Tennant T300 Walk-Behind Scrubber Preventive Maintenance SOP

Why this matters

The Tennant T300 is the workhorse autoscrubber in commercial janitorial fleets: 20-, 24-, and 28-inch deck widths, sealed lead-acid or AGM battery options, and the ec-H2O NanoClean module on T300e variants. When a T300 fails mid-shift the entire square footage on the route slips to manual mop-and-bucket, which costs four to six hours of labor and a callback. Tennant's published service life on a T300 is 5,000 hours of operating time, and every operator-skipped inspection compounds wear in the squeegee, brush motor brushes, and recovery tank float shutoff. A disciplined 30/90/365-day PM cadence keeps the machine on its rated runtime, preserves battery capacity at over 80 percent at year three, and prevents the two most common service-call drivers: a streaking squeegee and a recovery tank that overflows water into the vacuum motor.

Daily operator inspection (before key turn)

The operator performs this at the start of each shift. No tools.

1. Walk around the machine. Look for fluid puddles under the solution tank and battery compartment. A solution puddle means a cracked tank or a loose drain hose clamp. A clear puddle near the batteries is the AGM venting electrolyte and the battery is a replace.
2. Lift the recovery tank lid. The tank should be empty and the debris tray clean. Pull the debris tray, dump, and rinse. Inspect the float ball shutoff at the top of the tank; it must move freely. A stuck float is the number one cause of vacuum motor flooding on T300s.
3. Check the squeegee blades. Both front and rear blades should be uniform thickness with no nicks, no curl, and no embedded grit. A nicked blade streaks water onto the freshly scrubbed floor. Rotate blades 180 degrees when one edge is worn; replace at the second rotation.
4. Inspect the scrub brush or pad. Bristles shorter than 0.5 inch are end-of-life. A pad worn past the colored backing is end-of-life.
5. Pull the solution tank drain hose down briefly. Any sediment indicates the solution filter screen is bypassed or missing.

Log the inspection in the equipment log. Tennant T300 operator manual requires daily pre-shift sign-off for warranty validation.

30-hour PM (weekly on heavy routes)

Battery and motor service. PPE: nitrile gloves, safety glasses.

1. Verify battery state of charge. Tennant ships the T300 with a built-in BDI gauge. Charge to full green before any timed-runtime test. AGM batteries that fall below the second LED segment under no-load are sulfated and trending to replacement.
2. Check battery water on flooded lead-acid units only (Trojan T-105 or equivalent). Distilled water only. Fill to 0.25 inch below the vent tube split ring after a full charge cycle, not before. Adding water before charging is the most common reason for boil-over and corrosion on the battery tray.
3. Wipe battery tops and terminals. A baking soda paste neutralizes acid film; rinse with distilled water and dry. Spray terminals with NCP-2 or equivalent terminal protectant.
4. Inspect the squeegee tool linkage. The squeegee should drop fully when the lever is engaged and lift fully on disengage. Adjust the cable tension at the squeegee yoke if the rear blade does not contact the floor evenly across its full width.
5. Vacuum hose inspection. Pull the hose from the squeegee tool and check for cracks, soft spots, and embedded debris. A pinhole leak in the vacuum hose drops recovery vacuum by 40 percent at the squeegee.
6. ec-H2O module flush (T300e only). Run the module flush cycle per the operator panel sequence. Tennant requires this every 30 operating hours to prevent calcium scaling in the conditioning cell.

90-day PM (quarterly)

Drive-system, brush-drive, and tank service. PPE adds: safety boots, lockout device.

1. Lockout. Disconnect the battery cable at the main connector. Verify zero voltage at the brush motor terminals before any further work.
2. Pull the scrub deck. Inspect the brush drive belt for cracks and glazing. Belt deflection should be 0.25 to 0.5 inch at midspan under finger pressure. Replace if cracked or glazed.
3. Inspect carbon brushes in the brush motor (24-volt DC motor on T300). Brushes shorter than 0.375 inch are end-of-life. Tennant sells the brush kit as a service part. Replace as a matched set.
4. Drain and flush the solution tank. Use a degreaser like Tennant FaST or equivalent neutral pH cleaner. Run two gallons of clean water through the solution line and out the deck to clear residual chemical. Pull the solution screen filter, rinse, and reinstall.
5. Drain and flush the recovery tank. Scrub the interior with a long-handle brush. Sanitize with a quaternary disinfectant dilution per the chemical label. A neglected recovery tank harbors bacteria and produces the unmistakable "dirty mop" smell that complaint calls reference.
6. Inspect drive-wheel tread. Worn tread reduces traction on wet floors and the machine spins on inclines.
7. Function-test the brake. The T300 has a parking brake on the drive wheel. Engage and verify the machine holds on a 5 percent grade.

Annual PM (every 1,000 hours or 12 months, whichever comes first)

Major overhaul. Typically performed by a Tennant-authorized service tech for warranty preservation; in-house techs can perform if certified.

1. Replace all squeegee blades regardless of visible wear. Rubber compounds harden over time and a year-old blade streaks even when geometry looks correct.
2. Replace the vacuum motor carbon brushes. The vacuum motor on a T300 is a series-wound 24-volt brushed motor with a Tennant-recommended brush-replacement interval at 1,000 hours.
3. Battery load test. AGM and flooded batteries that drop below 10.5 volts under a 75-amp load (Midtronics or equivalent tester) are at end-of-life. Replace as a matched set; mixing old and new batteries cuts pack life by half.
4. Replace the solution filter screen and any soft hose that shows compression set.
5. Inspect the chassis frame for cracks at the front-caster mount. T300s used on uneven loading docks crack here first.
6. Update the operator panel firmware via the Tennant service tool if a release is available. Tennant publishes T300 firmware notes through the IRIS service portal.
7. Document the PM in the equipment log with hours-meter reading, parts replaced, and tech initials. This record is required for warranty claims and for resale value when the machine is rotated out of fleet.

Parts to stock on the van

For a fleet of 5+ T300s the stock list pays back inside a quarter:

• Squeegee blade kit (front and rear urethane). 8 to 10 dollars MSRP per blade through Tennant parts. Buy at least four kits.
• Brush motor carbon brush set.
• Vacuum motor carbon brush set.
• Solution filter screen.
• Drain hose with clamp.
• Recovery tank float ball assembly.
• Battery terminal protectant spray (NCP-2 or equivalent).

References

• Tennant Company. T300 / T300e Operator Manual. Tennant Part No. 9007860, rev. 06.
• Tennant Company. T300 Service Manual. Tennant Part No. 9007861.
• ISSA. The Official ISSA 612 Cleaning Times. ISSA, current edition.
• OSHA. 29 CFR 1910.147 - The Control of Hazardous Energy (Lockout/Tagout). Required for battery and motor service.
• Battery Council International. Recommended Practice for Flooded Lead-Acid Battery Maintenance, BCI RP-2020.