WALCHEM EWP SERIES METERING PUMPS

Precise Dosing. Dependable Performance. Flexible Controls.
High‑accuracy chemical metering pumps for industrial water treatment and process dosing.

The Walchem EWP Series, manufactured by Iwaki (Japan) and distributed under the Walchem brand, is a next‑generation family of solenoid‑driven metering pumps designed for precise chemical dosing in industrial water treatment and process applications. All standard models operate at 360 strokes per minute, feature a high compression ratio for reliable priming and venting, and are housed in a rugged IP66‑rated enclosure. The series includes two control platforms—EWP‑L and EWP‑R—built on the same mechanical drive and liquid‑end architecture.

Why Choose the EWP Series?

The EWP Series combines Iwaki’s mechanical engineering with Walchem’s control and integration expertise.

• Successor platform to multiple legacy Walchem E-Series pumps
• High‑resolution feed at 360 spm
• Excellent priming and venting performance
• Wide turndown ratio
• Rugged IP66 enclosure
• Flexible mounting options
• Broad material compatibility
• Engineered for longevity and durability

Performance Range:

• Maximum flow: 6.7 GPH (25 L/h)
• Minimum flow: 0.4 GPH (25 mL/min)
• Maximum pressure: 300 PSI (20 bar)
• Stroke rate: 360 spm
• Turndown ratio: 1800:1
• High compression ratio improves priming and venting, especially with off‑gassing chemicals

Electrical Specifications:

Power Supply: 100–240 VAC, 50/60 Hz
Average Power: 13 W (A/B heads), 23 W (C–F heads)
Max Current (115 VAC): 0.8 A / 1.1 A
Max Current (230 VAC): 0.4 A / 0.5 A
Auxiliary Power (EWP‑R only): 12 VDC, 30 mA
Shipping Weight: ~7 lbs (plastic heads), ~9 lbs (SS heads)

Control Variants:

EWP‑L (Simple Function Type)

• Manual stroke rate control (0–100%)
• External proportional control: 4–20 mA or pulse input (0–6 Hz)
• Two‑knob interface (stroke rate + mode selector)
• Status LEDs (green = running, red = STOP input)
• STOP input (dry contact)
• Power: 100–240 VAC, 50/60 Hz

EWP‑R (Standard Type)

• Backlit LCD display
• Multicolor LED status indicator
• Expanded proportional control modes: ANA.P, ANA.V, PLS.V
• MULTI / DIV (×1–9999 / ÷1–9999)
• Batch and interval batch modes
• PRIME, AUX, Pre‑STOP, STOP, Interlock
• Alarm output (open collector)
• Keypad lockout
• Integrated 12 VDC auxiliary power
• Power: 100–240 VAC, 50/60 Hz

Key Engineering Features:

• High compression ratio for reliable priming and venting
• Dual bearing support for long diaphragm life
• Dual check valve assemblies with precision ball guides
• Rugged IP66 enclosure (dust‑tight, water‑resistant)
• Compact footprint suitable for cabinets and OEM skids

Liquid End & Material Options:

Pump Head Materials: PVC (VC, VE, VF), GFRPP (PC, PE, PA), PVDF (TC, TA, FC), 316SS (SH)
Valve Balls: Alumina ceramic (CE), PTFE (VF), PCTFE (PA, TA), Hastelloy C276 (SH)
Valve Seats: FKM, EPDM, AFLAS, 316SS (SH)
Diaphragm: PCTFE bonded to EPDM (all models)
Gasket: PTFE (all models)

Connection Types:

07 – Tubing, 1/4" ID × 3/8" OD
08 – Tubing, 3/8" ID × 1/2" OD
10 – Threaded, 1/4" FNPT
11 – Threaded, 1/2" MNPT

Note:
The EWP Series supports both tubing connections (for flexible chemical feed tubing) and threaded NPT connections (for rigid pipe or adapters). Specific suction/discharge geometries vary by wet‑end material and are detailed on individual product pages.

Special Options Available:

A – Auto Degassing Valve (B/C/D sizes, VC/VE)
F – 1st‑Gen AAW Installed (−40 PSI derate)
H – High Pressure (up to 290 PSI)
K – No Manual Air Valve (SH only)
M – Multi‑Function Valve (not for FC/SH)
12 – Adds ADV‑VCH‑7 to TC pumps
W – High Pressure + No Manual Air Valve (SH only)
N – No special options

Applications:

• Cooling towers
• Boilers
• Wastewater treatment
• Disinfection (NaOCl, PAA, etc.)
• pH/ORP control
• Industrial process dosing
• OEM skids and compact systems

Installation & Mounting:

• Removable secondary base supports wall or surface mounting
• Tool‑free pump removal
• Install level for accurate dosing
• Requires a solid, vibration‑free foundation
• IP66 enclosure protects against spray, but pump must be kept dry
• Not intended for direct outdoor exposure
• Flooded suction recommended for off‑gassing chemicals

Legacy Model Replacement & Cross‑Series Compatibility Details:

Walchem (Iwaki) is transitioning several legacy metering pump families to the EWP platform beginning in 2026.

EWP‑L replaces:
• EZ Series (scheduled end: Spring 2026)
• EJ Series
• Uses the same liquid ends as EZ/EJ/EWN
• Similar pricing with expanded features
• Shares most repair kits with legacy models

EWP‑R replaces:
• EWN‑R (no longer available)

EWP‑Y will replace:
• EWN‑Y (transition planned for late 2026)

Full model‑to‑model compatibility is documented on individual product pages.