Product Advantages

• Accurate Differential Pressure Control
• Controls Maximum Flow Through Pumps
• Circulating Loop Flow Control
• Completely Automatic Operation

The Cla-Val Model 250-01 Differential Pressure Relief Valve is a hydraulically operated, pilot-controlled, modulating valve. It is designed to maintain a constant pressure differential between any two pressure points in a system where the closing of the valve directly causes the differential pressure to increase. The valve tends to open on an increase in differential pressure and close on a decrease in differential pressure.

In operation, the valve is actuated by line pressure through a pilot control system sensing from two points across which a differential is to be maintained. Operation is completely automatic and pressure settings may be easily changed.

Schematic Diagram
Item Description
1.  100-01 Hytrol Main Valve
2.  X42N-2 Strainer & Needle Valve
3.  CDB-7 Differential Control

Optional Features
Item Description
B.  CK2 Isolation Valve
D.  Check Valves with Isolation Valve
F.  Remote Pilot Sensing (H.P.)
P.  X141 Pressure Gauge
S.  CV Speed Control (Opening)
V.  X101 Valve Position Indicator

The Model 250-01 Differential Pressure Relief Valve maintains a constant differential across centrifugal pump regardless of variable upstream pressures or downstream demand. By maintaining a constant differential pressure across a centrifugal pump operating at a known capacity, the maximum flow rate is controlled.

On a chilled water circulating loop system the 250-01 Differential Pressure Relief Valve is installed between loop supply and return lines to maintain a constant differential across the loop. The loop differential pressure remains constant regardless of the loop demand change thereby increasing cooling system efficiency.

Pressure Ratings (Recommended Maximum Pressure – psi)

Materials

CDB-7 Differential
Pilot Control

Adjustment Ranges (Differential
Pressure)
0 to 7 psi 50 to 150 psi
5 to 25 psi 65 to 180 psi
20 to 80 psi

Temperature Range
Water: to 180°F

Materials
Standard Pilot System Materials
Pilot Control: Low Lead Bronze
Trim: Stainless Steel Type 303
Rubber: Buna-N® Synthetic Rubber
Tubing & Fittings: Stainless Steel
Optional Pilot System Materials
Pilot Systems are available with
optional Aluminum, Stainless Steel or
Monel materials.

When Ordering, Specify:
1. Catalog No. 250-01
2. Valve Size
3. Pattern – Globe or Angle
4. Pressure Class
5. Threaded or Flanged
6. Trim Material
7. Adjustment Range
8. Desired Options
9. When Vertically Installed

EPDM Rubber Parts
Optional diaphragm, disc and o-ring fabricated
with EPDM synthetic rubber

Viton® Rubber Parts – suffix KB
Optional diaphragm, disc and o-ring fabricated
with Viton® synthetic rubber

Epoxy Coating – suffix KC
NSF/ANSI 61 Fusion Bonded Epoxy

Dura-Kleen® Stem – suffix KD
Fluted design prevents dissolved minerals buildup on the stem

LFS Trim
Designed to regulate precisely and smoothly at typical flow rates as well as lower than the industry standard of 1 fps, without decreasing the valve’s capacity