SECTION 3 - SERVICING COMPONENTS

VI. BLOWER MOTOR CENTRIFUGAL SAFETY SWITCH (PS360-SERIES)

Middleby ovens have a safety feature that prevents the burner/heating elements from activating if the blower(s) are not in operation. On PS360-series ovens, this feature is controlled by a centrifugal switch mounted inside each blower motor. If either motor is not operating, the burner/ heating elements cannot activate.

The centrifugal switch is a normally-closed (NC) limit switch mounted inside the rear of each blower motor. See Figure

49.When the motor is not running, the centrifugal switch weight holds the switch open. As the motor reaches full speed, the weight moves away from the switch permitting the contacts to close. When the switch contacts of BOTH blower motors are closed, the heat circuit is completed, allowingthe burner/heating elements to activate.

If a blower motor is not operating, the switch will not close and the circuit remains open, preventing burner/heating el- ement activation.

A.Part Number Reference - Blower Centrifugal Switch

On all PS360-series blower motors, the centrifugal switch can be replaced with switch P/N 27270-0144.

B.Troubleshooting

1.To access the switch, remove the rear motor wiring cover plates. See Figure 49.

2.When the switch is operating properly, both sides of the brown wires coming from the switch should be “hot” when the motor is at full RPM.

3.No adjustment can be made to the switch. If it is not operating properly, it must be replaced.

VII. BURNER BLOWER MOTOR CENTRIFUGAL SAFETY SWITCH (PS200-SERIES GAS, PS310, PS314, PS360, PS360WB, PS570S)

Middleby gas ovens with a 120V burner blower motor have a centrifugal safety switch that prevents burner activation if the burner blower motor is not in operation. This includes:

•Most PS360-series ovens (except PS360WB70 and PS360EWB);

•PS200-series gas ovens (except units produced with the modulating gas system);

•All Model PS570S ovens.

Ovens with a 208/240V burner blower motor use a separate air pressure safety switch to prove motor operation. See Air Pressure Safety Switch on Page 81.

The centrifugal switch is a normally-closed (NC) limit switch mounted inside each blower motor. When the motor is not running, the centrifugal switch weight holds the switch open. As the motor reaches full speed, the weight moves away from the switch permitting the contacts to close. This com- pletes the heat circuit, allowingthe burner to light.

If the burner blower motor is not operating, the switch will not close and the circuit remains open, preventing burner activation.

No adjustment can be made to the switch. If it is not oper- ating properly, the burner blower motor must be replaced.

Figure 49 - PS360-series blower motor centrifugal safety switch

Switch

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Middleby Marshall PS555, PS570, PS200, PS220, PS224 PS310 manual VI. Blower Motor Centrifugal Safety Switch PS360-SERIES
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PS224 PS310, PS220, PS555, PS200, PS360 specifications

The Middleby Marshall PS555 is a standout commercial pizza oven renowned for its performance, efficiency, and advanced technologies. Designed with the modern pizzeria in mind, the PS555 delivers exceptional cooking results while maximizing energy efficiency and throughput.

One of the key features of the PS555 is its innovative cooking technology, which incorporates both convection and radiant heat. This unique combination ensures that pizzas are cooked evenly and quickly, achieving a perfectly crispy crust and evenly melted cheese every time. The oven’s high-speed air impingement system accelerates cooking times, allowing pizzerias to serve more customers in less time without compromising quality.

The PS555 is designed with a spacious cooking chamber that can accommodate multiple pizzas simultaneously. With its ability to fit pizzas up to 18 inches in diameter, the oven is ideal for establishments with high demand. Additionally, the adjustable conveyor speed allows operators to customize the cooking time based on their specific menu items, enhancing versatility and productivity.

Energy efficiency is a hallmark of the Middleby Marshall PS555. The oven utilizes advanced insulation materials to minimize heat loss, ensuring that it operates at optimal temperatures while consuming less energy. This efficiency not only reduces operating costs but also contributes to a more sustainable kitchen environment.

User-friendly controls make it simple for operators to manage the cooking process. The PS555 features digital controls with programmable settings, enabling quick adjustments to temperature and cooking time. This ensures consistent quality across different shifts and helps maintain product standards while simplifying staff training.

Durability is another defining characteristic of the PS555. Built with high-quality materials, the oven is designed for heavy use in busy commercial kitchens. Its stainless steel construction ensures resistance to wear and tear, making it a worthwhile investment for any pizzeria.

In summary, the Middleby Marshall PS555 pizza oven is a high-performance piece of equipment that combines advanced cooking technologies, efficiency, and durability. Its ability to deliver consistently excellent results while streamlining operations makes it an essential asset for any pizza business aiming to enhance its productivity and customer satisfaction.
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