Troubleshooting & maintenance

Most lubrication faults announce themselves the same way: a bearing runs hot, a point comes up dry, or the pump cycles and nothing arrives. This page walks the checks in the order that finds the cause fastest — starting at the pump, ending at the sensors — and explains the two failure modes that account for most stopped systems. If the system is newly installed, start with commissioning instead — a large share of “faults” on a new install are air that was never purged.

Start here

A four-step inspection

Before replacing anything, walk the system in this order. Each step narrows where the fault can be, so by step four you are testing one component rather than guessing.

Step 1

Is the pump running normally?

Take a general view of how the pump is behaving before you touch it. Check the oil injection speed, the operating environment and the lubrication cycle. Confirm the run indicator is showing normally, and that the linkage between the external supply, the equipment supply, the pressure switch and the oil supply switch is intact. Check whether the lubricant in use has become contaminated.

Step 2

Trace the system for leaks

Look around the whole system first — that alone usually gives you the direction of a leak. Then examine the pump body itself: it carries many parts and works hard, so leaks here come from seals that have worn or been damaged, or from fasteners that are not properly seated. Then follow the oil circuit out to the distributors and points.

Step 3

Check each distributor outlet

The distributor is both the most common source of leakage in a lubrication system and the easiest place to see what is happening. Checking delivery at the distributor and at each lubrication point localises the fault to a single outlet or line, rather than leaving it somewhere in the system.

Step 4

Test the sensors with a multimeter

Grease is difficult to inspect visually once it is inside the system. Use a multimeter to check each sensor in turn — pressure switch, level switch, cycle indicator — and eliminate them one by one, so a sensor that is simply not responding is not mistaken for a lubrication fault.

Two failure modes worth understanding

Why systems stop

Between them, a blocked progressive outlet and air trapped in the pump chamber explain most systems that are running but not delivering.

A blocked outlet stops the whole cycle

A progressive distributor feeds its outlets in sequence. Each piston has to complete its stroke before the next one can move, so the outlets are mechanically interlocked rather than independent.

That is the architecture's great advantage and its characteristic fault. The advantage is that a blockage cannot hide: if one outlet cannot discharge, the piston behind it cannot move, the cycle halts, and pressure rises — which is exactly what the blockage alarm output is there to detect. The consequence is that one blocked point takes every other point on that distributor down with it, even though those lines are perfectly clear.

So when a progressive system stops feeding everywhere at once, the fault is usually a single blocked outlet or line, not the pump. Work along the distributor outlet by outlet to find which one has stalled.

One stalled outlet halts every point on the distributor.

Air in the pump chamber breaks delivery

A pump that runs normally, sounds normal and shows a normal cycle, but delivers erratically or not at all, usually has air trapped in the pump chamber. Air compresses; lubricant does not. Each stroke spends itself compressing the trapped air instead of moving grease down the line.

This is common after a reservoir has been run empty, after a refill, and on first commissioning — any point at which air can be drawn in. It is why grease pumps are fitted with a vent valve specifically for removing air from the pump chamber and restoring smooth delivery.

Bleed the pump through the vent valve until lubricant runs free of bubbles, then check delivery again at the first distributor before working further down the system. The procedure for your model is in its manual.

Air in the chamber: the pump cycles, delivery does not follow.

Fault finder

Symptoms, causes and what to check

Work down the "check" column in order — it runs from the most common cause to the least.

Delivery faults

Delivery faults: symptom, likely cause and what to check
Symptom	Likely cause	What to check
Pump cycles, little or no delivery anywhere	Air trapped in the pump chamber	Bleed through the vent valve until lubricant runs clear of bubbles. Check the reservoir has not been run empty and that the suction side is not drawing air.
Progressive system: every point stops together	One blocked outlet or line has stalled the cycle	Work along the distributor outlet by outlet to find the stalled one. Check for a blockage alarm or a pressure rise at the pump.
Volumetric or resist system: one point dry, the rest fine	Blocked line, blocked outlet or a failed metering element on that outlet alone	Disconnect that line at the distributor and confirm whether the outlet discharges. If it does, the fault is downstream in the line or fitting.
Delivery falls off across the whole system	Clogged filter, or lubricant too stiff for the system	Check and clean the filter. Confirm the grade in use is within range for the pump and distributor type.
Grease will not feed at all in cold conditions	Grade too heavy for the ambient temperature	Confirm the NLGI grade against the manual. Grease systems generally run on 000# to 2#; the stiffer end of that range needs a pump rated for it.
Points over-greased, lubricant escaping at the seals	Interval too short, or dose set too high	Review the work and rest times set on the controller or in the machine PLC. Over-delivery wastes lubricant and contaminates the machine.

Leaks

Leaks: symptom, likely cause and what to check
Symptom	Likely cause	What to check
Lubricant pooling under the machine	Most often a distributor, not the pump	Inspect the distributors and their outlet fittings first — this is the usual source and the easiest to see. Work back to the pump only if they are dry.
Weeping from the pump body	Worn or damaged seals, or loose fasteners	Check the sealing parts inside the pump body and confirm the body fasteners are properly seated.
Leak at a joint or hose end	Fitting loosened by vibration, or a damaged hose	Re-seat the fitting. On high-pressure lines, inspect the hose for damage rather than simply tightening.
Reservoir empties faster than expected	A leak, or over-delivery	Rule out leaks first, then review the cycle timing. A system losing lubricant with no visible leak is usually over-delivering at the points.

Electrical, control and monitoring

Electrical and monitoring faults: symptom, likely cause and what to check
Symptom	Likely cause	What to check
Pump does not start	Supply, or an interlock in the host equipment	Check the run indicator, the external supply and the equipment supply, and the linkage between them. On PLC-controlled systems, confirm the machine is actually calling for a lubrication cycle.
Pump runs continuously and will not rest	Controller settings, or a failed pressure switch	Check the work and rest times on the controller. Test the pressure switch with a multimeter — a switch that never signals can leave the pump running.
No alarm despite an obvious fault	Sensor not responding	Test each sensor in turn with a multimeter and eliminate them one by one.
Low-level alarm with lubricant still in the reservoir	Level switch fault	Test the level switch. Confirm the lubricant has not channelled away from the pick-up, leaving the switch uncovered.
Gauge reads zero while the pump runs	Break in the delivery line, or no delivery at all	Inspect the line for a break or disconnection, then return to the delivery faults above.

First fill

Commissioning a new system

A new system rarely fails because a part is wrong. It fails because air is still in it, the pressure is set for a different machine, or grit went in with the first fill. Work through these before the machine goes back into production.

1. Purge the air first

Air in the pump chamber is the single most common commissioning fault. It compresses instead of delivering, so the pump cycles normally and nothing reaches the points. Run the pump with the outlet open, or use the vent valve where the pump has one, until lubricant comes through clean and steady with no bubbles. Only then connect the line.

2. Fill the lines before the points

Prime the main line up to the distributor, then each feed to its point, rather than expecting the first cycle to fill an empty system. On a long run this can take several cycles — a point that looks dead on cycle one is often just still filling.

3. Set the working pressure

Where the pump has a pressure regulating valve, set it to the system's working pressure rather than leaving it at whatever it shipped with. Too low and the far points never see a dose; too high and you are stressing the pump and the seals for no benefit.

4. Confirm every point, once

Crack each outlet fitting in turn and watch for delivery before you sign the system off. On a progressive system the whole bank stalls if any one point is blocked, so one missed connection stops everything downstream of it — easier to find now than on a hot bearing later.

5. Keep the first fill clean

Grit carried in with the lubricant is the most common cause of a blocked distributor. Wipe the filler and the container rim before filling, and use the grade the pump is rated for — see choosing the right lubricant.

6. Prove the alarms

Test the level switch and the pressure switch before you rely on them. A blockage alarm that was never wired up is indistinguishable from a system that has never blocked, and you will not find out which until a bearing fails.

Keeping it running

Routine maintenance

A centralised system needs very little attention, but it needs it consistently. These intervals are a starting point — follow the manual for your model where it differs.

Routine maintenance schedule
Interval	Task	Why
Each shift	Check the reservoir level and the run indicator	Running a reservoir empty draws air into the chamber, which is the most common cause of lost delivery.
Weekly	Walk the machine for leaks and check delivery at a sample of points	Catches a stalled outlet or a weeping fitting before a bearing runs dry.
Monthly	Inspect distributors and outlet fittings	The distributor is the usual source of leaks and the first place a blockage shows.
Quarterly	Clean or replace the filter; test the pressure and level switches	A clogged filter starves the system; an untested switch gives false confidence that alarms will fire.
On refill	Refill before the reservoir empties, and bleed if air was drawn in	Refilling early avoids the bleed entirely.
On commissioning	Bleed the pump, then confirm delivery at every point	Confirms the system before it is relied on, and establishes what normal looks like.

New oil going into a volumetric system does not need to be filtered first. And because volumetric distributors meter by piston displacement, the dose at each point stays the same regardless of pump pressure or pipe run — so a point that has gone dry points to a blockage or a leak, not to a system that has drifted out of adjustment.

Model-specific procedures

Manuals

Bleed points, pressure settings, exploded views and service parts are model-specific. Each manual covers composition, working principle, specifications and installation.