“It ran before cleaning, but now it will not restart. Has the rubber swollen?” That is one possibility to investigate. The timing matters, but a restart problem alone does not establish what changed inside the pump.
These five checks help prepare a material review. If the pump is locked or repeatedly trips, stop the restart attempts and follow the site fault procedure. Do not force it to turn or raise a drive limit to test whether it will free itself.
1. Identify the Mixture and the Actual Rubber Compound
Names such as “oil,” “slurry,” or “wash water” leave too much open. Provide the product name, available composition and concentrations, carrier liquid, and known additives or contaminants. Include the current product information or safety data sheet where available, and identify any composition details still unknown.
Check the fitted rotor material against its part or order record. NBR, EPDM, and FKM/FPM are material-family names, not complete compound specifications. Ask which grade and hardness were supplied and what compatibility information supports the proposed replacement. Do not identify a compound by color or choose a different rubber from a generic chart alone.
2. Include Cleaning, Flushing, and Shutdown Exposure
List each cleaning or flushing liquid separately from the normal product. Record the chemical or product name, working concentration, temperature, contact time, and sequence. A cleaning product’s concentrate and its diluted working solution are different exposure conditions, so say which value you are providing.
Note what remains in the chamber during a stop, how long it stays there, and whether the pump is drained or rinsed under its normal procedure. If the problem followed cleaning, that history is relevant, but it does not by itself prove the cleaner caused the fault. Do not introduce a different cleaning liquid without checking the pump and process requirements.
3. Give Temperatures Together with Exposure Times
A compatibility rating needs its conditions. Ask whether the supporting data covers the actual compound, liquid concentration, and exposure temperature. A general temperature range for the rubber family is not confirmation of compatibility with every liquid within that range.
Give normal running and startup temperatures, the highest cleaning temperature, and how long each lasts. State whether the values are measured or estimated. Identify any hot-water or steam exposure rather than assuming the pump configuration is approved for it.
4. Separate the Symptoms from the Diagnosis
High current, scuff marks, rubber debris, heat, or a failed restart can justify inspection. They do not distinguish chemical swelling from trapped material, an assembly or clearance issue, or another mechanical fault. Record when the change began and what happened beforehand, including cleaning and recent repairs.
After safe isolation and disassembly under the service procedure, record the rotor condition and any specified measurements. Identify the measurement locations, temperature, and time since removal, and compare with the correct model and part data. Photos of deposits, cracks, contact marks, and changed dimensions are useful evidence; they do not identify the chemical cause on their own.
5. Check What Has Changed before Reordering
The serial number helps identify what was supplied. It does not confirm that today’s process is unchanged. Tell the supplier about a new product, different cleaning recipe, higher temperature, longer shutdown, or a previous material substitution. Include the operating hours and service history of the affected rotors.
Ask for the proposed part reference, compound, and configuration to be confirmed before ordering. Changing to another elastomer or to a metal rotor is not a like-for-like substitution unless the manufacturer confirms the required configuration and operating limits. Keep any unresolved compatibility questions visible in the enquiry.
Use the spare-parts enquiry template and add the exposure sequence described above. The Materials Guide covers the information to prepare for material selection. Send what is known and mark missing details as unavailable.
