Bryant manual Controls, Operating Sequence for 581B036-072 Units

Page 58

CONTROLS

OPERATING SEQUENCE FOR 581B036-072 UNITS

Cooling, Units Without Economizer — When thermostat calls for cooling, terminals G and Y1 and the compressor contactor

(C)are energized. The indoor (evaporator) fan motor (IFM), compressor, and outdoor (condenser) fan motor (OFM) start. The OFM runs continuously while the unit is in cooling. When the thermostat is satisfied, C is deenergized and the compres- sor and OFM shut off. After a 30-second delay, the IFM shuts off. If the thermostat fan selector switch is in the ON position, the evaporator motor will run continuously.

Cooling, Units With Durablade Economizer — When the outdoor-air temperature is above the outdoor-air temperature (OAT) setting and the room thermostat calls for cooling, the compressor contactor is energized to start the compressor and outdoor (condenser) fan motor (OFM). The indoor (evaporator) fan motor (IFM) is energized and the economizer damper moves to the minimum position. After the thermostat is satis- fied, the damper moves to the fully closed position when IFM is deenergized.

When the outdoor-air temperature is below the OAT setting and the thermostat calls for Y1 and G, the economizer damper moves to the minimum position when the evaporator fan starts. The first stage of cooling is provided by the economizer. If the supply-air temperature is above 57 F, a switch on the supply-air thermostat is closed between the T2 terminal and the 24 vac terminal. This causes the damper to continue to modulate open until the supply-air temperature falls below 55 F or the damper reaches the fully open position.

When the supply-air temperature is between 55 F and 52 F, the supply-air thermostat has open switches between the T2 and 24 vac terminals and between the T1 and 24 vac terminals. This causes the economizer damper to remain in an intermediate open position.

If the supply-air temperature falls below 52 F, a switch on the supply-air thermostat is closed between the T1 terminal and the 24 vac terminal. This causes the damper to modulate closed until the supply-air temperature rises above 55 F or the damper reaches the minimum position.

When the supply-air temperature is between 55 F and 57 F, the supply-air thermostat has open switches between the T2 and 24 vac terminals. This causes the economizer damper to remain in an intermediate open position.

If the outdoor air alone cannot satisfy the cooling requirements of the conditioned space, economizer cooling is integrated with mechanical cooling, providing second stage cooling. The com- pressor and condenser fan will be energized and the position of the economizer damper will be determined by the supply-air temperature.

When the second stage of cooling is satisfied, the compressor and condenser-fan motor will be deenergized. The damper position will be determined by the supply-air temperature.

When the first stage of cooling is satisfied, the IFM shuts off after a 30-second delay. The damper then moves to fully closed position.

Cooling, Units With EconoMi$er — When the outdoor-air temperature (OAT) is above the ECON SP set point and the room thermostat calls for Stage 1 cooling (R to G +Y1), the indoor-fan motor (IFM) is energized and the EconoMi$er damper modulates to minimum position. The compressor con- tactor is energized starting the compressor and outdoor-fan motor (OFM). After the thermostat is satisfied, the damper mod- ulates to the fully closed position when the IFM is deenergized.

When the OAT is below the ECON SP set point and the room thermostat calls for Stage 1 cooling (R to G + Y1), the EconoMi$er modulates to the minimum position when the IFM is energized. The EconoMi$er provides Stage 1 of cooling by modulating the return and outdoor air dampers to maintain a 55 F supply air set point. If the supply-air temperature (SAT) is

greater than 57 F, the EconoMi$er modulates open, allowing a greater amount of outdoor air to enter the unit. If the SAT drops below 53 F, the outdoor-air damper modules closed to reduce the amount of outdoor air. When the SAT is between 53 and 57 F, the EconoMi$er maintains its position.

Heating, Units Without Economizer — When the thermostat calls for heating, terminal W1 is energized. The induced-draft motor is energized and the burner ignition sequence begins. The indoor (evaporator) fan motor (IFM) is energized 45 sec- onds after a flame is ignited. On units equipped for two stages of heat, when additional heat is needed, W2 is energized and the high-fire solenoid on the main gas valve (MGV) is ener- gized. When the thermostat is satisfied and W1 is deenergized, the IFM stops after a 45-secondtime-off delay.

Heating, Units With Economizer or Two-Position Damper — When the thermostat calls for heating, terminal W1 is ener- gized. The induced-draft motor is energized and the burner igni- tion sequence begins. The indoor (evaporator) fan motor (IFM) is energized 45 seconds after a flame is ignited and the damper moves to the minimum position. If the accessory two-position damper is used, the outdoor-air damper opens to the minimum position whenever the evaporator fan runs. On units equipped for two stages of heat, when additional heat is needed, W2 is energized and the high-fire solenoid on the main gas valve (MGV) is energized. When the thermostat is satisfied and W1 is deenergized, the IFM stops after a 45-secondtime-off delay. The economizer damper then moves to the fully closed position. When using continuous fan, the damper will remain in the mini- mum position.

OPERATING SEQUENCE FOR 581B090-150 UNITS

Cooling, Units Without Economizer — When thermostat calls for cooling, terminals G and Y1 are energized. The indoor (evaporator) fan contactor (IFC) and compressor contactor no. 1 (C1) are energized, and evaporator-fan motor, compressor no. 1, and condenser fans start. The condenser-fan motors run continuously while unit is cooling. For units with 2 stages of cooling, if the thermostat calls for a second stage of cooling by energizing Y2, compressor contactor no. 2 (C2) is energized and compressor no. 2 starts.

When the thermostat is satisfied, C1 and C2 are deenergized and the compressors and outdoor (condenser) fan motors (OFM) shut off. After a 30-second delay, the indoor (evaporator) fan motor (IFM) shuts off. If the thermostat fan selector switch is in the ON position, the evaporator motors will run continuously.

Cooling, Units With Durablade Economizer — When the outdoor-air temperature (OAT) is above the OAT setting and the room thermostat calls for cooling, the compressor contactor no. 1 is energized to start compressor no. 1 and outdoor (con- denser) fan motors (OFM). The indoor (evaporator) fan motor (IFM) is energized and the economizer damper moves to the minimum position. Upon a further call for cooling, compressor contactor no. 2 will be energized, starting compressor no. 2. After the thermostat is satisfied and the IFM is deenergized, the damper moves to the fully closed position.

When the outdoor-air temperature is below the OAT setting and the thermostat calls for Y1 and G, the economizer damper moves to the minimum position when the evaporator fan starts. The first stage of cooling is provided by the economizer. If the supply-air temperature is above 57 F, a switch on the supply-air thermostat is closed between the T2 terminal and the 24 vac terminal. This causes the damper to continue to modulate open until the supply-air temperature falls below 55 F or the damper reaches the fully open position.

When the supply-air temperature is between 55 F and 52 F, the supply-air thermostat has open switches between the T2 and 24 vac terminals and between the T1 and 24 vac terminals. This causes the economizer damper to remain in an intermediate open position.

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Contents Unit 581B036-072 FEATURES/BENEFITSEasy Maintenance and Installation Unit 581B090-150FEATURES/BENEFITS Table of Contents Model Number Nomenclature ServiceabilityCompressors and Safety Switches are Easily Accessible for Indoor AIR Quality IAQARI* Capacities Heating Capacities and EfficienciesTime Guard II Control Options and AccessoriesLOW Ambient Controls Liquid Propane Conversion KITOptions and Accessories Bryant Commercial Programmable Thermostat Hail Guard Accusensor II Enthalpy ControlCoil Guard Grille Bryant Light Commercial ThermidistatPhysical Data Hi-Static090N††† Physical Data060N††† 120N†††090 102 120 150 Nominal Capacity tons LOSS-OF-CHARGE LOW-PRESSURE Base Unit Dimensions 581B036-072Base Unit Dimensions 581B090-150Accessory Dimensions 581B036-072 Control Accessory Dimensions 581B090-150Connector ALT Drain PKG. Accy GAS CRRFCURB003A00II Select Unit Based on Required Cooling Capacity Selection Procedure With 581B048 ExampleDetermine NET Cooling Capacity Performance Data Cooling CapacitiesPerformance Data Cooling Capacities581B090 71/2 Tons 581B120 10 Tons Temp F Cooling CAPACITIES, Units with Perfect Humidity Option Cooling CAPACITIES, Units with Perfect Humidity Option 2250/0.10 3000/0.11 3750/0.14 Condenser 134.3 581B036 3 Tons Standard Motor Airflow FAN Performance Vertical Discharge Units581B036 3 Tons HIGH-STATIC Motor Airflow 581B048 4 Tons Standard Motor Airflow FAN Performance Vertical Discharge Units581B048 4 Tons HIGH-STATIC Motor Airflow 581B060 5 Tons Standard Motor THREE-PHASE Units Airflow 581B060 5 Tons Standard Motor SINGLE-PHASE Units Airflow581B060 5 Tons HIGH-STATIC Motor 581B072 6 Tons Standard Motor Airflow 581B072 6 Tons HIGH-STATIC Motor581B090 71/2 Tons Standard Motor 581B090 71/2 Tons HIGH-STATIC Motor Airflow581B102 81/2 Tons HIGH-STATIC Motor Airflow 581B120 10 Tons Standard and HIGH-STATIC Motor Airflow FAN Performance Horizontal Discharge Units FAN Performance Horizontal Discharge Units 581B060 5 Tons Standard Motor 3-PHASE Units Airflow 581B060 5 Tons HIGH-STATIC Motor Airflow2000 1022 1121 1188 1264 Bhp Rpm 1800 885 942 10471900 982 1084 1160 1223 2100 1063 1140 1196 1272581B090 71/2 Tons HIGH-STATIC Motor Airflow 2700 573 648 711 770 798 827 Bhp Rpm 2550 627 692 754 783 8122600 557 634 698 759 787 816 2800 588 662 723 782 809 8373300 537 692 751 828 3100 500 669 731 8083200 519 680 741 818 3400 561 704 761EVAPORATOR-FAN Motor Efficiency Outdoor Sound Power Total UnitFiop Perfect Humidity Dehumidification 581B FAN RPM AT Motor Pulley Setting with HIGH-STATIC Motor 581B FAN RPM AT Motor Pulley Setting with Standard MotorEVAPORATOR-FAN Motor Data Standard Motor EVAPORATOR-FAN Motor Data HIGH-STATIC Motors Operating WattsEconoMi$er Outdoor-Air Leakage EconoMi$er Barometric Relief Damper CharacteristicsEconoMi$er Return-Air Pressure Drop Altitude Derating Factor Altitude Compensation581B036-150 Supply Electrical DataOFM FAN MotorElectrical Data RLA LRA FLA MCA MOCP†Nominal Voltage Combustion Power Minimum Unit Compressor RLA LRA Application Data Maximum Operating OUTDOOR-AIR TemperatureApplications Application Data Perfect Humidity Dehumidification Option Pressure Enthalpy Curve Psychrometric Chart 581B072 Shown Vertical Discharge Typical Piping and WiringHorizontal Discharge Typical Wiring Schematic Typical Wiring Schematic OFC 581B090-150 Typical Wiring SchematicTran Operating Sequence for 581B036-072 Units ControlsOperating Sequence for 581B090-150 Units Controls Operating Sequence for 581B036-150 Size UnitsPart 1 General Guide SpecificationsPart 2 Products Guide Specifications Light Commercial Thermidistat Page Specifications Subject to Change Without Notice
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581B specifications

The Bryant 581B is an innovative and highly efficient gas furnace that stands out in the HVAC market for its remarkable performance, reliability, and advanced features. Designed to provide optimal heating comfort, the Bryant 581B is perfect for homeowners seeking both quality and energy efficiency.

One of the main features of the Bryant 581B is its impressive Annual Fuel Utilization Efficiency (AFUE) rating. With an AFUE rating of up to 80%, this gas furnace maximizes energy usage, ensuring that a significant portion of the fuel is converted into heat for your home. This efficiency not only translates into lower energy bills but also reduces the carbon footprint, making it an environmentally friendly choice.

The furnace is equipped with a multi-speed blower motor that enhances comfort by providing consistent airflow throughout the home. This technology adjusts to different heating demands, ensuring that every room reaches the desired temperature without the discomfort of hot or cold spots. The quiet operation of the blower motor also adds to the overall comfort, creating a peaceful home environment.

Another notable characteristic of the Bryant 581B is its durable construction. It features a robust heat exchanger built from high-quality materials, designed to withstand the rigors of daily use. The compact design of the furnace allows it to fit seamlessly into various spaces, making it an ideal choice for both new installations and replacement projects.

The Bryant 581B also comes with advanced safety features, including a self-diagnostic control board that monitors the system's performance. This feature allows for easy troubleshooting and maintenance, prolonging the life of the furnace. Additionally, the furnace is equipped with an induced draft blower that enhances venting efficiency and safety by ensuring that combustion gases are safely expelled from the home.

For homeowners looking for enhanced control, the Bryant 581B is compatible with a range of smart thermostats, providing the ability to monitor and adjust heating settings remotely. This integration with smart technology ensures that homeowners can maintain their desired comfort levels while maximizing efficiency.

In conclusion, the Bryant 581B gas furnace is a top-tier option that combines efficiency, durability, and modern technology. With its high AFUE rating, multi-speed blower, and advanced safety features, it promises to deliver unparalleled comfort and peace of mind for years to come. Whether for a new build or an upgrade, the Bryant 581B is an investment that pays off in both comfort and savings.
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