GRACO 25R491 – Medium Pressure Fluid Back Pressure Regulator, 3000 Max psi, 5 gpm Max flow rate,

GRACO 25R491 – Medium Pressure Fluid Back Pressure Regulator, 3000 Max psi, 5 gpm Max flow rate, SST, Mechanical w/ locking nut, 3/8″ NPT

GRACO 25R491 mechanical back pressure regulator maintains upstream fluid pressure regardless of flow demand, allowing operators to trigger guns, valves and other flow controls without affecting system pressure. This medium pressure BPR provides consistent fluid control crucial for quality finishing processes, with easy installation and spring operation that doesn’t require compressed air.

Improve fluid control without having to add a compressed air line with this spring-operated back pressure regulator (BPR).

Additional Specifications

Flow Rate: 0 – 5 gpm

Length: 6.25 in. (159 mm)

Thread: 3/8 in. NPT

Diameter B: 2.38 in. (60 mm)

Max Fluid Inlet Pressure: 3000 PSI (20.7 MPa, 207 bar)

Max Air Working Pressure: ——

Pressure Category: medium pressure

Flow Category: low flow

Mechanism: mechanical with locking nut

Flow Type: Lower Flow

Operation: Mechanical

Specifications

Compatible Material	Waterborne, Solventborne
Gauge Port Size (in)	1/4
Gauge Port Type	NPT
Inlet Size (in)	0.375
Inlet Thread Type	NPT
Maximum Air Inlet Pressure (psi)	100
Maximum Flow Rate (GPM)	5
Maximum Operating Temperature (°F)	122
Maximum Regulated Pressure (psi)	3000
Maximum Viscosity (cP)	250
Maximum Working Pressure (psi)	3000
Minimum Operating Temperature (°F)	32
Minimum Regulated Pressure (psi)	250
Outlet Size (in)	0.375
Outlet Thread Type	NPT
Type	Back Pressure Regulator
Wetted Material	Stainless Steel, Tungsten Carbide, PTFE, Acetal Homopolymer

Features

Maintains upstream fluid pressure regardless of flow demand

Spring operation – no compressed air required

Easy installation

Better resolution for accurate pressure adjustment

Wet parts include stainless steel, tungsten carbide, PTFE, acetal homopolymer

Applications

Finishing process control

Quality control for finishing processes

Fluid control systems where compressed air line addition is not desired

Related Parts

25T478 – Medium Pressure Fluid Back Pressure Regulator, 1000 Max psi, 5 gpm Max flow rate, SST, Pneumatic, 3/8″ NPT

25T477 – Medium Pressure Fluid Back Pressure Regulator, 2000 Max psi, 5 gpm Max flow rate, SST, Pneumatic, 3000 PSI, 3/8″ NPT

25R490 – Medium Pressure Fluid Back Pressure Regulator, 3000 Max psi, 5 gpm Max flow rate, SST, Pneumatic, 3/8″ NPT

Kit Contents

19C099 – CYLINDER, VALVE

19Y873 – HOUSING, BPR, MEDIUM PRESS

238932 – PISTON, VALVE

238933 – SEAT, VALVE

113751 – RING, RETAINING, INTERNAL

166986 – SPRING, HELICAL

189817 – GASKET

111796 – SEAL, U-CUP

171885 – WASHER

166985 – PACKING, O-RING

101748 – PLUG, PIPE SST

166988 – GUIDE, SPRING

20A104 – ADJUSTER, SCREW, BPR, SPRING

101970 – PLUG, PIPE, HDLS, optional if gauge is not used

20A105 – NUT, LOCK, REGULATOR, BPR

Installation and operation instructions available in manual 3A7681. Part of GRACO’s medium pressure BPR family which includes three pneumatic models (1000, 2000, 3000 PSI) and one mechanical model (3000 PSI). Part of back pressure regulator family with different flow and pressure configurations. Has CE and ATEX approvals (Ex h IIB T6 Gb, 0°C to 50°C). Type of Protection is constructional safety ‘c.’ Assembly includes torque specifications: 175-200 in-lbs (20-23 Nm) for some components and 60-70 ft-lbs (81-95 Nm) for others. Uses NLGI Grade 2 grease (Chevron SRI), Molykote G-N paste for threads, and thread sealant. Some parts are included in Repair Kit 239000 and Repair Kit 17M564.

Reference Manuals

345174 (Page 2) Medium Pressure BPRs

3A7681 (Page 2) Medium Pressure Back Pressure Regulators