DR45 Reversing Valve — Dual-Line Change-Over
The DR45 pressure / reversing valve is an automatic change-over valve for dual-line centralized lubrication. When the pump pressurizes supply Line A, grease or oil flows through metering blocks on the A-side cycle; at set pressure the valve switches flow to Line B and vents Line A—then reverses again on the next pump stroke. No manual line swapping is required.
Adjustable pressure range: approximately 500–3500 psi (34–241 bar); factory setting typically 1500 psi. Lubricants: oil from SAE 10 through system oil grades and grease to NLGI #2. Body: steel with zinc yellow chromate finish. Works in return and non-return dual-line layouts.
Install between BS-B dual-line pump header and main lines; downstream blocks include ZVB, VSG, VSL, and DW. Compare alternate valve: SA-V reverse valve. Architecture: dual-line lubrication systems.
- Parameter
DR45 Connection & Materials
| Item | Specification |
|---|---|
| Type | Automatic reversing valve (dual-line) |
| Pressure range | 500–3500 psi (~34–241 bar), adjustable |
| Factory setpoint | Typically 1500 psi |
| Inlet thread | 1/4 NPSF |
| Outlet thread | 3/8 NPSF |
| Relief thread | 1/2 NPSF (alt. 1/8 NPSF) |
| Material | Steel, zinc yellow chromate |
| Lubricant | Oil SAE 10+ ; grease to NLGI #2 |
How Reversing Works
An internal hydraulic pressure sensor detects when the active line reaches the valve setting. The spool shifts, directing pump flow to the opposite main line and connecting the spent line to vent or return. Each full A→B→A sequence allows dual-line metering blocks to deliver one dose per point per half-cycle.
Pressure Adjustment
Adjust while system is pressurized (follow lockout rules):
- Clockwise — increase switching pressure
- Counter-clockwise — decrease switching pressure
Do not unscrew adjustment screw too far—internal parts can unload and damage the valve. Set switching pressure high enough to fully shift blocks on the longest line, but below pump relief/overload.
DR45 vs SA-V Reverse Valve
| Valve | Typical use |
|---|---|
| DR45 (this page) | Adjustable 500–3500 psi; common on BS-B dual-line grease plants |
| SA-V | Alternate reversing family—confirm interchange with system designer |
Neither valve belongs on single-line progressive systems (DJF1000, M2500)—those use one supply line only.
Applications
- Steel, cement, mining — dual-line grease on long conveyors and kilns
- Heavy presses — many points on alternating line pressure
- Oil dual-line — circulating oil systems within DR45 lubricant range
Where DR45 Mounts in the Plant
Mount the DR45 at the pump header or central manifold—close to the BS-B pump outlet to minimize lag in switching. Main lines A and B run parallel along the machine; metering blocks tee off each line. Keep hose lengths and bends within pump catalog limits so switching pressure remains repeatable.
Commissioning Checklist
- Set factory 1500 psi as starting point; run pump and verify valve reverses each cycle.
- Confirm grease at farthest block on both A and B half-cycles.
- Adjust switching pressure if reversal occurs too early (starving lines) or too late (overloads pump).
- Tie cycle counter or pressure switch to PLC for missed-reversal alarm.
- Document set pressure on lubrication plate beside pump ID.
Troubleshooting
| Issue | Cause | Fix |
|---|---|---|
| No reversal | Set pressure above pump capability; stuck spool | Lower setting; clean/replace valve |
| Leak at relief | Seat dirty; pressure too close to setpoint | Service seat; increase margin |
| Rapid cycling | Set pressure too low; line leak on active side | Raise setting; find leak |
| One line never gets grease | Blocked downstream; wrong port plumbing | Clear block; verify A/B labeling |
Before you buy: read our grease fitting types guide.
Adjustable 500–3500 psi (34–241 bar); factory default typically 1500 psi.
Under pressure, turn clockwise to increase, counter-clockwise to decrease. Do not unscrew excessively.
SAE 10 oil through system oils and grease to NLGI #2.
Inlet 1/4 NPSF, outlet 3/8 NPSF, relief 1/2 NPSF (alternate relief 1/8 NPSF).
Suitable for both dual-line return and non-return designs—confirm vent path on P&ID.
Often set pressure too close to operating pressure, dirty seats, or worn internals—service per manual.
Both are reversing valves—choose per plant standard, port layout, and pressure class; see SA-V page.
No. Progressive systems use one line (DJF1000, FS pump)—no A/B switching.