How to Repair the Nobles SS5 / Tennant T5e Floor Scrubber: Troubleshooting Guide for Common Problems

Key ON Power DistributionService Manual · Page 38

Circuit Breakers, Fuses & Charger SettingsService Manual · Page 10

Component Panel GroupInteractive Parts Manual

Also in the parts manual: Component Panel (S/N 10000000–10722198) · Control Console Group

2Battery Meter LED Fault Codes

The row of LED bars on the battery meter does double duty as the machine’s diagnostic display. A flashing pattern is a fault code — count the bars, note whether they flash slowly or quickly, and match it below.

Bars flashing	What it means	What to do
1 bar	Very low battery voltage – scrubbing stops (low-voltage shut-off)	Recharge the batteries immediately and check the battery connections.
2 bars, slow	Battery charge getting low	Recharge the batteries; check the connections to the batteries.
2 bars, fast (200 Hz)	Propel motor open circuit (service manual)	Check all connections and wires between the transaxle motor and the control board; test the motor for an open circuit.
3 bars	Drive motor tripped / propel motor shorted	Remove the overload and cycle the key. If it returns, check the wiring and motor for a short circuit.
4 bars	Battery lockout – voltage fell below the lockout level	Recharge the batteries immediately; certain machine functions are inhibited until you do.
8 bars	Controller tripped / possible control board fault	Make sure all connections are secure; if the fault persists, take it to an authorized service center.
10 bars	High battery voltage reading	Usually a poor battery connection – check and tighten all battery connections.
LEDs one at a time, left to right	Control board in sleep mode	Turn the key off and back on.
LEDs rippling back and forth	Throttle engaged at start-up (throttle displaced)	Release the forward/reverse triggers before switching the machine on; if it persists check the switch wiring to the control board.
No bars	Sleep mode	Turn the key to restore.

Good to know: The 2-bar code appears twice in the service manual. The slow flash is a low battery; the fast 200 Hz flash is a propel motor open circuit — very different repairs.

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Battery Meter LED Fault CodesOperator Manual · Page 38

BDI Diagnostic Fault IndicatorsService Manual · Page 33

Control Console GroupInteractive Parts Manual

Also in the parts manual: Frame Group (transaxle) · Battery Group

3Battery Charger Will Not Charge or Shows an Error Code

Two things cause most charging complaints: the charger is set for the wrong battery type, or a code is telling you something the battery needs. The on-board charger puts its diagnosis right on the display.

On-board charger will not operate

Possible cause	What to do
Plug not connected to a power supply	Check the plug connection and that the outlet is live and properly grounded.
Faulty charger fuse	Replace the charger fuse. 15 A charger fuse (1030692)
Faulty power supply cord	Replace the cord. AC power cord (1025642)
Error detected	Read the display code and use the table below.

On-board charger error codes

Display	Fault	Solution
bat	Loose or damaged battery cable – or battery exceeded maximum voltage	Check the battery cable connections.
E01	Exceeded maximum battery voltage allowed	No action necessary.
E02	Safety thermostat exceeded maximum internal temperature	Check whether the charger vents are obstructed.
E03	Exceeded maximum time for the charging phase – batteries undercharged (sulfated or faulty battery)	Repeat the charging cycle. If E03 returns, check the battery or replace it.
SCt	Safety timer exceeded maximum charging time – cycle interrupted	Replace the battery.
Srt	Possible internal short circuit	Contact an authorized Tennant service center.

Check the charger setting first

The charger must be set for your battery type before charging, or you will damage the batteries. Plug the charger in and watch the display sequence — it will read GEL (sealed / maintenance-free batteries) or Acd (wet / lead-acid batteries). To change it, unplug the charger, peel up the corner of the display label and set the switches to match the battery type. A normal cycle runs red, then yellow, then green; green means the cycle is complete.

Charging checklist: Park in a well-ventilated area on a flat, dry surface, key off. For wet batteries, check the fluid level first and prop up the recovery tank for ventilation. Batteries give off hydrogen — keep sparks and open flame away. If you use an off-board charger, never disconnect the DC cord from the machine while it is running; unplug the AC cord first.

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Charging BatteriesOperator Manual · Pages 20–23

Circuit Breakers, Fuses & Charger SettingsService Manual · Page 10

Using the On-Board Battery ChargerService Manual · Page 11

Charger Error Codes & Off-Board ChargerService Manual · Page 12

On-Board Charger Group (S/N 10409250 & up)Interactive Parts Manual

Also in the parts manual: On-Board Charger (S/N 10000000–10409249)

4Short Run Time and Battery Problems

A properly maintained wet-cell set should deliver up to 5 hours of continuous scrubbing; sealed gel batteries up to 4 hours. If you are getting far less, work through this list.

Possible cause	What to do
Batteries not fully charged	Fully recharge. Recharge after any use totaling 30 minutes or more, and do not leave batteries discharged for long periods.
Defective batteries	Replace the battery (always replace in a matched set of four 6 V batteries if the set is old).
Batteries need maintenance	Water wet batteries, clean the tops and terminals, and tighten connections (see below).
Faulty battery charger	Repair or replace the charger (see Problem 3).

Wet (lead-acid) battery care

Check the electrolyte weekly. Before charging, the level should be slightly above the plates. Add distilled water if low — do not overfill, because the electrolyte expands and can overflow while charging.
After charging, distilled water can be topped up to about 3 mm (0.12 in) below the sight tubes.
Every 200 hours, check for loose connections and clean the battery tops, terminals and cable clamps with a scrub brush and a strong baking soda and water mixture. Keep the caps on while cleaning.
Maintenance-free (sealed AGM) batteries need no watering, but still need cleaning and routine checks.
Storing the machine? Charge the batteries first, disconnect them, and recharge about once a month.

Safety: Wear gloves and eye protection when working on batteries and cables, and avoid contact with battery acid.

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Charging BatteriesOperator Manual · Pages 20–23

Battery Installation & Squeegee RemovalService Manual · Page 9

Battery Maintenance & Squeegee BladesService Manual · Page 18

Battery Group, Lead-Acid 235 AhInteractive Parts Manual

Also in the parts manual: Battery Group, Maintenance Free 220 Ah · On-Board Charger

5Brush Motors Will Not Run

Scrub head is down, key is on, triggers are pulled — and the brushes do not turn. The brush motors each have their own 25 A circuit breaker, so check the simple stuff before blaming a motor.

Possible cause	What to do
Scrub head is raised off the floor	Lower the scrub head.
Battery meter lockout activated / discharged batteries	Recharge the batteries.
Tripped brush motor circuit breaker	Reset the 25 A circuit breaker (left brush = C, right brush = D). 25 A breaker (383724)
Broken or loose belt (cylindrical models)	Replace or tighten the belt. Drive belt (1035888)
Worn carbon brushes	Replace the carbon brushes. Disk motor brushes (1031775) · Cylindrical motor brush kit (1049739)
Faulty brush motor or wiring	Test and replace. Disk brush motor (1023067) · Cylindrical brush motor (1042228)
Faulty scrub head up/down switch, trigger switch(es), or relay	Test each and replace the failed component — see the schematic in the service manual (p. 41).

Maintenance intervals: Carbon brushes in the disk brush motors, vacuum motor and drive transaxle motor should be replaced about every 750 hours; cylindrical brush motors about every 1,000 hours. On cylindrical models, check belt tension every 100 hours: it should flex about 0.1 in (3 mm) at the midpoint under 2.5–2.7 lb (1.13–1.22 kg) of force.

Safety: Disconnect the battery cables before servicing any motor.

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Adjusting Scrub Head BrushesOperator Manual · Pages 23–25

Adjusting Scrub Head BrushesService Manual · Page 13

Adjusting Brush PatternsService Manual · Page 14

Scrub Brush CircuitService Manual · Page 41

Scrub Head Group, Disk 24 inInteractive Parts Manual

Also in the parts manual: Disk 28 in · Disk 32 in · Cylindrical 26 in · Cylindrical 32 in · Component Panel Group (breakers)

6Machine Will Not Propel

The brushes and vacuum run, but the machine will not drive. The drive system is a 24 V transaxle with its own 30 A fuse.

Possible cause	What to do
Parking brake is set	Release the parking brake lever.
Machine fault detected	Check the battery meter and go to Problem 2.
Propel motor fuse blown	Replace the 30 A fuse (never a higher rating).
Exceeded maximum incline	Avoid steep inclines and reset the key. Rated grade: scrubbing 5%, transporting 8%, ramping 19.5%.
Worn carbon brushes	Replace the transaxle motor carbon brushes. Carbon brush kit (614166)
Faulty transaxle motor or wiring	Replace the transaxle. Transaxle, 24 VDC (1021168)

Tip: If the LED bars ripple back and forth when you turn the key on, a trigger was held at start-up. Release it and cycle the key. Two fast-flashing bars point to an open propel motor circuit; three bars means a shorted or tripped drive motor.

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Battery Meter LED Fault CodesOperator Manual · Page 38

Propel Forward SystemService Manual · Page 39

BDI Diagnostic Fault IndicatorsService Manual · Page 33

Frame GroupInteractive Parts Manual

Also in the parts manual: Control Console Group

7Vacuum Motor Not Running or Poor Water Pickup

Streaks, wet floors and a squeegee that leaves water behind are the number-one complaint on any scrubber. Most of the time the cause is a clog, a leak in the vacuum path or a worn blade — not the motor.

Vacuum motor will not operate

Possible cause	What to do
Squeegee is raised off the floor	Lower the squeegee – the vacuum only runs with it down.
Discharged batteries	Charge the batteries.
Tripped vacuum motor circuit breaker	Reset the 25 A circuit breaker (B). 25 A breaker (383724)
Worn carbon brushes	Replace the vacuum motor carbon brushes. Vacuum motor brushes (1073334)
Faulty vacuum motor or wiring	Test and replace; see the vacuum fan schematic in the service manual (p. 42).

Poor water pickup

Possible cause	What to do
Recovery tank full, or excessive foam	Drain the recovery tank. Use less detergent, or a low-foam product.
Loose drain hose cap	Tighten the cap. Drain cap O-ring (1008637)
Clogged float shut-off screen in the recovery tank	Clean the screen. Float shut-off (630052)
Clogged squeegee assembly	Clean the squeegee assembly.
Worn squeegee blades	Rotate or replace the blades (see below).
Incorrect squeegee blade deflection	Adjust the blade height (see below).
Loose, clogged or damaged vacuum hose	Secure the connections, clear the debris, or replace the hose. Vacuum hose (1014026)
Recovery tank cover not in place, or damaged cover seal	Seat the cover properly; replace the seal. Lid seal (1017959)
Faulty vacuum motor / low battery charge	Recharge the batteries; if the problem remains, test the vacuum motor.

Squeegee blades: rotate, then replace

When a blade wears, rotate it end-for-end or top-to-bottom to a fresh wiping edge. Replace it when all edges are worn.
Rear blade: loosen the band clamp, remove the band, replace or rotate the blade, and refit the band.
Front blade: remove the band, loosen the four knobs, then replace or rotate the blade.
On the 28 in and 32 in squeegees the front blade has a 12/14-slot edge and a 6-slot edge. On cylindrical-brush models making sharp turns, use the 12/14-slot edge for maximum water pickup.
Deflection: the service manual shows about ½ in (12.5 mm) of blade deflection. Set it with the squeegee on a level surface by adjusting the casters (the service manual shows a 1/16 in / 2 mm reference at the caster).

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Draining and Cleaning TanksOperator Manual · Page 19

Machine SetupOperator Manual · Pages 10–13

Battery Installation & Squeegee RemovalService Manual · Page 9

Battery Maintenance & Squeegee BladesService Manual · Page 18

Squeegee Blades, Motor & FaST MaintenanceService Manual · Page 19

Vacuum Fan SystemService Manual · Page 42

Recovery Tank GroupInteractive Parts Manual

Also in the parts manual: Vacuum Motor Group · Squeegee Group, 24 in · Squeegee Group, 26/28 in · Squeegee Group, 32 in · Squeegee Group, 20 in · Squeegee Lift Group

8Little or No Solution Flow

No water on the floor means no cleaning. The problem is almost always a clog or an empty tank. Check the basics, then your solution system type — standard, FaST or ec-H2O.

Standard solution system

Possible cause	What to do
Solution tank is empty	Fill the solution tank.
Clogged solution tank filter	Drain the solution tank, remove the filter from underneath the machine, rinse out the screen and reinstall.
Discharged batteries	Charge the batteries.
Clogged solution valve	Remove the valve and clean it. Solenoid valve (1062385) · Valve repair kit (614265)
Flow control knob set too low	Adjust the solution flow control knob.
Loose screw on the control knob	Calibrate the knob and retighten the screw. Valve knob (1013442)

FaST model (FaST-PAK detergent system)

Possible cause	What to do
FaST system switch not on	Turn on the FaST system switch.
FaST-PAK supply hose not connected / kinked	Connect the supply hose; undo any kink.
Empty FaST-PAK carton	Replace the carton.
Clogged supply hose or connectors	Soak in warm water to unclog. Store the hose on the storage plug when not in use.
Clogged detergent orifice / filter screen	Replace the orifice or filter screen (see FaST System Maintenance).
Clogged solution tank filter	Drain the tank, remove the filter, clean and reinstall. In-line filter (1005302)
FaST pump fuse blown	Replace the 7.5 A fuse.
Faulty pump, FaST on/off switch, clogged inlet filter or solution system	Service-center repair; see the FaST pump schematic in the service manual (p. 44).

ec-H2O models: indicator light guide

Model	Indicator	What to do
ec-H2O NanoClean	Blinking green/red	Water conditioning cartridge has expired — replace it. A cartridge lasts roughly 12 months (heavy use) to 24 months (light use).
ec-H2O NanoClean	Red, or blinking red	ec-H2O fault detected. First check whether cleaning detergent was added to the solution tank. If so, drain the tank, add clear water and run the system until the code clears. If not, contact a service center.
ec-H2O (earlier)	Blinking red, alarm sounds	Mineral build-up in the module — run the module flush procedure (1 gal / 4 L of full-strength white or rice vinegar, about a 7-minute cycle).
ec-H2O (earlier)	Solid red	Freeze-protection antifreeze was not flushed from the module before use — flush it. Otherwise a defective module: contact a service center.
ec-H2O (earlier)	Light does not turn on / no water flow	Defective light, module or solution pump, or a clogged module — contact a service center.

Good to know: After first-time use or a cartridge change, an ec-H2O NanoClean machine automatically overrides the selected flow rate for up to 75 minutes. That is normal.

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Troubleshooting (cont.): ec-H2OOperator Manual · Page 38

Draining and Cleaning TanksOperator Manual · Page 19

Daily (cont.) & Monthly MaintenanceService Manual · Page 17

Squeegee Blades, Motor & FaST MaintenanceService Manual · Page 19

Solution Valve & Hour Meter CircuitService Manual · Page 43

FaST Pump & Hour Meter CircuitService Manual · Page 44

Solution Group, Standard ModelInteractive Parts Manual

Also in the parts manual: FaST Model · ec-H2O NanoClean Model · ec-H2O Model · Solution Tank Group

9Poor Scrubbing Performance

Streaky, uneven or weak cleaning is usually a consumable problem, not a mechanical one.

Possible cause	What to do
Debris caught in the brush	Stop and remove the debris. On cylindrical models, also clear the debris trough and idler plates.
Worn brushes or pads	Replace them. Rotate pads when worn; rotate cylindrical brushes front-to-rear every 50 hours and replace them when worn to 5/8 in (15 mm).
Incorrect brush pressure setting	Adjust the pressure setting (up to 120 lb / 54 kg available). Brush pressure gauge (1041318)
Wrong brush or pad type	Use the correct brush or pad for the floor and soil.

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Adjusting Scrub Head BrushesOperator Manual · Pages 23–25

Adjusting Scrub Head BrushesService Manual · Page 13

Adjusting Brush PatternsService Manual · Page 14

Daily Maintenance (cont.)Service Manual · Page 16

Scrub Head Group, Disk 24 inInteractive Parts Manual

Also in the parts manual: Cylindrical 26 in · Control Console Group (pressure gauge)

10Scrub Head Will Not Raise or Lower

The troubleshooting chart does not list the lift system, but the service manual includes the full raise and lower circuits — a good map for a methodical diagnosis.

Confirm the charger is unplugged, the emergency stop is released, the key is on, and the 10 A breaker is not tripped.
Check for a battery meter fault code (Problem 2) — low batteries can limit machine functions.
Use the lower and raise schematics (service pages 45 and 46) to trace the circuit: key switch, emergency stop, the up/down switch, the actuator relay and the actuator’s internal limit switch.
If the circuit tests good up to the actuator and it still will not move, replace the actuator.

Safety: Support the scrub head before working on the actuator, and disconnect the battery cables before touching any wiring.

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Speed Scrub Component Locator 3 of 4Service Manual · Page 3

Scrub Head Actuator: LowerService Manual · Page 45

Scrub Head Actuator: RaiseService Manual · Page 46

Scrubhead Lift GroupInteractive Parts Manual

Also in the parts manual: Component Panel Group

11Prevent Repairs: A Simple Maintenance Routine

Most of the problems above can be avoided. The manuals call for this routine:

When	What to do
After every use	Drain and rinse the recovery tank; clean the float shut-off screen; drain the solution tank; rotate or replace worn pads; empty the debris trough (cylindrical); wipe the squeegee blades and store the squeegee raised; recharge after 30+ minutes of use.
Weekly	Check the electrolyte level in wet (lead-acid) batteries.
Monthly	Remove and rinse the solution tank filter; inspect and clean the recovery tank cover seal (replace if damaged); lubricate all pivot points, rollers and casters with water-resistant grease; clean the parking brake clamp; check for loose nuts and bolts; check the machine for leaks.
Every 50 hours	Rotate cylindrical brushes front-to-rear.
Every 100 hours	Check cylindrical brush belt tension.
Every 200 hours	Clean battery tops, terminals and cable clamps; check for loose battery connections (the service manual also lists this in the daily routine).
Every 750 / 1,000 hours	Carbon brushes: drive, vacuum and disk brush motors at 750 h; cylindrical brush motors at 1,000 h.
Every 1,000 hours (FaST)	Replace the water filter and air filter in the FaST detergent injector.

Safety: Do not power-spray or hose down the machine — electrical malfunctions may result. Clean with an all-purpose cleaner and a damp cloth.

Click here for the manual pages