What the DU 1 Valve Does
The SKF Vogel DU 1 is a pressure-controlled hydraulic 4/2-way change-over valve for a dual-line central lubrication system. It directs pump pressure to one main line at a time and alternates automatically between the two lines. This site supplies an aftermarket replacement unit that matches the original valve interface and change-over function.
Official Specifications
- Maximum operating pressure: 350 bar.
- Change-over pressure adjustable: 140 to 350 bar; documented factory setting 170 bar on the pressure-controlled version.
- Main-line connections: G 1/2 female BSPP.
- Maximum flow: 14 dm3/h.
- Lubricant: grease up to NLGI 3; oil from about 60 mm2/s at 40 C per the detailed sheet.
- Temperature range: -20 to +80 C. Any mounting position.
- Electrical monitor rated up to 500 V, 25 to 60 Hz, with IP67 protection on the monitored version.
How the Change-Over Cycle Works
When the pump starts, line 1 is pressurized while line 2 returns to the reservoir. Pressure in the active line builds until it reaches the set change-over pressure; then the 4/2-way spool shifts. Line 2 is then pressurized and line 1 is relieved. This cycle repeats as long as the pump runs.
The DU 1 does not meter lubricant. The dual-line distributors along the mains perform that metering function. The valve only switches the pressurized main line at the correct pressure.
Variants: G, GK, and GKS
The official SKF Vogel designations include 3 common build styles.
- 617-28683-1 is DU1-G on a base plate.
- 617-28619-1 is DU1-GK with indicator pin.
- 617-28620-1 is DU1-GKS with indicator pin and limit switch.
All 3 share the same 4/2-way hydraulic spool and line connection size.
Matching a Dual-Line System
This valve fits a dual-line main distribution layout, not a single-line systems branch circuit. Check the main-line connection size, pressure range, mounting pattern, and monitor hardware before replacing an existing DU 1. No reliable Lincoln cross-reference exists in manufacturer documentation; do not treat DU 1 as a Lincoln number. If the system uses continuous grease or oil feed with two main lines, the DU 1 is the correct change-over component. Contact the quotation team for a match review.
Replacement Cautions
Depressurize both mains before removal because dual-line systems retain high pressure when stopped. Confirm that the replacement porting, pressure range, mounting, and monitoring hardware match the old unit exactly. A mismatch in change-over pressure can cause one main line to stay pressurized longer than intended.
Use only the official SKF Vogel model number from the nameplate, not a Lincoln cross-reference, when requesting a replacement. This site does not claim any Lincoln interchange for the DU 1.
Frequently Asked Questions
Is this a direct replacement for SKF Vogel DU 1?
It matches the original DU 1 interface and change-over behavior for dual-line systems. Confirm porting, pressure range, mounting, and monitor hardware before you install.
What lubricants can the DU 1 handle?
The valve handles grease up to NLGI 3 and oil from about 60 mm2/s at 40 C. Use a lubricant within these limits to keep the spool moving correctly.
Does the DU 1 meter grease or oil?
No, the DU 1 only changes the pressurized main line in a dual-line system. The dual-line distributors along the mains perform the actual metering.
What is the factory change-over pressure?
The pressure-controlled version has a documented factory setting of 170 bar. The change-over pressure is adjustable from 140 to 350 bar on this valve.
Can this valve be mounted in any position?
The valve can be mounted in any position without affecting change-over operation. Keep the electrical monitor version away from standing water despite its IP67 rating.
What does the limit switch do?
The limit switch on the GKS version confirms spool position for a controller. It is rated up to 500 V and 25 to 60 Hz on the monitored version.
Is there a Lincoln cross-reference for this valve?
No reliable Lincoln cross-reference exists in manufacturer documentation for the DU 1. Do not treat DU 1 as a Lincoln part number when ordering or replacing.
What connections does the DU 1 use?
Both main-line connections are G 1/2 female BSPP ports. The valve base plate style can change how those ports sit in a manifold.
Do I need to depressurize before removal?
Yes, depressurize both mains before you remove this valve. Dual-line systems retain high pressure when stopped, so a live line can release grease or oil.
Who builds and supports this valve?
IsoHiTech Lubrication Systems, founded in 2023, engineering since 2006, builds and supports every unit. Email inquiry@isohitech.com for specifications and a quotation.
To order this replacement valve from this site, contact the quotation team. SKF and Vogel are trademarks of their respective owners. This is an aftermarket change-over valve, not manufactured, sponsored, or endorsed by SKF. DU 1 and the 617-286xx part numbers are SKF Vogel designations shown for cross-reference identification only.
