Tennant T600 Losing Suction? How to Fix Weak Vacuum Pickup on Your Walk-Behind Scrubber

Your T600 sounds fine. So why is the floor still wet?

The vac motor is humming and the brushes are scrubbing. But when you look back, there are puddles at the ends of the squeegee, streaks down the aisle, or a film of dirty water drying where it shouldn’t be.

When a Tennant T600 walk-behind loses suction, the motor is rarely the problem. Usually air is getting into the system somewhere, or something is blocking the path between the squeegee and the recovery tank. Most of the fixes are free, and most take a few minutes with no tools.

In the video below, our technician walks around a T600 and shows you every spot to check, from the tank lid down to the squeegee. Follow along at the machine.

How T600 suction works

The T600 picks up water through one sealed loop:

1. The squeegee at the back gathers dirty water off the floor.
2. The vacuum hose carries it from the squeegee up to the recovery tank.
3. The vac motor pulls air out of the recovery tank through a filtered inlet under the lid.
4. That pull creates the vacuum that lifts water from the floor into the tank.

The whole system depends on an airtight seal. If air sneaks in anywhere, through a lid that won’t seal, a loose drain cap, or a squeegee riding off the floor, suction drops everywhere. That’s why the checks below follow the air path from the top of the machine down to the floor.

Start at the recovery tank

Open the recovery tank lid and prop it up. Most suction problems on a T600 show up right here.

Check 1: Empty the debris tray

The yellow debris tray catches trash as dirty water pours into the tank. When it’s packed full, water and debris back up near the inlet. Empty and rinse it after every shift.

Check 2: Clean the vac inlet filter

Under the lid, a cylindrical screen filter sits over the vac motor inlet. It keeps debris and foam out of the motor.

Pull it off and look closely:

• Clogged with lint, hair, or sludge? Rinse it until you can see through the screen.
• Torn or crushed? Replace it. Never run the machine without it, because trash pulled into the vac motor can damage it.

Check 3: Feel the suction

With the filter back on and the vacuum running, put your hand over the vac hose opening on the tank. You should feel a strong, steady pull.

• Strong here? The motor and the top of the system are fine. Move down to the hose and squeegee.
• Weak here? The leak is up top. Check the lid gasket and drain cap next.

Seal the tank

Check 4: Inspect the lid gasket

The rubber gasket around the recovery tank lid is what makes the tank airtight. If it’s torn, peeling, flattened, or caked with dirt, air leaks straight in and the vac motor can’t pull water up the hose.

Run your finger around the whole gasket. Wipe it clean, press loose sections back into place, and replace it if it’s cracked or torn. Then close the lid and make sure it sits flat all the way around.

Check 5: Make sure the drain hose cap is tight

The recovery tank drain hose hangs at the back of the machine. If its cap is loose, cracked, or missing, the tank pulls air through it instead of through the squeegee. Screw it on snug every time you drain the tank.

Move down to the squeegee

Check 6: Clear the hose and inspect the blades

Squeegee hose. Pull the vacuum hose off the squeegee and feel for suction at the open end. It should feel about as strong as it did at the tank.

• Weaker at the squeegee end? Something is stuck in the hose. Straighten it, flex it, and shake the clog loose. Check for cracks or splits along the ribs while you’re there.
• Strong at the hose but still poor pickup? Look inside the squeegee body for wedged-in trash, wire, or debris blocking the opening.

Squeegee blades. Loosen the yellow knobs and take the squeegee off to check the rubber.

• The rear blade needs a crisp, square edge to wipe the floor dry. If the edge is rounded or nicked, flip or rotate the blade to a fresh edge.
• The front blade should have no big tears. A rip lets air rush in and kills suction.
• Once a blade has no good edges left, replace it.

Check 7: Set the squeegee height and tilt

Lower the squeegee and watch the rear blade as you push the machine forward. You want a slight, even bend along the whole blade. If it stands straight up, skips, or barely touches the floor, air gets in under it and water gets left behind.

• Squeegee wheels. The small wheels at each end of the squeegee set how high it rides. Make sure they spin freely and aren’t worn flat, cracked, or set so low that they lift the blade off the floor.
• Tilt adjustment. The squeegee mount has an adjustment (marked with up and down arrows) that sets the squeegee’s angle. If the middle is dry but the ends leave water, or the reverse, adjust it a little at a time until the blade touches evenly from end to end.
• Bumps knock it out. Backing into a rack or a doorframe can bend the mount. If the squeegee suddenly starts leaving water after a hit, check the alignment first.

The T600 suction checklist

Print it and keep it near the charger.

• Debris tray emptied and rinsed
• Vac inlet filter clean and undamaged
• Strong suction at the tank’s hose opening
• Lid gasket clean, intact, and sealing flat
• Drain hose cap on tight
• Squeegee hose clear, with no cracks
• Rear blade has a square edge and front blade has no tears
• Squeegee wheels roll freely and the blade bends evenly

Still leaving water behind? We’ll help you find it.

Most of these fixes cost little or nothing. The real cost of weak suction is the re-cleaning, the slip hazards, and the labor hours you don’t get back.

If you’ve worked through the list and your T600 still won’t pick up, PowerKleen can get you the right parts or send a tech.

• Need a filter, gasket, squeegee blades, or a hose? Visit our Parts & Assistance page and we’ll match the right part to your machine.
• Want a pro to take a look? Get on the schedule now through our Service Request page.

Rather talk it through? Give us a call. We’re happy to help you figure out what’s going on.