Assembly Build Process

Sun's Assembly Build Process allows you to configure a cartridge and manifold, or main stage and pilot stage cartridge, and build a digital assembly in three dimensional space. The resulting output of this process is the assembly product page, including configuration-specific images, symbols, product information and CAD files for download.

The Assembly Build Process can be accessed from either a cartridge or manifold product page. Only valid choices are allowed.

From a manifold page, you must first choose your cartridge function. Once you choose your function, click on the BUILD ASSEMBLY button below the WHERE TO BUY BUTTON. Once clicked, you will be presented with valid cartridges for your manifold. Select the cartridge of your choice and follow the instructions at the top of the page. If your particular combination has been generated before, the resulting assembly page will be available immediately. If not, you will be asked to enter your email address. Once the page is complete, an email will be sent to you including a link to the assembly product page.

From a cartridge product page, click on BUILD ASSEMBLY and you will be presented with a listing of compatible manifolds. In the case of main stage and pilot stage cartridges, you can either build a cartridge to cartridge assembly or a cartridge to manifold assembly. Once your choice has been made, follow the instructions at the top of the page. If your particular combination has been generated before, the resulting assembly page will be available immediately. If not, you will be asked to enter your email address. Once the page is complete, an email will be sent to you including a link to the assembly product page.

Please note that the Assembly Build Process is an automated process. It can be utilized at any time. Pages are generated typically within minutes but delays can occasionally be expected. In the event of a delay, a team at Sun will work to resolve the issue to ensure you receive your information as quickly as possible.

20%, accumulator sense, pump unload valve with check - pilot capacity

Capacity: 15 gpm60 L/min. | Cavity: T-21A

Expand All

Technical Features [ + ]

The accumulator sense, pump unload pilot valve is used to sense pressure in an accumulator at port 2 of the valve and when the pressure at port 2 reaches the valve setting, port 3 connects to port 4 to vent a relief valve and unload the pump. This valve has a 20% ratio between unload setting and reset; when pressure at port 2 falls below 80% of the valve setting, port 3 is blocked from port 4 and the pump will come back online to recharge the accumulator.

The integral free-flow check valve is suitable for pump flows up to 15 gpm (60 L/min). For higher capacity pumps, another version of accumulator sense, pump unload cartridge, QPAB, which requires a separate check cartridge is available.

The pressure differential between unload and reset will be within +3/-2% of the stated ratio of the valve.
The accumulator sensing area is positively sealed.
The spool design of this valve allows it to maintain a fixed differential ratio because the areas are created by diameters on the spool that will not wear or change with use.
Minimum clearances between the spool and sleeve and a seal on the pilot piston diameter significantly reduce the potential for silting.
When applying this cartridge, a separate drain line is required to prevent erratic operation caused by tank line pressure fluctuations.
NOTE: Careful consideration should be given when selecting an adjustment range. System pressure drops and flows tend to affect the operation of unloading valves. Low operating pressures combined with low differentials result in a very narrow band between unload and reset, requiring precise system design. High flow rates typically mean high pressure drops, which subtract from the differential the valve has to work with.
Sun has designed a variety of standard accumulator/pump unload assemblies with a variety of features. These assemblies can be found on our website under SOLUTIONS: ACCUMLATOR SENSE, PUMP UNLOAD.
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	15 gpm60 L/min.
Maximum Operating Pressure	5000 psi350 bar
Check Cracking Pressure	4 psi0,3 bar
Pressure Drop, Port 1 to Port 2	100 psi@15 gpm7 bar@60 L/min.
Pilot Flow Capacity	46 in³/min.0,75 L/min.
Adjustment - No. of CW Turns from Min. to Max. setting	55
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	.35 lb0,15 kg
Seal kit - Cartridge	Buna: 990021007
Seal kit - Cartridge	Polyurethane: 990021002
Seal kit - Cartridge	Viton: 990021006

Performance Curves [ + ]

Performance Curve for QCDB: 20%, accumulator sense, pump unload valve with check - pilot capacity

FAQs [ + ]

How big is a drop of hydraulic oil?

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

I need to charge an accumulator. What do I need to know?

See our Highlight on Accumulator Sense, Pump Unload Valves for detailed information.

What parts of the Sun cartridge valve are field serviceable?

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.

Additional Resources [ + ]

Highlights

Technical Tips