Adjustable differential pressure overflow valve with scale (adjustment range 1–6 mWC)

Product overview

This adjustable differential pressure bypass valve ensures constant operating conditions in heating and cooling circuits with fluctuating flow rates. It returns excess flow proportionally to the number of closed consumers, thus limiting the differential pressure generated by the pump.

Technical specifications

The valve is designed for water and glycol solutions with a maximum glycol content of 30% and a temperature range of 0 to 110 °C. The maximum operating pressure is 10 bar; the adjustable intervention pressure is between 10 and 60 kPa (1–6 mWC).

materials

Housing and slide are made of brass EN 12165 CW617N, seals and O-rings made of EPDM as well as screw-in seals made of asbestos-free NBR. Handle made of ABS and spring made of stainless steel ensure durability and resistance to common operating media.

Connections

The valve is available with threaded connections according to ISO 228-1: 3/4” female thread for male thread with threaded fitting or 1 1/4” female thread for male thread with threaded fitting. The choice of connection depends on the installation location and the piping network of the system.

How it works

Adjusting the spring force via the handwheel changes the balance of forces on the valve and thus sets the engagement pressure. The valve only opens when the differential pressure exceeds the force of the contrast spring, thereby diverting a partial flow into the bypass and limiting the pressure in the affected section.

Operation of the plant

The bypass valve maintains the pump pressure close to the nominal value, even if the flow rate decreases due to the partial closing of 2-way valves. With a correctly sized valve, the pump is kept at its nominal operating point under all operating conditions, such as with fully closed thermostatic valves.

Installation instructions

The valve should be installed at a location where the differential pressure is representative of the section to be controlled and where an unobstructed bypass is ensured. Ensure proper sealing surfaces and matching threads, and install a pre-filter to keep foreign matter away from the valve.

Maintenance and operational safety

Regular visual inspection and, if necessary, cleaning of the valve area and seals will extend the service life. The spring and seals should be checked during extended periods of inactivity or after prolonged operation and replaced if worn.

Advantages and typical applications

The valve offers reliable pressure limitation, easy adjustment via scale, and a robust design for everyday use in heating, air conditioning, and industrial applications. Typical applications include systems with multiple thermostatic or motorized 2-way valves, return and distribution lines, and pump control circuits.

Technical data

• Maximum working pressure: 10 bar
• Medium temperature range: 0–110 °C
• Maximum glycol content: 30%
• Agents: Water, glycol solutions
• Setting: 10–60 kPa (1–6 m w.s.)
• Connections:
  • 3/4” female thread (ISO 228-1) for male thread with screw connection
  • or
  • 1 1/4” female thread (ISO 228-1) for male thread with screw connection