Direct-acting relief valve - pilot capacity
Two-port, pilot-stage, direct-acting relief cartridges are fully adjustable, normally closed pressure regulating valves. When the pressure at port 1 (inlet) is sufficient to overcome the spring force (valve setting), a flow path is opened from port 1 to port 2 (tank).
- Utilizes the Sun T-8A 2-port cavity making it the ideal choice to use in conjunction with Sun's main stage pilot or vent-to-operate cartridges. Separate pilot lines are eliminated and only one cavity needs to be machined to accommodate both the control and primary function. Note: All 2-position, 2-way pilot stage control cartridges utilize the same cavity and are physically interchangeable. Functionality is the only consideration.
- Note: The main stage valve should first be installed to the correct torque value followed by the T-8A pilot control section into the main stage valve to its required torque value.
- Ports 1 and 2 may be pressured to 5000 psi (350 bar).
- Hardened poppet and seat provide consistent operation, low leakage rates and superior wear characteristics.
- Backpressure at port 2 (outlet) is directly additive to the pressure setting at port 1 (inlet).
- Cartridges configured with EPDM seals are for use in systems with phosphate ester fluids. Exposure to petroleum based fluids, greases and lubricants will damage the seals.
- 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.
Cavity | T-8A |
Series | P |
Capacity | 2.5 gpm10 L/min. |
Maximum Operating Pressure | 5000 psi350 bar |
Factory Pressure Settings Established at | 2 in³/min.30 cc/min. |
Maximum Valve Leakage at 110 SUS (24 cSt) | 15 drops/min.1 cc/min. |
Response Time - Typical | 2 ms2 ms |
Valve Hex Size | 7/8 in.22,2 mm |
Valve Installation Torque | 20 - 25 lbf ft27 - 33 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 |
Seal kit - Cartridge | Buna: 990608007 |
Seal kit - Cartridge | EPDM: 990608014 |
Seal kit - Cartridge | Polyurethane: 990008002 |
Seal kit - Cartridge | Viton: 990608006 |
Pressure setting tolerances are listed in our Performance Data page. A link to this page can also be found in the Additional Resources tab of the applicable product page.
There are exactly 250 Sun drops in a cubic inch or 15 in a cc.
Maybe not. We build in a good amount of overlap in the kick-down reliefs to prevent false tripping. This means they are not as fast as our standard pilot-operated reliefs. A direct-acting relief valve set just above the kick-down relief valve would be good insurance.
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.
One graphic example is on a portable grain auger for silos. When the farmer gets caught in the auger the kick-down relief trips and allows him to escape.
- For Series 1 cartridges configured with an O control (panel mount handknob), a .75 in. (19 mm) diameter hole is required in the panel.
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- Get the relief you need. Adjustable. Ventable. Blockable. FLeX-ible.
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