Technical data

MD2 Valve Models
2 312185S
Contents
MD2 Valve Models . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Component Identification . . . . . . . . . . . . . . . . . . . . 5
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Technical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Graco Standard Warranty . . . . . . . . . . . . . . . . . . . 30
Graco Information . . . . . . . . . . . . . . . . . . . . . . . . . 30
MD2 Valve Models
Model Selection
The following table provides a summary of the MD2 dispense valves that are described in this manual.
MD2 Valves
Part No.
Maximum Working Pressure
psi (MPa, bar) Description
255179
3000 psi (20.7 MPa, 207 bar
1:1 Soft seat, adjustable snuff-back
255180 1:1 Hard seat, non-adjustable snuff-back
255181 Wide ratio, soft seat, adjustable snuff-back
255182 Wide ratio, hard seat, non-adjustable snuff-back
255183 2000 psi (13.8 MPa, 138 bar) Cold spray/joint fill valve
MD2 Valve Handles
255206 120 psig (0.84 MPa, 8.4 bar) Air trigger
255208 3A @ 28 VDC Electric air actuated
255249 0.5 @ 28 VDC Electric actuated lever
Type Description
Hand held valves with
internal air trigger
The internal air trigger controls the air piston that operates the MD2 valve. A pilot port
can be used to control a pump motor.
Hand held valve with
electric switch
The switch signals the customer’s controller to open and close the ports on the MD2
valve using a remote 4-way air control valve which is not included.
Wide ratio valves The wide ratio MD2 valve has a center injection tip. This feature is helpful with wider
ratio applications, specifically when the low volume material is a much lower viscosity
than the high volume material. Frequent cleaning intervals may be required to maintain
the tip.
Hard seats Carbide seats and hardened needles are good for abrasive materials and stall against
pressure applications.
Soft seats UHMWPE seals are good for precise snuff-back control.