Bryant 551B Troubleshooting Unit Troubleshooting, Cooling Troubleshooting, Problem Cause Remedy

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TROUBLESHOOTING

I. UNIT TROUBLESHOOTING

Refer to Tables 30-32 for additional information.

Table 30 — Cooling Troubleshooting

PROBLEM

CAUSE

REMEDY

Compressor(s) and

Power failure.

Call power company.

Condenser Fan

Fuse blown or circuit breaker tripped.

Replace fuse or reset circuit breaker.

Will Not Start.

Defective thermostat, contactor, transformer,

Replace component.

 

 

control relay.

 

 

Insufficient line voltage.

Determine cause and correct.

 

Incorrect or faulty wiring.

Check wiring diagram and rewire correctly.

 

Thermostat setting too high.

Lower thermostat setting below room temperature.

 

High pressure switch tripped.

See problem “Excessive Head Pressure.”

 

Low pressure switch tripped.

Check system for leaks, repair, and recharge.

 

Freeze-up protection thermostat tripped.

See problem “Suction Pressure Too Low.”

Compressor(s) Will Not

Faulty wiring or loose connections in compressor

Check wiring and repair or replace.

Start but Condenser Fan

circuit.

 

Runs.

 

 

Compressor motor(s) burned out, seized, or internal

Determine cause. Replace compressor(s).

 

 

overload open.

 

 

Defective overload.

Determine cause and replace.

 

One leg of 3-phase power dead.

Replace fuse or reset circuit breaker. Determine cause.

Compressor(s) Cycles

Refrigerant overcharge or undercharge.

Recover refrigerant, evacuate system, and recharge

(Other Than Normally

 

to nameplate.

Satisfying Thermostat).

 

 

Defective compressor.

Replace and determine cause.

 

 

Insufficient line voltage.

Determine cause and correct.

 

Blocked condenser.

Determine cause and correct.

 

Defective overload.

Determine cause and replace.

 

Defective thermostat.

Replace thermostat.

 

Faulty condenser-fan motor(s) or capacitor.

Replace.

 

Restriction in refrigerant system.

Locate restriction and remove.

Compressor(s) Operates

Dirty air filter.

Replace filter.

Continuously.

 

 

Unit undersized for load.

Decrease load or increase unit size.

 

 

Thermostat set too low.

Reset thermostat.

 

Low refrigerant charge.

Locate leak, repair, and recharge.

 

Leaking valves in compressor.

Replace compressor.

 

Air in system.

Recover refrigerant, evacuate system, and recharge.

 

Condenser coil dirty or restricted.

Clean coil or remove restriction.

Scroll Compressor(s)

Compressor(s) rotating in the wrong direction.

Reverse the 3-phase power leads as described in

Makes Excessive Noise.

 

Start-Up section, page 38.

Excessive Head Pressure.

Dirty air filter.

Replace filter.

 

Dirty condenser coil.

Clean coil.

 

Refrigerant overcharged.

Remove excess refrigerant.

 

Air in system.

Recover refrigerant, evacuate system to 500 microns,

 

 

and recharge.

 

Condenser air restricted or air short-cycling.

Determine cause and correct.

Head Pressure Too Low.

Low refrigerant charge.

Check for leaks, repair, and recharge.

 

Compressor valves leaking.

Replace compressor(s).

 

Restriction in liquid tube.

Remove restriction.

Excessive Suction

High heat load.

Check for source and eliminate.

Pressure.

 

 

Compressor valves leaking.

Replace compressor(s).

 

 

Refrigerant overcharged.

Recover excess refrigerant.

Suction Pressure Too Low.

Dirty air filter.

Replace filter.

 

Low refrigerant charge.

Check for leaks, repair, and recharge.

 

Metering device or low side restricted.

Remove source of restriction.

 

Insufficient evaporator airflow.

Increase air quantity. Check filter and replace if

 

 

necessary.

 

Temperature too low in conditioned area.

Reset thermostat.

 

Field-installed filter drier restricted.

Replace.

 

Outdoor ambient temperature below 25 F.

Install low-ambient kit.

Compressor No. 2

Unit in economizer mode.

Proper operation; no remedy necessary.

Will Not Run.

 

 

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Contents Installation ContentsSafety Considerations Provide Unit SupportIV. RIG and Place Unit III. Install Condensate Drain Line and External TrapPositioning Roof Curb Details Weight OperatingBase Unit Dimensions Physical Data Unit 551BIFC Field Power SupplyMake Electrical Connections NECElectrical Data FLA MCA Mocp LRA HacrVoltage Comp no Electric Heater Electric Heater Usage †Used to determine minimum disconnect per NECVI. Adjust FACTORY-INSTALLED Options A. Disconnect Switch Field Control WiringHeat Anticipator Settings Perfect Humidity Dehumidification SystemAccessory Field-Installed Humidistat Manual Outdoor-Air Damper Convenience OutletOptional EconoMi$er EconoMi$er IV Standard Sensors Hood Box RemovalOutdoor-Air Hood Construction EconoMi$er IV Control Modes EconoMi$er IV Sensor UsageEconoMi$er IV Controller Potentiometer LED Locations Enthalpy Changeover Set Points Page CO2 Sensor Standard Settings PpmMinimum Required Airflow Exceptions VII. Adjust EVAPORATOR-FAN SpeedUnit Heater Required Config UrationFan Rpm at Motor Pulley Setting* High-Static Motor/Drive Fan Rpm at Motor Pulley Setting* Standard Motor/DriveEvaporator-Fan Motor Data Standard Motor Evaporator-Fan Motor Data High-Static Motors Accessory/FIOP EconoMi$er IV Static Pressure* in. wgAccessory/FIOP Electric Heaters Static Pressure in. wg General FAN Performance NotesAirflow 901 703 1125 762 1365 832 690 1051 750 1285866 697 1088 756 1324 974 716 1204 774 1449866 489 386506 629 625 688 745 502 4241748 15671656 1844865 707 748 684 891 738 1034 789 1177805 695 953 749 1100 799 1249 760 1170 809 13231665 865 707 1018 760 1170 809 1323929 718 1086 771 1244 820 1401 1873683 1197 739 654 1040 713668 1116 726 697 1281 7531252 465 402596 629 802 694 1021 471 421944 695 1194 756 1453 823 674 1059 737 1306882 684 1125 746 1378 1009 705 1266 766 1533868 462 348467 614 594 681 728 474 3812293 996 2501 1038 2713 27162821 2930723 1577 710 14821677 808 1876 855 2081 1775 820 19781677 808 1876 1492 784 16831582 796 1777 1877628 997 685 614 929 673781 1445 791 1525PRE-START-UP Internal WiringVI. Refrigerant Service Ports START-UP Unit PreparationIX. Cooling Heating if Accessory Heater is InstalledXI. Safety Relief XII. Ventilation Continuous FANPerfect Humidity System Normal Design Cooling Operation Evaporator Coil Units With Power ExhaustService Cleaning Condenser CoilsECONOMI$ER IV Adjustment III. CONDENSER-FAN Adjustment FIGIV. BELT/PULLEY Adjustment II. LubricationCooling Charging Charts, Standard 551B090 Unit Cooling Charging Charts, Standard 551B120 Unit VII. Replacement Parts Cooling Troubleshooting Troubleshooting Unit TroubleshootingProblem Cause Remedy Will Not Energize Subcooling Mode Liquid ReheatReheat Mode Will Not Energize Low System CapacityII. ECONOMI$ER IV Troubleshooting Inputs Outputs EconoMi$er IV Troubleshooting CompletionEconoMi$er IV Input/Output Logic Demand Control EnthalpyOperating sequence Cooling EconoMi$er Heating IndexPage Preliminary Information START-UP ChecklistTemperatures III. START-UP Electrical
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551B specifications

The Bryant 551B and 551C are two highly efficient air conditioning units designed to provide optimal comfort in residential settings. Known for their reliability and performance, these models are part of Bryant's esteemed line of heating and cooling solutions.

One of the standout features of the Bryant 551B is its two-stage cooling system, which allows for better humidity control and increased comfort. This ensures that homeowners can enjoy consistent temperatures while reducing energy consumption. The unit operates quietly, thanks to its noise-reducing technology, making it an ideal choice for bedrooms and living spaces.

On the other hand, the Bryant 551C builds upon this foundation with its variable-speed compressor. This technology allows the unit to adjust its cooling output according to the specific needs of the home. This results in seamless operation and even greater energy efficiency. Both models also incorporate Bryant's advanced control capabilities, which allow users to monitor and adjust settings remotely via smart devices, adding a layer of convenience and modernity to home climate control.

With an emphasis on durability, both the 551B and 551C feature a galvanized steel cabinet that protects against weather-related damage. The powder coat finish further enhances their resistance to rust and corrosion, ensuring a long lifespan and minimal maintenance.

Another significant characteristic of these units is their excellent Seasonal Energy Efficiency Ratio (SEER) ratings. The 551B boasts a SEER rating of up to 16, while the 551C takes it even further with ratings exceeding 20. This efficiency not only translates to lower energy bills for homeowners but also contributes to a reduced carbon footprint, making these units environmentally friendly options.

Both models are also designed to operate with eco-friendly refrigerants, aligning with modern energy standards and regulations aimed at reducing greenhouse gas emissions.

In summary, the Bryant 551B and 551C are exemplary choices for homeowners looking for reliable, efficient, and high-performing air conditioning solutions. With features such as two-stage and variable-speed compressors, advanced smart technology, and robust construction, these models stand out in the competitive HVAC market. They promise a comfortable indoor environment along with significant energy savings, making them a wise investment for the future.
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