High Pressure in a Centralized Lubrication System: Causes and Troubleshooting

High pressure in a centralized lubrication system does not simply mean that the pump is powerful. It usually means that lubricant cannot complete its designed route through the pump, divider, injector, pipeline and lubrication point.

For a maintenance engineer, the important question is not only how high the pressure has reached. The important question is which component has stopped the lubrication cycle.

At INALUBE, we identify the pressure fault by using the functions of each component. The progressive divider shows whether the sequence has stopped. The pressure switch confirms whether the single-line system has reached the required pressure. The directional valve controls pressure transfer in a dual-line system. Filters protect the pump and metering elements, while the controller records the lubrication interval and alarm condition.

High pressure is therefore diagnosed through the complete system configuration rather than by replacing the pump without checking the distribution components.

How INALUBE Defines a High-Pressure Fault

During a normal lubrication cycle, the pump supplies oil or grease, the divider or injector meters the lubricant, and the system releases pressure after the required delivery is completed.

We treat the pressure as abnormal when one of the following conditions occurs:

• The pressure reaches the safety setting and remains there.
• The pressure rises during every cycle but never releases completely.
• The controller reports a pressure alarm before the divider or injector completes its movement.
• One branch stops receiving lubricant while other branches continue working.
• The pressure increases after a lubricant, hose, divider or valve has been replaced.

These conditions identify different component problems. A progressive divider blockage, a single-line pressure-release fault and a dual-line directional-valve fault cannot be solved with the same pump adjustment.

1. Progressive Divider Blockage: How the PFB Identifies the Stopped Sequence

A progressive divider distributes lubricant through a sequence of piston movements. Each piston movement controls the next part of the distribution cycle. When one outlet or branch is blocked, the sequence stops at that position and the pump continues building pressure.

This is why one blocked lubrication point can create high pressure for the entire progressive circuit.

Our PFB progressive divider is available with three monitoring configurations:

• Standard PFB: without an additional blockage monitor.
• PFB-M: with a visual indicator for checking piston movement.
• PFB-E: with a piston detector for electrical monitoring.

The PFB series is also available with different outlet quantities, including configurations with 16, 18, 20 and 22 outlets. We select the outlet quantity according to the number of lubrication points and the branch arrangement.

When a system with a PFB-M divider shows high pressure, we inspect the visual indicator. If the indicator stops at one position, the restriction is located at that divider section or downstream branch.

When the system uses a PFB-E divider, the piston detector provides an electrical signal to the controller. The controller can then identify that the divider has stopped instead of allowing the pump to continue operating against a blocked outlet.

For this type of system, our configuration is:

• LUBElite™ Progressive Lubrication Pump
• PFB, PFM, PFMS or PFG progressive divider
• PFB-M visual monitoring or PFB-E piston detection where alarm feedback is required
• SC100 controller or an integrated pump controller
• Correctly sized high-pressure hose and fittings

We do not solve a stopped PFB sequence by increasing the pump pressure. We locate the blocked outlet, branch hose, fitting or bearing and restore the sequence.

See our progressive lubrication divider solutions for different outlet and monitoring configurations.

2. Single-Line System Pressure: How the Pressure Switch and Injector Work Together

A single-line lubrication system requires two distinct stages. The pump first pressurizes the main line. The injector then meters the required lubricant. After delivery, the system must release pressure so the injector can reset for the next cycle.

High pressure occurs when the injector does not discharge, the pressure-release path remains closed, or the branch connected to the injector has excessive resistance.

SFM-1: Controlling the Lubricant Quantity at Each Point

The SFM-1 single-line injector is available with 2, 3, 4, 5 or 6 outlets. Its listed displacement range is 0.015–0.3 cm³ per outlet.

This function is directly related to high-pressure troubleshooting. If the required lubricant quantity is too high for the selected metering arrangement, the system remains under pressure for longer. If one SFM-1 outlet is blocked, the pressure rises while the other outlets may continue to operate.

We therefore check the SFM-1 outlet connected to the affected bearing, the outlet fitting and the branch hose before changing the pump setting.

GOP Oil Single-Line Pump: Pressure Confirmation for Oil Systems

For oil lubrication, we use the GOP Oil Single Line Lubrication Pump. The GOP10MCPA23 configuration shown on the product page has a 10 L metal tank, a controller, a pressure switch and a pump delivery of 160 cm³ per stroke.

The pressure switch is not a decorative accessory. It confirms whether the oil circuit has reached the required pressure during the lubrication cycle. When the pressure is reached too quickly, the branch may be blocked. When the pressure cannot be reached, the pump inlet, oil level, line leakage or injector requires inspection.

FGP: Fluid Grease Supply Without Using a Standard-Grease Pump

For fluid grease, we use the FGP Fluid Grease Single Line Lubrication Pump. Fluid grease does not have the same flow behavior as standard grease, so the pump and metering system must be selected for that lubricant.

Using the wrong pump configuration creates unstable filling, inconsistent metering and abnormal pressure behavior. We select the FGP configuration together with the correct single-line injectors and pressure-release components.

HeavyXtreme™: High-Volume Grease Supply

HeavyXtreme™ is designed for high-volume grease delivery. The HXP55EHD configuration listed on the product page has a 55 kg tank, a displacement of 444 cm³/min and an electric level sensor.

When a high-volume grease system shows high pressure, we separate two different problems:

• If the pump output is high but the divider or injector is restricted, the pressure rises because the distribution circuit cannot accept the delivered grease.
• If the pump cannot feed grease consistently, the suction path, grease condition and inlet components require inspection.

HeavyXtreme™ solves the supply capacity problem. It does not replace the need for correctly sized injectors, hoses and pressure-release valves.

3. Dual-Line High Pressure: How DuoEX™ Controls Pressure Transfer

A dual-line system uses two main lines alternately. One line is pressurized while the other line is released. The system then changes direction and repeats the cycle.

The most important function in a dual-line system is therefore not only pump pressure. The system must complete pressure transfer and pressure release in the correct sequence.

DuoEX™ includes an integrated directional valve. The listed DEP5410LXVA38 configuration has a 100 L tank, low-level monitoring, a 540 cm³/min pump element, a G 3/4 pump outlet and a G 3/4 return outlet. The DEP5406LXVA38 configuration uses a 60 L tank with the same pump element and integrated directional-valve arrangement.

These functions directly address several high-pressure faults:

• Integrated directional valve: controls the changeover between the two main lines.
• Return outlet: provides the return path required for pressure release.
• Low-level monitoring: prevents the pump from operating without sufficient lubricant supply.
• 540 cm³/min pump element: provides the required delivery for large dual-line circuits.

When one dual-line circuit remains at high pressure, we inspect the integrated directional valve, the return outlet, the active and inactive main lines, and the connected dual-line divider.

If the system uses a separate directional-valve arrangement, we use the XV-250 Directional Valve. The SV Safety Valve is used for system pressure protection. We do not increase the pump setting to compensate for a valve that has failed to change position or a return path that has been blocked.

We match DuoEX™ or LUBElite™ Dual-Line Lubrication Pump with TWINflex™ TFU, TWINflex™ TFB, DFB or DFM dual-line dividers according to the circuit layout.

Our dual-line divider range provides the metering and distribution function after the pump and directional valve complete the pressure cycle.

4. How the TWINflex™ TFU Prevents Uneven Metering

The TWINflex™ TFU dual-line divider includes a metering valve and metering marks. These functions allow the installer to identify the metering position and maintain consistent adjustment across different outlets.

When one outlet delivers less lubricant than the others, we inspect the TFU metering valve and the associated outlet. A partially restricted metering valve increases upstream resistance and creates a pressure difference between branches.

We check the TFU together with the two-line pressure sequence. The divider cannot operate correctly if the main-line pressure does not transfer from one side to the other.

5. How Filters Prevent Pressure Increase Caused by Contamination

Contamination blocks pump elements, injectors and divider passages. The restriction develops inside the component, so the external pipeline may look normal while pressure continues to rise.

INALUBE provides separate filter configurations for different lubricants:

• FO Oil Filter: for oil lubrication circuits.
• FL Grease Filter: for grease systems.
• FC Grease Filter: for grease filtration before the metering circuit.
• FR Grease Filter: for grease protection in the lubrication system.

We select the filter according to the lubricant and install it before contamination reaches the pump element or metering divider. When high pressure appears after contaminated lubricant has entered the system, we inspect the filter first and then check the pump element, divider and injector.

6. How Hoses and Fittings Create High Pressure

A lubrication pipeline is part of the pressure system. A crushed hose, incorrect fitting passage, excessive bending or unsuitable tube creates resistance before the lubricant reaches the bearing.

INALUBE supplies plastic tube, steel tube, fittings and high-pressure hose. We select the pipe material and hose according to the installation position, pressure requirement, vibration and movement of the machine.

For troubleshooting, we isolate the hose downstream of the divider. If pressure falls after the hose is disconnected, the blockage is located in the hose, fitting or connected bearing. If pressure remains high, we continue checking the divider and upstream components.

7. How the LUBElite™ Progressive Pump Controls the Supply Cycle

The LUBElite™ Progressive Lubrication Pump is available with different tank capacities, including 2 L, 4 L, 6 L, 8 L and 10 L configurations. The series also includes low-level monitoring options and controllers with hour- or minute-based interval settings.

These functions relate directly to high-pressure control:

• Low-level monitoring: prevents the pump from running without sufficient lubricant.
• Hour- or minute-based control: sets the lubrication interval according to the machine duty cycle.
• Multiple tank sizes: match the reservoir to lubricant consumption and maintenance intervals.
• Multiple pump mounting ports: support different divider and pipeline arrangements.

If the lubrication interval is too short for the machine, the system supplies grease before the previous cycle has fully completed. If the divider or bearing already has high resistance, repeated cycles increase the pressure alarm frequency.

We therefore set the controller interval after confirming lubricant quantity, divider capacity and machine operating time. The controller is used to control the lubrication cycle, not to mask a blocked branch.

How INALUBE Matches Products to a High-Pressure Problem

Our Troubleshooting Procedure

Step 1: Stop the Pump and Release Pressure

We stop the automatic lubrication cycle and release pressure through the designated service point. We never loosen an ordinary fitting on a pressurized grease line.

Step 2: Check the Pressure Signal

We compare the pressure switch or sensor with a calibrated gauge. On GOP systems, we check the pressure-switch signal. On systems using SC100 or an integrated controller, we check the alarm history and interval settings.

Step 3: Identify the Distribution Component

We determine whether the machine uses a progressive divider, single-line injector or dual-line divider. This identifies the correct internal movement to inspect.

Step 4: Inspect the Relevant Product Function

For PFB systems, we inspect the visual indicator or piston detector. For SFM-1 systems, we inspect the metering outlet and reset action. For DuoEX™ systems, we inspect the integrated directional valve and return outlet.

Step 5: Isolate the Branch

We disconnect one branch at a time. A pressure drop identifies the blocked hose, fitting, injector, divider outlet or bearing connection.

Step 6: Check Filter and Lubricant Condition

We inspect the correct filter type, lubricant contamination, grease consistency and pump suction path. A contaminated filter or hardened lubricant is removed before the system is recommissioned.

Step 7: Restore the Correct Cycle

After the fault is removed, we verify pressure release, divider movement, injector metering and lubricant delivery. We then set the controller interval according to the actual lubricant consumption and machine duty cycle.

Why We Do Not Solve High Pressure by Raising the Pump Setting

Raising the pressure setting forces lubricant against the restriction. It does not restore the blocked PFB sequence, reset a stuck SFM-1 injector or change the position of a failed directional valve.

Our method is to use the function of the installed product to locate the fault:

• The divider monitor identifies a stopped progressive sequence.
• The pressure switch confirms the single-line pressure condition.
• The directional valve controls dual-line pressure transfer.
• The filter protects the pump and metering components.
• The controller controls the lubrication interval.
• The safety valve protects the circuit against excessive pressure.

This is how we solve the cause of high pressure instead of only suppressing the alarm.

INALUBE Order & Project Support

INALUBE supplies LUBElite™ progressive pumps, LUBElite™ single-line pumps, GOP oil pumps, FGP fluid-grease pumps, HeavyXtreme™, DuoEX™, LUBElite™ dual-line pumps, progressive dividers, single-line injectors, dual-line dividers, filters, valves, controllers and high-pressure piping components.

For technical evaluation, send us the current pump model, divider or injector model, lubricant type, pressure reading, alarm timing, line layout and photographs of the installation.

We will identify the component responsible for the pressure increase and recommend the correct pump, divider, injector, valve, filter or pipeline configuration for your application.

Please contact INALUBE for Order & Project Support.

Frequently Asked Questions

Which INALUBE product detects a blocked progressive divider sequence?

The PFB progressive divider is available with a visual indicator or piston detector. The visual indicator supports local inspection, while the piston detector provides an electrical monitoring signal.

Which INALUBE product confirms pressure in an oil lubrication system?

The GOP Oil Single Line Lubrication Pump configuration includes a pressure switch. The GOP10MCPA23 configuration has a 160 cm³/stroke pump delivery and a 10 L metal tank.

Which INALUBE product controls direction change in a dual-line system?

DuoEX™ includes an integrated directional valve. The system also provides pump and return outlets for the dual-line pressure cycle.

What causes high pressure in an SFM-1 single-line injector system?

A blocked metering outlet, incorrect displacement, a restricted branch hose, a bearing connection with excessive resistance or incomplete pressure release causes the pressure to remain high.

Which filter should be used in a centralized lubrication system?

We select FO for oil, and FL, FC or FR for grease according to the lubricant and the position of the filter in the system.