A.O. Smith GB/GW-300, 500, 750 SERIES, 650 warranty Burner System, Inputs To CCB and FCB

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the surrounding air pressure. Inspection of the boiler and vent system is necessary to insure that flue gas leakage to the surrounding area does not occur.

Inspect the external surfaces of the vent system every 3 months for corrosion and leakage. Inspect the vent terminations for corrosion and foreign matter which may be blocking the exhausting flue products. Call a qualified service agent to replace or repair any corroded or leaking parts.

A qualified service agent must inspect the internal surfaces of the vent system and the boiler at least once a year.

BURNER SYSTEM

To maintain safe operation and the greatest efficiency for the boiler, observe the burner flame through the observation port on the jacket panel, once a month for proper flame characteristics.

The burners should display the following characteristics:

Provide complete combustion of gas.

Cause rapid ignition and carry over across all burners and across the entire burner.

Give quiet operation during ignition, burning and extinction.

Cause no excessive lifting of flames from the burner ports.

If the preceding characteristics are not evident, check for accumulation of lint or other foreign material that restricts the inlet air or burner ports. Ensure there is the proper amount of air to the burner. Flame lifting from the burner is caused by too much air to the burner.

The burners must be inspected by a qualified service technician at least once a year.

DO NOT STORE COMBUSTIBLE MATERIALS, GASOLINE, OR OTHER FLAMMABLE VAPORS, LIQUIDS IN THE AREA OF THE APPLIANCE. NONCOMPLIANCE MAY RESULT IN FIRE OR EXPLOSION. DO NOT OBSTRUCT THE FLOW OF COMBUSTION OR VENTILATION AIR TO THE APPLIANCE.

CHEMICAL VAPOR CORROSION

Boiler corrosion and component failure can be caused by airborne chemical vapors. Spray can propellants, cleaning solvents, refrigerants, calcium or sodium chloride (water softener salts), waxes, and process chemicals are typical compounds that are potentially corrosive. These materials are corrosive at very low concentration levels with little or no odor to reveal their presence. Products of this sort should not be stored near the boiler. Air which is brought in contact with the boiler should not contain any of these chemicals. The boiler should be provided with air from outdoors when installed in environments having corrosive atmospheres.

CIRCULATION PUMP

Refer to the pump manufacturer's schedule of maintenance for frequency and method of lubricating the pump and motor. Inspect the pump once a month for leaky mechanical seals and/or O-rings and loose or damaged components. Contact a qualified service agent to replace or repair parts as required.

ELECTRONIC HOT SURFACE

IGNITION CONTROL BOARD

The EMC5000 control system is a fully integrated, state of the art electronic control system. It consists of sensors, output devices, a power switch, a 24vac transformer, wiring, and the following printed circuit boards:

Central Control Board (CCB).

See Figure 1A.

Flame Control Board (FCB).

See Figure 1B.

User Interface Board (UIB).

This part of the User Interface

 

Module (UIM). See Figure 3.

Power Distribution Board (PDB). See Figure 1C.

Touch Sensor Board (TSB).

This is part of the User

 

Interface Module (UIM). See

 

Figure 3.

The CCB contains circuitry for both master control and flame control for the first stage. The FCB contains circuitry for flame control on up to one additional stage. Dip switches on the CCB and FCB are used to configure the system. The UIB and TSB are included in the User Interface Module (UIM) along with a 4 line by 20-character LCD display. The PDB provides connection points for input power, the water pump, and the transformer. It also distributes power to the system and contains the system fuses.

Dual stage control is accomplished by means of an internal communication network and the FCB's. One FCB is required for each stage beyond initial first stage. The CCB also contains an external communications system to allow for connection to a PC, a modem, or an EMS system. Through this connection multiple boilers can also be linked together.

CAUTION

The internal communications cables should never be connected to the external communications connectors and vice-versa.

There are several microcontrollers used on the board. Three on the CCB, two on the FCB, and one on the UIB. These micros control the temperature and ignition control functions for the boiler. Inherent in the design are the normal operating sequences and safety features associated with a gas ignition control system. The system continuously performs various diagnostic tests to verify proper appliance and control operation. Should an unsafe condition occur, the control will shut down the burner and display a red fault light as well as indicate the cause of the fault on the display. The operating programs for the system are stored in permanent memory inside the micros. User-selectable operating parameters and a history of detected faults are stored in re-writable memory in the micros. A loss of power does not affect either of the memories.

Inputs To CCB and FCB:

Temperature Sensors:

Temperature probes (CCB - outlet and either inlet or tank is required): The CCB accepts analog temperature inputs from up to three sensors (inlet, outlet and tank).

ECO input (CCB - required):

The ECO (Energy Cut-Off) is a Hi-Limit switch, which is located inside the output probe. It is a normally closed switch that opens if the probe is exposed to a temperature higher than the trip point.

Thermostat input (CCB - optional):

This input is set up to work with an externally connected thermostat that provides a contact closure. If this input is

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Contents Series 400, 401, 402, 403, 404 14-18Lighting Instructions for the GB/W 300 through 750 models Lighting Instructions Risk of ScaldsBurner System Inputs To CCB and FCBCCB Drawing #211758 FCB Drawing #211759 PDB Drawing #211760 CCB/FCB Indicator Lamps & Fuses Line Polarity Indicator & Fuse ProtectionOutputs from CCB and FCBs IgnitersFCB Eight position Dipswitch GB/LBUIM Operating Procedures Temperature Setpoints System Control AlgorithmStages 1 and 2 will turn on in sequence from 1 to Description of CCB control states Description of FCB control states Idle StateOperating Setpoint Operating Differential SetpointConnection Diagram Drawing #211769 Page UIM Touch Switches Hard Fault Displayed Description Red LED LockoutSoft See below Other troubleshooting hints Page Page Page NEW Boiler Limited Warranty

500, 750 SERIES, 650, GB/GW-300 specifications

The A.O. Smith GB/GW-300, 650, 750 Series, and 500 represent a cutting-edge line of commercial water heaters designed to meet the diverse needs of various applications. These models are highly regarded for their advanced features, robust construction, and reliable performance, making them ideal for businesses such as restaurants, hotels, and industrial facilities.

One of the main features of the A.O. Smith GB/GW series is its high-efficiency design. These water heaters are built with advanced insulation and heat exchanger technology, which contribute to reduced energy consumption and lower operating costs. The products achieve notable energy efficiency ratings, ensuring that businesses can maintain their hot water supply without incurring excessive utility bills.

The GB/GW series also incorporates a user-friendly digital control system. This technology allows operators to monitor and adjust settings easily, providing real-time feedback on temperature and energy consumption. This level of control enhances operational efficiency and ensures hot water is always available when needed.

Another significant characteristic of the A.O. Smith GB/GW series is its durable construction. The units are designed with high-quality materials that resist corrosion and wear, extending their operational lifespan. The stainless steel tanks and heat exchangers are engineered to withstand high temperatures and pressure, making them reliable even in demanding environments.

Moreover, safety features are paramount in the design of these water heaters. The series includes multiple safety mechanisms, such as high-temperature limit switches and pressure relief valves, ensuring the safe operation of the unit at all times. This not only protects the equipment but also guarantees the safety of personnel using hot water.

The GB/GW series ranges in capacity, accommodating different sizes of operations. From the compact and efficient 300 model to the larger 650 and 750 units, the series offers flexibility to suit various demands. The 500 model strikes a balance between capacity and efficiency, making it a popular choice for medium-sized establishments.

In summary, the A.O. Smith GB/GW-300, 650, 750 Series, and 500 are exemplary choices for commercial water heating solutions. Their combination of efficiency, advanced technology, durable design, and comprehensive safety features ensures that businesses have access to reliable hot water, ultimately supporting their operational needs and enhancing service delivery.