 option is needed. The brochure notes that maximum output is stated for clean water at rated discharge pressure and may be lower at pressures above the rated value, and that PVC type pumps are limited to 174 PSI maximum.
Documents and quotation
The EWN-Y brochure is attached. For other chemical feed products, see Pumps or the Grundfos DME digital dosing pump. Provide the full model code, chemical and quantity in the RFQ form.
Datasheets & Documents
- Brochure Walchem EWN-Y Series Brochure Download
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About brand
Walchem is an American brand of water treatment controllers and electronic metering pumps, based in Holliston, Massachusetts. A long association with the Japanese pump maker Iwaki led to the Iwaki America joint venture, and the Walchem business is now part of Iwaki America. Walchem controllers manage chemical treatment of cooling towers, boilers and process water, with remote monitoring and alarms.
Seven Star LLC is an independent supplier in Muscat. We list Walchem controllers and pumps for cooling towers, boilers and water treatment in Oman and the GCC.
Walchem company profile
| Headquarters | Holliston, Massachusetts |
|---|---|
| Group | Iwaki America (Iwaki Co., Ltd.) |
| Applications | Cooling towers, boilers, wastewater and process water |
| Product families | Intuition-6 and Intuition-9 controllers, W100 and W600 series controllers, EHE electronic metering pumps, sensors and flow switches |
Walchem product series
Controllers include the W100W cooling tower and boiler controller and the Intuition-6 and Intuition-9 water treatment controllers with multiple sensor inputs and outputs.
Metering pumps include the EHE and EWN-Y electromagnetic pumps and the IX digital diaphragm pump.
Controllers measure conductivity, pH, ORP and other parameters and control blowdown and chemical feed pumps automatically. Electromagnetic metering pumps dose small, accurate volumes of chemical and can follow a pulse or 4-20 mA signal.
Where Walchem products are used
Cooling tower blowdown and inhibitor dosing, boiler water treatment, disinfection and pH control in water and wastewater.
Walchem products we list
Ordering Walchem products: what we need
Send the model code, the sensors and outputs needed, the chemical, flow and pressure for pumps and the supply voltage.
Facts checked against Hydraulic Institute and Iwaki America company profiles, October 2026.
Browse Walchem products by category: Liquid Analytical Systems, Pumps.
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Frequently Asked Questions
What flow and pressure does the EWN-Y reach?
Up to 6.7 GPH (25.2 L/h) and up to 290 PSI (20 bar) with the high-pressure option.
What supply voltage is needed?
The universal controller accepts 100 to 240 VAC, 50/60 Hz.
Which control modes exist?
Analog scaling, digital input with multiply and divide, external stop, batch control, EFS-sensor auto output and manual speed or stroke control.
Which liquid-end materials are offered?
PVC, glass-fibre reinforced polypropylene, PVDF, PCTFE, 316 stainless steel and Hastelloy C276, with FKM, EPDM, PTFE or AFLAS seals by code.
Does it carry a drinking-water certification?
Walchem prints WQA testing and certification to NSF/ANSI/CAN 61 for the series.
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