Stero Dishwasher Troubleshooting

/ Commercial Dishwashers, Troubleshooting / July 30

Stero Dishwasher Troubleshooting-Stero Dishwasher Logo

Stero manufactures some of the best warewashing equipment in the foodservice industry. That’s why many commercial kitchens rely on them to keep everything from dishes to glassware looking spotless. In the rare case one of their durable machines aren’t working properly, refer to the tips below for troubleshooting a Stero dishwasher.

Troubleshooting by Model:


Conveyor Type Dishwashers

Below are troubleshooting tips for select Stero SCT, STW, SCX and ER conveyor models.

Won’t Start



  • Tripped circuit breaker – See if the circuit breaker tripped and reset accordingly.

  • Safety switch “OFF” – If the safety switch is off, switch it to the “ON” position.


Won’t Fill or Hold Water



  • Open drain valve – If the drain valve is open, close it.

  • Drain valve won’t closing – Check if there are any food particle or items caught in the valve seat.


Won’t Wash Properly



  • Clogged spray manifolds – Remove the spray manifolds and clean them properly. Use the owner’s manual for the appropriate cleaning procedure.

  • Empty detergent container – Contact your detergent provider to reload the machine.

  • Low water levels – If the water level in the tank is low, let it refill. If the problem persists, contact an authorized service agent for help.


Won’t Rinse Properly



  • Clogged final rinse sprayers – Remove the final rinse sprayers and clean them. Make sure to follow the owner’s manual for proper cleaning instructions.

  • Empty rinse-dry container – Contact your detergent provider to reload the machine.


Won’t Come to Temperature



  • Final rinse not coming to temperature – If the final rinse doesn’t come to temperature, contact an authorized service agent to correct the issue.

  • Tripped circuit breaker (electric tank heat) – Check if the circuit breaker is tripped and needs to be reset.

  • Tank HEAT switch is off (electric tank heat) – Press the tank’s “HEAT” button so it’s activated. Wait about 15-30 minutes for the machine to reach its operating temperature.

  • Closed steam supply valve (steam tank heat) – If the steam supply valve is closed, open it.

  • Closed steam return valve (steam tank heat) – See if the steam return is closed. Open it accordingly.


Dish Racks Won’t Work Properly



  • Rack ladders are broken or rungs worn out – Check if the dish rack ladders are broken or the rungs are worn out. If so, replace the racks.

  • Table limit switch in the up position – Some models are equipped with a table limit switch. If the switch in the up position, reset it.


Pump Motor Starts Then Stops

If the pump motor stops shortly after startup, see if the spray manifolds are clogged. Remove manifolds and clean them following the cleaning instructions in the owner’s manual. If the problem continues, contact an authorized service agent to remedy it.

Shuts Off After Running Temporarily

If the machine runs for a few minutes but shuts off, check if the shutdown timer’s settings are incorrect. Make sure to contact an authorized service agent to help correct the issue.

Door Type Dishwashers

Below are troubleshooting tips for select Stero SD door models.

Won’t Operate



  • Machine turned off – See if the machine is turned off. If so, plug in the power cord and turn it on.

  • Blown fuse or tripped circuit breaker – Check for a blown fuse or tripped circuit breaker at the power supply.

  • Low water tank level – If the water level in the tank is low, give it time to refill. If the problem continues, contact an authorized service agent for assistance.


Dishes Aren’t Clean



  • Insufficient wash water – Make sure there isn’t an obstruction by the drain. This prevents the drain from closing and doesn’t provide sufficient water when washing.

  • Damaged or worn drain O-ring – Check if the drain O-ring is worn out or torn. If so, replace it.

  • Low water pressure – Disconnect power to the dishwasher and drain tank. Look for an obstruction at the pump’s intake. This can cause a drop in pressure.

  • Improper water temperature – If the water temperature is incorrect, contact an authorized service agent to adjust or repair.

  • Improper detergent dispensing – If the detergent isn’t dispensing correctly, contact detergent provider for help resolving the issue.

  • Clogged detergent dispenser – See if the dispenser is clogged and remove any obstruction.

  • Large buildups of mineral deposits – Check the wash and rinse system for large buildups of mineral deposits. Refer to the owner’s manual for diliming instructions.

  • Broken wash and rinse arms – Make sure the wash and rinse arms are rotating properly. If not, they’ll need to be replaced.

  • Obstructed wash arms – Clean the wash arms if they’re obstructed or not turning. Follow the cleaning procedure in the owner’s manual.

  • Insufficient water supply to the pump – If there isn’t adequate water supplied to the pump, check for clogged strainers. Clean them according to the guidelines in the owner’s manual.

  • Dishes are too dirty – Be sure to scrape soiled dishes before loading them into the dishwasher. Too many food remnants can prevent dishes from being cleaned thoroughly.

  • Rack loaded incorrectly – Check the instructions in the owner’s manual for proper procedures for loading the dish rack.

  • Water supply is off – See if the water supply was turned off. If so, turn it on.


Spotting on Dishes, Glassware & Silverware



  • Racks loaded incorrectly – Double check that what’s being cleaned is loaded properly.

  • Improper rinse temperature or pressure – Make sure the rinse water temperature or rinse pressure are correct. Check the owner’s manual for proper settings.

  • Low water pressure – Disconnect power to the dishwasher and drain tank. An obstruction at the pump’s intake can cause a drop in pressure.

  • Water is too hard – If the water is excessively hard, the facility might need a water softener.

  • Incorrect detergent or rinse additive – Double check the owner’s manual to see if the correct detergent or rinse additive for the water type.

  • Incorrect concentration of detergent, rinse additive or sanitizer – Refer to the owner’s manual for the correct concentration of detergent, rinse additive or sanitizer.

  • Dishes are too dirty – Soiled dishes should be scraped before loading them into the dishwasher. Too many food remnants can prevent dishes from being cleaned thoroughly.


Rinsing Poor or Rinse Temperature Too Low



  • Dirty line strainer – A dirty line strainer can decrease the flow of water into the machine. Turn off the water supply and remove the strainer cap. Then, withdraw and clean the strainer screen before reassembling.

  • Extreme buildup of mineral deposits – Check the wash and rinse system for large buildups of mineral deposits. Refer to the owner’s manual for diliming instructions.

  • Low water temperature to booster – If the water temperature to the booster is below 110 degrees Fahrenheit. The machine should extend the wash time automatically until the booster heats up. Contact an authorized service agent if the issue persists.

  • Low supply line pressure – See if the pressure form the supply line is low.


Valve Leaking



  • Materials in the valve – Check for substances in the valve. This is common after installation when metal shavings and pipe compound get into the valve seat. Shut off the supply line to clean the valve.

  • Solenoid valve won’t open or close – If the solenoid valve isn’t opening or closing, contact an authorized service agent to repair the issue.


Water Dribbling from Lower Rinse Arm



  • Standard dribbling (electric booster) – Models with an electric booster normally drip from the lower rinse arm during the water heating. This happens once between cycles.

  • Continuous dribbling or leaks – If water consistently dribbles or leaks from rinse arms, it could be a leaking valve. See the “Valve Leaking” section above.


Comments are closed.