Danfoss 032U7125 EV220B 25 G1 Brass NC Solenoid Valve Body EPDM

A G1 brass servo-operated solenoid valve for water and neutral media

032U7125 is the Danfoss EV220B 25 solenoid valve body: normally closed, brass, G1 (DN 25) internal connection to ISO 228-1, with an EPDM seal and a Kv value of 11 m3/h. The EV220B 15-50 is a universal indirect servo-operated 2/2-way valve for water, steam, oil, compressed air and gases; the brass NC version with EPDM is the variant for water and drinking water. The Danfoss store lists 032U7125 as a valve body to be fitted with a separate coil, so the coil voltage must be chosen on the order.

Technical specifications

How the valve works and which G1 variants exist

When the coil voltage is disconnected the armature spring presses the valve plate against the pilot orifice. Pressure builds across the diaphragm through the equalizing orifice and closes the main orifice. When voltage is applied the pilot orifice opens, the pressure across the diaphragm falls and the diaphragm lifts clear of the main orifice. The valve stays open as long as the minimum differential pressure of 0.3 bar is maintained. Because the valve is servo-operated it needs that minimum pressure difference and is not suitable for zero-pressure service. A built-in filter protects the pilot system and water hammer is damped.

The data sheet parts program lists the neighbouring G1 variants, which is useful when the exact specification is uncertain: 032U7172 (brass NC with NBR seal), 032U7126 (brass NC with FKM seal), 032U7127 (brass normally open with EPDM, 0.3 to 10 bar), 032U5825 (DZR brass NC with EPDM) and 032U8502 (stainless steel NC with EPDM). 032U7125, the subject of this page, is the standard brass NC EPDM version. FKM seals are limited to 10 bar differential pressure and 0 to 100 C; for water with FKM the data sheet gives a maximum of 60 C.

Installation and ordering notes

Danfoss recommends a 50 mesh filter (297 microns) in front of the valve. In water applications the valve should be exercised at least once every 24 hours to reduce calcium carbonate and oxide build-up. For water Danfoss suggests hardness of 6-18 dH, conductivity of 50-800 uS/cm and avoiding stagnant water above 25 C to limit dezincification of brass; use the DZR or stainless steel versions for slightly aggressive or aggressive media. Order the coil separately, for example the 24 V DC BG024DS clip-on coil 018F6857.

Key features of the EV220B 25 brass body

• Servo-operated (indirect) design: the line pressure itself does most of the work of opening and closing the 25 mm main orifice, so a relatively small coil can switch a G1 line.
• Normally closed function, which means the valve shuts automatically on loss of power, a useful fail-safe behaviour for filling, dosing and irrigation lines.
• EPDM diaphragm and seals, the usual elastomer choice for hot and cold water, but not for mineral oil or fuel.
• Damped closing to reduce water hammer in long pipe runs.
• Modular concept: the same body accepts different Danfoss clip-on coils, so AC or DC control voltages can be selected without changing the valve.
• Spare-part kits and coils are listed separately in the data sheet, which simplifies stocking for maintenance teams.

Sizing the valve for a flow duty

The Kv value of 11 m3/h is the water flow, in cubic metres per hour, that passes the fully open valve at a pressure drop of 1 bar. For other pressure drops, the flow of water is approximately Kv multiplied by the square root of the pressure drop in bar. This simple relation lets a designer check whether the G1 size is right: if the required flow would cause an excessive pressure loss, the next larger EV220B body may be needed, while a valve that is too large may not reach the minimum differential pressure for stable opening at low flow.

Remember that the valve must see at least 0.3 bar across it when open. On gravity-fed tanks, low-head rooftop systems or circuits where the downstream side quickly reaches upstream pressure, a direct-operated or assisted-lift valve may be a better choice than a servo-operated one.

Installation checklist

1. Flush the pipework before fitting the valve; weld spatter, PTFE tape and sand are the most common reasons for a servo valve that will not close.
2. Install with the flow in the direction of the arrow on the body.
3. Mount the coil upward where possible to keep dirt away from the armature tube.
4. Use suitable spanner flats on the body when tightening the G1 connections, and do not use the coil or armature tube as a lever.
5. Check that the coil voltage and frequency match the control supply before energising; a coil energised without being fitted to the armature tube can overheat.

Maintenance and troubleshooting

If the valve does not open, check coil voltage, the minimum differential pressure and whether the pilot orifice is blocked. If it does not close, look for dirt on the diaphragm seat, a blocked equalizing orifice or a damaged diaphragm. Replacing the diaphragm and armature with the matching spare-part kit usually restores tightness without removing the body from the line. Where hard water is used, periodic cleaning of the seat and the filter in front of the valve extends service life.

Applications in Oman and GCC conditions

Typical uses include automatic tank filling, irrigation and landscape networks, cooling tower make-up, water treatment skids, car wash equipment and process water in food plants. Desalinated and blended supplies in the region can vary in hardness and chloride content; where water is aggressive or stagnant in hot pipework, compare the DZR brass or stainless steel variants listed above. Coils installed outdoors should have a suitable enclosure rating and be shaded where possible from direct sun.

What to include in your RFQ

• Ordering number 032U7125 and quantity.
• Coil voltage, AC or DC, and required coil type or enclosure rating.
• Medium, maximum pressure, temperature and required flow.
• Need for spare-part kits or an alternative seal material.

Documents and quotation

The EV220B 15-50 data sheet is linked on this page. See the Danfoss EV220B 15-50 range page and the solenoid valves category. Seven Star LLC is an independent supplier in Muscat; confirm the medium, pressure, temperature and coil voltage with the exact order number 032U7125 before ordering.