ATO System Sequence of Operation

Prerequisites

Vat oil conditions that must be met before the Auto Top-Off (ATO) system engages are:

• Oil level status is low

• 30 Seconds or more after a cook cycle

• 60 Seconds after oil temperature has been within 10°F (6°C) below set point

• 60 Seconds after a filtration operation

• Filter prompt or Oil & Filter menu are not active

• Vat temperature probe reading greater than 250°F (121°C)

• Selector valve is in usable state

• No user oil level prompts

If any of the conditions are not met, then the ATO system will remain idle. Also, the ATO system will exit a top-off operation under any of the following conditions:

• Oil level status is full

• Cook cycle is started

• User requested filtration operation

Level Probes

Input to the ATO system is provided by the upper and lower level RTD probes which provide a resistance value to the PMU PCB for a temperature reading . The upper and lower level probe temperature readings are compared to the main temperature probe value and differences are calculated. If the upper or lower level probes are 15°F (8°C) less (cold) than the main probe then a low oil level status is provided to the F5 control system. With all other prerequisites met, the ATO system will begin its top-off routine.

• Low oil status: level probes - main probe ≤ -15°F (-8°C)

• Full oil status: level probes - main probe > -15°F (-8°C)

Selector Valve

Orientation of the selector valve to the vat being topped occurs as the first ATO action. By first rotating the selector valve to the proper vat position this allows for an open path for new oil to flow. The selector valve is a rotary valve with a fixed body and inner spool that rotates. Rotation and positioning of the selector valve inner spool is provided by a motor/encoder assembly. To rotate the selector valve spool a 24 volt DC signal is sent from the OMS PCB to the selector valve motor. As the selector valve motor rotates, a pulsing 5 volt DC encoder position signal is returned to the OMS. Once the desired selector valve position is confirmed the OMS PCB removes the 24 volt DC signal, and the motor stops rotating. The selector valve motor will rotate in either direction to achieve the desired position with shortest travel. The OMS PCB reverses 24 volt DC rotation signal polarity to change motor direction.

ATO Reservoir (JIB)

Holding new oil for vat top-off is handled by the ATO reservoir or Jug In a Box (JIB). When the ATO reservoir is depleted it can be manually replaced with a new JIB or refilled if the F5 fryer is connected to a bulk oil supply system. In the case of a bulk oil supply system, the bulk oil system's external pump supplies oil to the fryer which then fills the ATO reservoir. Oil in the ATO reservoir should always be new (fresh) and at room temperature (cold).

ATO (JIB) Pump

Moving oil from the reservoir to a vat needing top-off is performed by the ATO (JIB) pump. Line voltage AC is continually supplied to the OMS PCB for the filter pump motor and ATO pump. When the F5 control system energizes the ATO pump, an OMS PCB mounted relay closes, sending single-phase line voltage to the ATO pump. The top-off process cycles every 30 seconds during normal operation with an ATO pump energize pulse time of six (6) seconds for full vats and four (4) seconds for split vats. For the top-off cycle's remaining 20-25 seconds the F5 control system evaluates whether the attempt was successful or not. If the vat oil level probes do not indicate a full status another 30 second ATO cycle will begin.

• Single-phase line voltage AC from OMS PCB

• 30 second ATO cycle

• ATO pump energize time

  • Full vat: 6 seconds

  • Split vat: 4 seconds

• Remaining 20-25 seconds of ATO cycle for evaluation

• ATO cycle repeats if needed

Fill

Filling of the vat during top-off requires the ATO pump to be energized to move oil from the reservoir. Oil from the ATO pump passes through a one-way return check valve before entering the vat. The return check valve requires an oil pressure of 2 PSI (138 mbar) to open and allow oil flow. Otherwise, the return check valve remains closed to prevent oil back flow through the fryer plumbing. The F5 control system detects a topped-off vat by sensing temperature readings from the upper and lower level RTD probes and the PMU PCB comparing them to the main probe readings.

• Return check valve requires 2 PSI (138 mbar)

• Increased upper and lower RTD probe readings compared to main probe indicate filled vat to the PMU PCB

  • Low oil status: level probes - main probe ≤ -15°F (-8°C)

  • Full oil status: level probes - main probe > -15°F (-8°C)

  • PMU PCB sends vat full CAN messge to OMS PCB

• OMS PCB ATO pump motor relay opens stopping single-phase line voltage