Fault Diagnosis: Troubleshooting Soft Serve Machines, Ice Makers and Freezers

The power switch is not turned on.

Turn on the power switch.

Input power line does not meet device requirements.

Have a licensed electrician confirm that the circuit matches the voltage, amperage and breaker size on the machine's rating plate, and that the machine is on a dedicated circuit.

Internal wiring is damaged (for example by pests) or has come loose.

Have a licensed electrician repair or secure the wiring.

The control board is faulty.

Contact Smartool support with the model and serial number.

The supply circuit or breaker is undersized for the machine.

Have a licensed electrician upgrade the circuit to match the rating plate.

Running on an undersized circuit can seriously damage the machine.

Internal wiring is damaged (for example by pests).

Have a licensed electrician replace or repair the wiring.

Hardness setting is too high, causing excessive load.

Adjust the hardness setting downwards.

Unstable voltage has damaged circuit components.

Have a licensed electrician inspect the supply and the damaged components.

Short circuit in the motor, circuit board, or compressor.

Contact Smartool support with the model and serial number.

The machine casing is not grounded.

Unplug the machine and have a licensed electrician confirm the outlet and machine are properly grounded. Do not use the machine until this is fixed.

The D-shaped seals on the draw valve are not seated correctly.

Check that both D-shaped seals on the draw valve sit fully in their grooves.

O-ring on the beater rod is damaged.

Remove the beater rod and check if the seals at both ends are worn. Replace if worn.

The freezer door (dispensing head) knobs are not tightened.

Tighten the four knobs evenly, in a diagonal pattern.

Incorrect disassembly or installation of the beater rod, causing damage to the seal.

Pull the beater straight out when removing it. When reinstalling, apply food-grade lubricant around the valve stem seal and push it straight in. Do not clean seals with sharp tools.

Loud noise during the 'Clean' cycle.

Noise is louder while cleaning and drops once mix is added. Also check that the machine stands level and that the side panel screws are tight.

Motor belt is too loose or too tight.

Have a technician adjust or replace it.

Reducer needs lubrication.

Lubricate the gear reducer every three months of use.

Abnormal noise from the motor or reduction gear.

Contact Smartool support with the model and serial number.

Loud noise during refrigeration.

Noise is louder when mix is low and drops once you top up. If the hardness setting is very high, lower it.

The freezer door (dispensing head) knobs are not tightened.

Tighten the four knobs evenly, in a diagonal pattern.

Rear seal of the agitator is worn.

Replace the rear seal.

Rear sealing cover of the evaporator is damaged.

Check how the machine is being cleaned and reassembled. Contact Smartool support with the model and serial number.

Dispensing too frequently.

Wait until the display reads at least 90 (of 99) before dispensing.

Your sales volume exceeds the machine's output.

Contact us about a higher-output model or a second machine.

Issue with the ice cream mix recipe.

Adjust the mix ratio (water to powder).

The machine cannot release heat.

Ensure proper ventilation on both sides of the machine, with at least 3 ft (1 m) of clearance.

Hardness setting is too low.

Increase the hardness setting.

The supply voltage is unstable.

Have a licensed electrician check that the supply voltage stays within the range on the machine's rating plate. Add a voltage stabilizer if needed.

Belt is loose or worn.

Adjust or replace the belt.

Refrigeration system failure (refrigerant leak or compressor fault).

Contact Smartool support with the model and serial number.

Not enough mix in the hopper.

Keep the hopper at least two-thirds full.

Low-quality mix.

Switch to a better-quality soft serve mix.

Incorrect mixing ratio.

Slightly reduce the proportion of water.

Not dispensed for a long time.

Dispense some ice cream periodically.

Hardness setting is too low.

Slightly increase the hardness setting.

The beater is worn.

Replace the beater. Contact Smartool support with the model and serial number.

Mix has been agitated for too long.

If there are long gaps between servings, switch the machine to standby.

The draw handle is not fully pulled down.

The machine only dispenses when the handle is fully down. If it still will not start, the dispensing switch may need checking.

The first serving after a long stop is soft.

This is normal after the machine has been idle. Shorten the stop time if it bothers you.

Hardness setting is too high or too low.

Adjust the setting appropriately.

Stop time is set too long.

Adjust the stop time setting.

Faulty dispensing switch.

Replace the dispensing switch. Contact Smartool support with the model and serial number.

Water was left in the cylinder for a long time and the beater has swollen.

Do not force it. Contact Smartool support with the model and serial number.

The 'Clean' cycle ran for a long time with no water or mix, and friction heat swelled the beater.

Do not force it. Contact Smartool support with the model and serial number.

The hopper light flashes and the alarm sounds.

Add mix to the hopper right away.

There is mix in the hopper but the alarm continues.

The mix may be foamy and not flowing into the cylinder; stir it. If mix is flowing, run 'Clean' for 5 minutes.

On first start-up the low-mix alarm sounds before the display reaches 99.

Contact Smartool support with the model and serial number. We will walk you through the settings.

Speed sensor fault.

Check that the magnet is on the pulley, then adjust or replace the speed sensor.

The buzzer sounds continuously and the machine stops.

Check whether the speed sensor has moved or its wire has come loose.

The pulley wobbles.

Tighten the pulley set screw. If the gear reducer is damaged, contact Smartool support.

Low mix in the hopper.

Add mix and restart the machine.

The beater is slipping.

The mix has too much water, or the hardness setting is too high. Adjust either one.

High ambient temperature or blocked air vents.

Improve ventilation and clear obstructions from air vents.

Poor refrigeration.

Check the condenser for dirt and that airflow is clear. A low refrigerant charge needs a technician. Contact Smartool support with the model and serial number.

Belt is worn and slipping.

Adjust belt tension or select a reasonable hardness setting.

The freezing cylinder has frozen solid.

Use less water in the mix or lower the hardness setting. If it keeps happening, contact Smartool support.

The gear reducer is damaged (one side turns, the other does not).

Contact Smartool support with the model and serial number.

Motor won't turn, runs slow, or spins freely.

Contact Smartool support with the model and serial number.

Sensor failure or loose sensor connection.

Contact Smartool support with the model and serial number.

The supply voltage is unstable.

Have a licensed electrician check that the supply voltage stays within the range on the machine's rating plate. Add a voltage stabilizer if needed.

The beater has swollen and is binding in the cylinder.

Do not force it out. Contact Smartool support with the model and serial number.

The motor runs slowly.

The motor may be failing. Contact Smartool support with the model and serial number.

The drive belt is worn.

Replace the drive belt.

Micro switch fault.

Check whether the dispensing plate has returned to position, or the micro switch is damaged.

Control board fault.

The control board needs replacing. Contact Smartool support with the model and serial number.

Improper hardness setting.

Lower the hardness setting slightly.

The mix recipe is too rich.

Add slightly more water to the mix.

High ambient temperature, poor ventilation, or blocked vents.

Ensure the machine is in a well-ventilated area and clear obstructions.

Unstable voltage or insufficient power capacity.

Have a licensed electrician check that the supply voltage stays within the range on the machine's rating plate.

The cylinder frosts poorly, or the suction line has no frost when empty.

This usually means a refrigerant leak. A certified refrigeration technician must recover and weigh in the charge; refrigerant may not be vented. Contact Smartool support with the model and serial number.

Compressor high-pressure alarm.

The condenser is dirty or the condenser fan has failed. Clean the condenser; a failed fan needs replacing.

Supply voltage is too high.

Have a licensed electrician check that the supply voltage stays within the range on the machine's rating plate. Add a voltage stabilizer if needed.

Supply voltage is too low.

Have a licensed electrician check that the supply voltage stays within the range on the machine's rating plate. Add a voltage stabilizer if needed.

The hopper ran empty and the cylinder dropped below -31°F (-35°C), or a sensor terminal is loose.

Refill the hopper and restart. If the alarm returns with mix in the hopper, contact Smartool support with the model and serial number.

The temperature sensor is shorted, or the cylinder is above 140°F (60°C).

Make sure the machine has not been left in heat mode or a hot room. If the alarm stays on, contact Smartool support with the model and serial number.

No power.

Check that the power switch is on and the outlet is live.

A blown fuse, transformer or main board fault needs a technician.

No water connection.

Check the water supply valve.

The ice curtain (deflector) is held open.

The curtain must swing freely and close.

High-pressure protection has tripped.

Check whether the room is too hot, the condenser filter is dirty, or the condenser fan motor has failed.

A failed fan motor needs a technician.

The bin is full, or the ice curtain is stuck open.

Check that the curtain swings freely, the bin-full switch is in place, and the curtain and its magnet have not come off.

The evaporator (ice grid) is dirty.

Clean and sanitize the evaporator.

Ice maker is not level.

Level the ice maker.

Ambient temperature is too low.

Ambient temperature must be at least 41°F (5°C).

Water valve, refrigerant or control board fault.

These need diagnosis by a technician. Contact Smartool support with the model and serial number.

Ice thickness is not adjusted correctly.

Adjust the ice thickness setting.

Water level in the trough is too low.

Check the water level or look for leaks.

The water inlet valve is not opening.

Check the water inlet valve. Contact Smartool support with the model and serial number.

Insufficient water pressure.

Water pressure must be between 19 and 80 psi (0.13–0.55 MPa).

The water line is blocked.

Check the water lines and fittings for debris.

Water flow from the distributor is uneven.

Adjust or clean the water distributor.

Condenser is dirty.

Clean the condenser every 1–2 months.

High ambient temperature or obstructed airflow.

Ambient temperature should not exceed 104°F (40°C). Remove obstructions to ensure ventilation.

Water trough is leaking.

Replace the water trough.

The water valve leaks slightly, or there is a small refrigerant leak.

These need diagnosis by a technician. Contact Smartool support with the model and serial number.

Ice thickness is not adjusted correctly.

Adjust the ice thickness setting.

Several cycles ran without a harvest.

Clean the evaporator so the ice releases.

The ice curtain is not working.

Check that the curtain and its magnet have not come off and that the curtain swings freely.

Bin-full switch fault.

Check whether the switch has come loose or is broken.

The water trough is low or empty.

Check the water level, look for leaks and confirm the water supply.

The water pump is not running.

Check that the pump wiring to the main board is secure, and clean any debris or scale out of the pump.

No water from the tap, or inlet hose is disconnected.

Check the water supply valve and inlet hose.

The water inlet valve is faulty.

Check whether the valve leaks or fails to open.

The float switch is faulty.

Check whether the float is stuck and free it. A broken float needs replacing.

The water trough leaks.

Check the trough drain plug and the float valve.

Water splashes out of the distributor.

Reposition the water distributor.

The drain is clogged.

Clear the drain.

The drain line is routed incorrectly.

The end of the drain line must be level with or below the drain inlet, with no upward loops.

Low voltage.

Have a licensed electrician check that the supply voltage stays within the range on the machine's rating plate.

The start relay, overload protector or capacitor has failed.

These parts need testing and replacement by a technician. Contact Smartool support with the model and serial number.

Compressor fault.

The compressor needs testing by a technician. Contact Smartool support with the model and serial number.

Control board fault.

The control board needs testing or replacement. Contact Smartool support with the model and serial number.

The evaporator is mounted at an angle.

Re-level the evaporator.

Low refrigerant charge.

Usually caused by a leak. A certified refrigeration technician must recover and weigh in the charge; refrigerant may not be vented. Contact Smartool support with the model and serial number.

Refrigerant overcharge.

A certified refrigeration technician must recover and weigh in the charge; refrigerant may not be vented. Contact Smartool support with the model and serial number.

Refrigerant leak.

The leak must be found and repaired, the system evacuated and recharged. A certified refrigeration technician must recover and weigh in the charge; refrigerant may not be vented. Contact Smartool support with the model and serial number.

The water valve does not close.

The valve needs replacing. Contact Smartool support with the model and serial number.

A blockage in the refrigeration system.

The system needs repair by a technician. Contact Smartool support with the model and serial number.

The ice thickness probe is faulty or set too close.

Adjust the probe gap; replace the probe if it is faulty.

Control board fault.

Check that all connectors on the control board are secure and look for visible damage. Contact Smartool support with the model and serial number.

The magnetic (curtain) switch is not working.

Check that the switch returns to position and adjust it. A broken switch needs replacing.

The ice curtain does not return to position.

Adjust the curtain so it closes fully.

Poor contact or faulty thermostat.

Check wiring or replace the thermostat.

Poor contact or faulty fan.

Check wiring or replace the fan.

Supply voltage is too low.

Have a licensed electrician check that the supply voltage stays within the range on the machine's rating plate.

Ice or debris is blocking the refrigeration system.

The filter drier or capillary tube needs replacing by a technician. Contact Smartool support with the model and serial number.

The compressor is not running: wiring fault or tripped overload protector.

Check the wiring and supply voltage. If those are fine, contact Smartool support with the model and serial number.

Refrigerant leak.

The leak must be found and repaired, the system evacuated and recharged. A certified refrigeration technician must recover and weigh in the charge; refrigerant may not be vented.

The system was not fully evacuated.

The system needs evacuating and recharging. A certified refrigeration technician must recover and weigh in the charge; refrigerant may not be vented.

The fan has failed, is miswired or is installed backwards.

Test or replace the fan.

Refrigerant overcharge.

A certified refrigeration technician must recover and weigh in the charge; refrigerant may not be vented.

Low refrigerant charge.

A certified refrigeration technician must recover and weigh in the charge; refrigerant may not be vented.

The thermostat cuts out too early.

Adjust the thermostat setting and clear any ice around the thermostat probe.

Compressor capacity has dropped.

The compressor needs replacing. Contact Smartool support with the model and serial number.

The room is too hot.

Keep the area around the freezer well ventilated.

The condenser is dirty.

Clean the condenser once a month.

Too much product was loaded at once.

Load in smaller batches and keep product at least 4 in (10 cm) away from the thermostat probe.

Cold air leaks past the door gasket.

Warm and reshape the gasket so it seals, or replace it. Gaskets harden with age.

Frost buildup inside is thicker than 0.2 in (5 mm).

Clean and defrost regularly.

The room is too hot.

Keep the area around the freezer well ventilated.

The condenser is dirty.

Clean the condenser.

Thermostat failure.

Check the thermostat.

Cold air leaks past the door gasket.

Warm and reshape the gasket so it seals, or replace it.

The fan is not running.

Check the evaporator and condenser fans.

Low refrigerant charge or a small leak.

The leak needs finding and repairing. A certified refrigeration technician must recover and weigh in the charge; refrigerant may not be vented.

Thermostat failure.

Replace the thermostat.

Supply voltage is too low.

Have a licensed electrician check that the supply voltage stays within the range on the machine's rating plate.

The overload protector, start relay or capacitor has failed.

These parts need testing and replacement by a technician.

Compressor motor failure or seizure.

The compressor needs replacing. Contact Smartool support with the model and serial number.

Supply voltage is too low.

Have a licensed electrician check that the supply voltage stays within the range on the machine's rating plate.

The condenser is dirty.

Clean the condenser regularly.

Poor ventilation.

Keep the area around the unit well ventilated.

Fan not working.

Check if the fan blade is stuck or if the fan is broken.

Refrigerant overcharge.

A certified refrigeration technician must recover and weigh in the charge; refrigerant may not be vented.

The overload protector, start relay or capacitor is failing.

These parts need testing and replacement by a technician.

The freezer is not level.

Level the freezer.

Fan noise.

Tighten mounting screws, adjust fan blade, or replace the fan.

Compressor noise.

Tighten mounting screws or replace the compressor.

A copper line touches another part and vibrates.

Reposition the line so it does not touch.

A fan blade rubs against the housing or condenser fins.

Re-align the fan.

The probe wire is broken or disconnected.

Reconnect the probe wire if it has come loose.

The probe wire is shorted.

Replace the probe or the thermostat.

The temperature probe reads above 122°F (50°C), which is rare.

Let hot product cool to room temperature before loading it.

A damaged probe wire gives false readings.

Replace the probe wire.

Thermostat control board fault.

Replace the thermostat.

Frost on the left side is so thick the compressor cycles off.

Defrost the freezer regularly.