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Bryant 558J manual Sequence of Operation, General, Electro-mechanical units with no economizer

Models: 558J

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SEQUENCE OF OPERATION

558J

General

The sequence below describes the sequence of operation for an electro-mechanical unit with and without a factory installed EconoMi$er IV (called “economizer” in this sequence). For information regarding a direct digital controller, see the start-up, operations, and troubleshooting manual for the applicable controller.

Electro-mechanical units with no economizer

Cooling —

When the thermostat calls for cooling, terminals G and Y1 are energized. As a result, the indoor-fan contactor (IFC) and the compressor contactor (C1) are energized, causing the indoor-an motor (IFM), compressor #1, and outdoor fan to start. If the unit has 2 stages of cooling, the thermostat will additionally energize Y2. The Y2 signal will energize compressor contactor #2 (C2), causing compressor #2 to start. Regardless of the number of stages, the outdoor-an motor runs continuously while unit is cooling.

Heating

NOTE: The 558J is sold as cooling only. If electric heaters are required, use only factory-approved electric heaters. They will operate as described below.

Units have either 1 or 2 stages of electric heat. When the thermostat calls for heating, power is applied to the W1 terminal at the unit. The unit control will energize the indoor fan contactor and the first stage of electric heat. On units with two-stage heating, when additional heating is required, the second stage of electric heat (if equipped) will be energized when power is applied at the W2 terminal on the unit.

Electro-mechanical units with an economizer

Cooling —

When free cooling is not available, the compressors will be controlled by the zone thermostat. When free cooling is available, the outdoor-air damper is modulated by the EconoMi$er IV control to provide a 50_F (10_C) to 55_F (13_C) mixed-air temperature into the zone. As the mixed air temperature fluctuates above 55_F (13_C) or below 50_F (10_C) dampers will be modulated (open or close) to bring the mixed-air temperature back within control. If mechanical cooling is utilized with free cooling, the outdoor-air damper will maintain its current position at the time the compressor is started. If the increase in cooling capacity causes the mixed-air temperature to drop below 45_F (7_C), then the outdoor-air damper position will be decreased to the minimum position. If the mixed-air temperature continues to fall, the outdoor-air damper will close. Control returns to normal once the mixed-air temperature rises above 48_F (9_C). The power exhaust fans will be energized and de-energized, if installed, as the outdoor-air damper opens and closes.

If field-installed accessory CO2 sensors are connected to the EconoMi$er IV control, a demand controlled ventilation strategy will begin to operate. As the CO2 level in the zone increases above the CO2 set point, the minimum position of the damper will be increased proportionally. As the CO2 level decreases because of the increase in fresh air, the outdoor-air damper will be proportionally closed. For EconoMi$er IV operation, there must be a thermostat call for the fan (G). If the unit is occupied and the fan is on, the damper will operate at minimum position. Otherwise, the damper will be closed.

When the EconoMi$er IV control is in the occupied mode and a call for cooling exists (Y1 on the thermostat), the control will first check for indoor fan operation. If the fan is not on, then cooling will not be activated. If the fan is on, then the control will open the EconoMi$er IV damper to the minimum position.

On the initial power to the EconoMi$er IV control, it will take the damper up to 2 1/2 minutes before it begins to position itself. After the initial power-up, further changes in damper position can take up to 30 seconds to initiate. Damper movement from full closed to full open (or vice versa) will take between 1 1/2 and 2 1/2 minutes. If free cooling can be used as determined from the appropriate changeover command (switch, dry bulb, enthalpy curve, differential dry bulb, or differential enthalpy), then the control will modulate the dampers open to maintain the mixed-air temperature set point at 50_F (10_C) to 55_F (13_C). If there is a further demand for cooling (cooling second stage - Y2 is energized), then the control will bring on compressor stage 1 to maintain the mixed-air temperature set point. The EconoMi$er IV damper will be open at maximum position. EconoMi$er IV operation is limited to a single compressor.

Heating

The sequence of operation for the heating is the same as an electromechanical unit with no economizer. The only difference is how the economizer acts. The economizer will stay at the Economizer Minimum Position while the evaporator fan is operating. The outdoor-air damper is closed when the indoor fan is not operating.

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Bryant 558J manual Sequence of Operation, General, Electro-mechanical units with no economizer
Page 45 Page 47

558J specifications

The Bryant 558J is a high-efficiency air conditioning unit that provides outstanding comfort and performance for residential spaces. Engineered with contemporary technology, this HVAC system showcases a blend of innovative features designed to enhance user experience while promoting energy efficiency.

One of the main features of the Bryant 558J is its high Seasonal Energy Efficiency Ratio (SEER) rating, which ensures optimal energy savings while providing consistent cooling throughout the warmer months. This model boasts an impressive SEER that positions it among the top performers in its category, making it an excellent choice for environmentally-conscious homeowners looking to reduce their energy consumption.

The Bryant 558J utilizes advanced variable-speed compressor technology. This means it can adjust its cooling output dynamically based on indoor temperature requirements, which results in improved temperature consistency and quieter operation. Unlike single-speed systems that can be noisy during operation, the variable-speed compressor provides a more tranquil living environment, as it can run at lower speeds for extended periods.

Additionally, the unit is equipped with a durable, all-weather cabinet designed to resist corrosion and withstand the elements, ensuring longevity and reliability. The unit's aesthetic design also allows it to blend seamlessly into most outdoor settings, enhancing curb appeal without compromising functionality.

In terms of installation and maintenance, the Bryant 558J offers user-friendly features. Its compact design makes it easy to install in tight spaces, while the easy-access panel allows for straightforward maintenance and servicing, reducing downtime and improving overall efficiency.

The unit is compatible with smart thermostats, allowing homeowners to integrate modern technology into their HVAC systems. This compatibility empowers users to control their home environment remotely, monitor energy usage, and create personalized schedules that align with their lifestyles.

Furthermore, the Bryant 558J comes with a comprehensive warranty, offering peace of mind to residents investing in a cooling solution. This level of backing evidences the manufacturer's commitment to quality and customer satisfaction.

In summary, the Bryant 558J stands out as a premier air conditioning solution characterized by its high efficiency, variable-speed technology, durable construction, and modern compatibility. Whether for new installations or replacements, this model exemplifies the perfect balance of comfort, reliability, and energy savings, making it a worthwhile investment for any homeowner.