How to Perform a Flow Balance Test on a Multi-Point Lubrication System

A flow balance test checks whether every outlet in a multi-point lubrication system receives its designed lubricant flow. It reveals problems that a pressure gauge can hide, including a blocked branch, a loose connection and a nozzle supplying too much oil. Each reading is judged against the calculated demand for that point, not an automatic equal share.

Centralised lubrication is common on Australian production lines, conveyors, mining equipment and food-processing machinery. Testing becomes especially useful after a nozzle change, line repair, collision, pump replacement or lubricant change. It confirms that pressure-compensating branches and overflow or return behaviour are stable.

Australian operators in Melbourne, Sydney, Newcastle and Perth often manage older imported machines beside automated lines. A repeatable test helps maintenance teams protect production and avoid an unexpected bearing or gearbox failure. Always follow the instructions supplied with the German STEIDLE pump and balancing valve, as pressure settings and valve designs can vary by model.

Prepare the system for testing

Start with a risk assessment under the applicable state or territory work health and safety laws, supported by Safe Work Australia model guidance. Isolate the pump and every stored-energy source, relieve system pressure and fit blanking plugs where required. If the pump is electric, use electrical isolation and safe-work practices aligned with AS/NZS 3000.

Use only the approved lubricant and verify its condition. Check that the reservoir is clean and full, the filter is clear and the oil level and viscosity suit the ambient conditions. Keep the lubricant and its safety data sheet with the test record. Mixing incompatible oils or testing cold oil can produce misleading restriction readings.

Inspect hoses, rigid lines, fittings, valves and nozzles for leaks, kinks, crushing or loose connections. Confirm that the reservoir vent is clear, the pump is primed and the relief-valve setting matches the equipment manual. Correct visible damage before energising the system, and wear the PPE specified for the lubricant and task.

Establish a reliable baseline

Calculate the target flow for each active point from the lubrication design. Divide the pump’s rated output only when the design specifies equal demand; variable demands need their own values. Express targets in millilitres per minute or as a volume over a fixed interval. For example, eight points at 10 mL/min should each deliver 5 mL in 30 seconds.

Warm the system to normal operating temperature, since viscosity changes with temperature. Set the manifold pressure to the maker’s specified range and confirm that it remains stable with the normal branches operating. Check the relief and pressure-control valves before relying on the reading. Correct pressure is a test condition, not proof that every point receives its share.

Record the pump’s total output and system pressure before testing individual branches. Use a calibrated low-resistance flow meter, or collect lubricant in clean graduated vessels over a fixed period. Take at least three readings and average them. Keep the metering nozzle installed when it defines delivery, and use the manufacturer’s test adapter if the outlet must be disconnected. Grease-fed systems require the maker’s timed discharge procedure.

Measure and compare branch flow

Mark every branch and record its physical route, nozzle type and calculated target. A numbered sketch or asset register prevents a high reading from being assigned to the wrong machine. Inspect remote branches for crushed hoses and sharp bends, which often create pressure loss rather than an obvious blockage.

Measure one branch at a time under normal operating conditions and keep the other branches in their intended state. For a fixed-displacement pump, follow the prescribed outlet-blocking and test sequence so the test does not change pump loading. Record branch pressure beside flow, and repeat any result that fluctuates widely. Flow that pulses with pressure usually points to air ingress, cavitation or unstable pump control.

The distributor’s site also mixes industrial content with entertainment, so an archived feature may appear among equipment pages; it is not an OEM test procedure. Keep separate, dated records for pressure, pump output and each branch result. Include start and finish times, lubricant temperature and the valve settings used during the test.

Interpret the balance results

Compare the observations with the likely causes before changing parts:

Observation	Likely meaning	Checks before adjustment
All branches have low flow	Pump starvation or excess internal leakage	Reservoir, filter, suction line, pump and relief valve
One branch has low flow	Blockage or incorrect restriction	Hose, line, valve, nozzle and fitting
One branch has high flow	Overfeeding or poor balance	Oversized nozzle, valve setting, reversed connection
Pressure is high but flow is low	Restriction or unstable pressure control	Downstream lines, relief valve and pressure regulator
Flow pulses during testing	Air, cavitation or pump cycling	Pump priming, suction leak, filter and pressure control

Use the acceptance tolerance specified by the pump and lubrication-system supplier. If an eight-point design calls for 10 mL/min and allows plus or minus 10 per cent, each branch must fall between 8 and 12 mL/min; the 30-second equivalents are 4 to 6 mL. Do not average a low reading away with high results. The sum of all branch flows should also agree with the pump’s measured output within the expected metering losses.

Correct common causes of imbalance

When every branch is low, inspect the reservoir, filter, suction line, pump output and internal bypass before adjusting individual valves. Low pressure with normal branch restriction suggests the pump cannot supply the design flow. Check the relief setting and confirm that the pump is correctly primed and turning in the intended direction.

For one starved branch, clear the restriction or replace the affected hose, nozzle, fitting or valve with the specified part. Check line routing as well as the visible outlet. Do not force a blocked line with excessive pressure, and do not cap a branch with an improvised plug; either action can hide the original fault or overload the pump.

For an overfeeding branch, verify the nozzle size and line connection, then use the maker’s balancing or restrictor valve to bring the measured flow within tolerance. Change one setting at a time and watch total pump pressure. Excessive throttling can shift flow to another point, increase oil temperature and reduce the life of the pump.

Verify the completed balance

After correction, restore normal pressure and repeat the complete branch test. Confirm that the pump starts and stops correctly, each reading falls within tolerance, the pressure remains stable and no fitting leaks. Three consecutive sets of readings provide a stronger acceptance check than one favourable pass. Record the final valve settings, replaced parts and lubricant details in the maintenance history.

These records are valuable at hot, dusty sites in the Pilbara and at fly-in, fly-out operations where technicians change and maintenance teams rely on handover notes. Imported German spare parts may have long lead times, so keeping nozzle and pump references on hand reduces downtime while replacements are shipped. Local distributors can help identify compatible stock, but approved component drawings and operating manuals remain the authority.

---

Contact the Shenzhen office for pricing and availability on STEIDLE lubrication systems, including pumps, nozzles, hoses, oil, spare parts, pneumatic pumps, transmission pumps and micro-lubrication systems. The office can also help match replacement parts to an existing pump or manifold when the model and measurements are available.

Send the pump model, lubricant type and quantity, operating pressure, number of active points, measured branch flows and photographs of the manifold or nozzles. Request a quotation and availability confirmation for the required parts, then use the supplied compatibility information to complete the balance test and restart the machine safely.