2-way, pilot-to-shift directional valve with drain to port 4 - normally open

Capacity: .5 gpm2 L/min. | Cavity: T-21A
DRAY : 2-way, pilot-to-shift directional valve with drain to port 4 - normally open
Technical Features [ + ]

The normally-open, direct-acting 2-way directional cartridge with external drain is a pilot unloading valve used to sense pressure in one circuit to switch or unload a valve in a different circuit. When pressure at port 1 exceeds the setting of the valve, the spool shifts to block port 2 from port 3.

  • The pilot area (port 1) and the spring chamber drain (port 4) are positively sealed.
  • There is spool leakage between the work ports (ports 2 and 3)of less than 20 drops/min (1,4 cc/min).
  • The valve is designed to not modulate and is the equivalent of a hydraulic pressure switch.
  • Incorporates the Sun floating style construction to minimize the possibility of internal parts binding due to excessive installation torque and/or cavity/cartridge machining variations.
Technical Data [ + ]
Note: Data may vary by configuration. See CONFIGURATION section.
Cavity T-21A
Series 1
Capacity .5 gpm2 L/min.
Maximum Operating Pressure 5000 psi350 bar
Maximum Valve Leakage at Reseat 20 drops/min.20 drops/min.
Reseat >85% of setting>85% of setting
Valve Hex Size 7/8 in.22,2 mm
Valve Installation Torque 30 - 35 lbf ft41 - 47 Nm
Adjustment Screw Internal Hex Size 5/32 in.4 mm
Locknut Hex Size 9/16 in.15 mm
Locknut Torque 80 - 90 lbf in.9 - 10 Nm
Model Weight .30 lb0,15 kg
Seal kit - Cartridge Buna: 990021007
Seal kit - Cartridge Polyurethane: 990021002
Seal kit - Cartridge Viton: 990021006
Performance Curves [ + ]
FAQs [ + ]

There are exactly 250 Sun drops in a cubic inch or 15 in a cc.

Direct-acting valves are used to prevent over pressure, and pilot-operated valves are used to regulate pressure. If you are unsure, use a direct-acting valve. Sun's direct acting valves are very fast, dirt tolerant, stable, and robust. Sun's pilot-operated valves are moderately fast, they have a low pressure rise vs. flow curve, and they are easy to adjust.

Only external seals are serviceable.  Sun offers replacement seal kits for all cartridge models. The applicable kit part number can be found in the product page's Technical Data table or by using our Cartridge Seal Kit search function located under Accessories. Please note: Converting the external seals from one material to another does not ensure fluid compatibility with that material due to the existence of internal seals within the cartridge.

DP**s and DR**s are from the reducer/reliever family and are very capable of modulating. They are not bistable.

In many circuits the directional cartridge is set to shift at a low pressure no matter how high the pilot pressure goes. If you use a DP__ , the pilot flow increases to significant amounts. A DR__ however will only consume a small amount of flow. A DP__ is useful when you want to block or open the pilot flow to shift the valve.

Additional Resources [ + ]