HTST Pasteuriser Troubleshooting: Causes & Fixes

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Problems on this page:

Frequent flow diversions Fouling shortens production runs Regeneration efficiency falling, energy climbing Recorder and indicating thermometer disagree Plate pack leaks or pinholes Timing pump or booster pump faults Flow diversion valve not seating Product not cooled enough at the outlet

Frequent flow diversions

Hits OEE: Availability

Symptoms: Divert valve kicks product back to balance tank, throughput collapses, restarts burn time and product.

Hot water or steam supply unstable

Fix the heating loop first: verify steam pressure, hot water set point stability and control valve behaviour.

Fouled plates reducing heat transfer

Shorten run time between cleans for the recipe or improve CIP; trend the temperature approach to spot fouling early.

Flow rate instability

Check the timing pump, homogeniser coordination and level control in the balance tank.

Prevention: Trend holding-tube temperature margin, heating loop PM, CIP effectiveness verification.

Fouling shortens production runs

Hits OEE: Performance

Symptoms: Pressure drop climbs across the plate pack, temperature approach widens through the run, runs end early for cleaning.

Protein or mineral fouling faster than planned

Review product preheat and regeneration temperatures; small profile changes slow deposit formation.

CIP not restoring the plates

Verify chemical strength, temperature and flow in CIP; inspect plates periodically instead of trusting cycle completion.

Plate gaskets aging

Replace gaskets on schedule; leaking gaskets disturb flow distribution and hot spots foul faster.

Prevention: Run-length and pressure-drop trending, periodic plate inspection, gasket replacement intervals.

Regeneration efficiency falling, energy climbing

Hits OEE: Performance

Symptoms: Steam and chilled water consumption rise for the same throughput, product enters heating colder than design.

Regeneration section fouled

Include regen sections in cleaning verification, not just the heating section.

Flow imbalance between passes

Check for blocked channels and verify differential pressures against commissioning data.

Instrument drift hiding the loss

Calibrate the temperature sensors around the regen section so efficiency numbers are real.

Prevention: Energy per litre trending, commissioning-baseline comparisons, sensor calibration cadence.

Recorder and indicating thermometer disagree

Hits OEE: Quality

Symptoms: The recorded holding temperature differs from the indicating thermometer at the holding tube.

Sensor calibration drift

Calibrate the sensors against a reference on the schedule your regulator and plan require.

Sensor position or immersion wrong

Check sensor position and immersion.

Recorder fault

Have the recorder checked and repaired.

Prevention: Calibration on schedule with records kept.

Plate pack leaks or pinholes

Hits OEE: Quality

Symptoms: External leaks at the plate pack, or a pressure or dye test showing a breach between sections.

Gasket failure

Replace failed gaskets with the OEM's specified gaskets.

Cracked or corroded plates

Test plates for cracks and pinholes and replace damaged ones.

Pressure difference between sections not held

Check the pressure controls that keep pasteurised product at the higher pressure.

Prevention: Plate inspection and leak testing on a schedule.

Timing pump or booster pump faults

Hits OEE: Availability

Symptoms: Flow rate changes, pump alarms, the pasteuriser will not go to forward flow.

Worn timing pump changing the flow

Service the timing pump and recheck holding time as your plan requires.

Booster pump interlock faults

Check the booster pump interlocks.

Drive faults

Check the pump drives for alarms.

Prevention: Pump service on a schedule and holding time checks after any pump work.

Flow diversion valve not seating

Hits OEE: Quality

Symptoms: The valve leaks in the divert position or does not move fully, position alarms.

Worn valve seals

Replace the valve seals.

Air supply to the actuator low

Check the actuator air supply.

Position feedback faulty

Check the valve's position sensors.

Prevention: Diversion valve tests on the schedule your plan sets.

Product not cooled enough at the outlet

Hits OEE: Quality

Symptoms: Outlet temperature above the product spec.

Chilled water too warm or too little flow

Check the chilled water supply.

Cooling section fouled

Clean the cooling section.

Regeneration imbalance

Check flows through the regeneration section.

Prevention: Outlet temperature trended every run.

Guidance only. Always follow lockout/tagout and your site's safe-work procedures, and verify against OEM manuals before acting.

Stop the same fault coming back

Recurring HTST pasteuriser stops usually trace to a cause you cannot see by hand. The partner we recommend is Fabrico: it tracks OEE and downtime live from PLCs, IoT sensors or AI cameras; where cameras are fitted, the video of a stop sits next to its machine data so the cause can be reviewed; and a technician opens the work order from the stop in the same system. Data is hosted in the AWS EU region, and Fabrico and the company behind it hold ISO/IEC 27001, ISO/IEC 20000-1 and ISO 9001.

Book a Fabrico demo

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Methods that cut recurring stops: the six big losses · root cause analysis · preventive vs predictive maintenance · TPM · SMED & changeover