Graco Piston Valve, 190es, 395 ST, 490 ST, UltraMax II 695 (218197)

Graco Piston Valve, 190es, 395 ST, 490 ST, UltraMax II 695 (218197)

The piston valve sits in the fluid section on top of the ball cage with the displacement rod, nut, and packings. This will often sit inside of the intake housing or on top of the packing nut.

The job of the piston valve (also called an outlet valve) is to allow material to flow one way through the fluid section only.  When you release the trigger and let the sprayer build to maximum pressure, if the piston slowly start to move upwards, that is a sign of a worn valve, or a sign that you have debris in the valve that is preventing the ball from seating.  

Replacement part for use with these airless paint sprayers:

• 233815 - 190ES (including stand and HiBoy)
• 226820 - 380 EM
• 231001 - 380 EM Bare
• 231390 - 390 EM
• 231580 - 395 Duron
• 231575 - 395 ST
• 231400 - 400 Ultra
• 231547 - 450 ST
• 231581 - 455 ST
• 220679 - 490 EM Series
• 231208 - 490 ST
• 231357 - 490 ST HiBoy
• 232654 - 495 Duron HiBoy and LoBoy
• 231584 - 495 ST
• 231586 - 495 ST HiBoy
• 820105 - 500 Ultimate
• 231032 - 500 Ultra Series
• 820208 - Ultimate 600 Plus
• Ultra Max II 695 Series
• GM 3000 Series
• 234187 - DT
• 820001 - Nova (Old Model)
• 824012 - NOVA SPX
• 223636 - Pro 301 Series
• 235039 - Fultronic 500
• 223637 - Pro 501
• 826031 - SP
• 234127 - ST
• 820002 - Super Nova Series
• 232650 - LineLazer 3400