Bryant 551B VII. Adjust EVAPORATOR-FAN Speed, Minimum Required Airflow Exceptions, Uration

Page 21

VII. STEP 7 — ADJUST EVAPORATOR-FAN SPEED

Adjust evaporator-fan rpm to meet jobsite conditions.

For units with electric heat, required minimum cfm is 2250 for 551B090 and 102 and 3000 for 551B120 and 150. See Table 8 for exceptions.

Table 8 — Minimum Required Airflow Exceptions

UNIT

UNIT

HEATER

UNIT

REQUIRED

CONFIG-

MINIMUM

551B

VOLTAGE

kW

URATION

CFM

 

 

 

 

208/230

42.4

Horizontal

3200

120,150

208/230

50.0

Horizontal

3200

460

50.0

Horizontal

3200

 

 

or Vertical

 

 

 

 

090-150

575

17.0

Horizontal

2800

34.0

or Vertical

2350

 

 

2.Slide fan pulley along fan shaft.

3.Make angular alignment by loosening motor from mounting plate.

To adjust belt tension:

1.Loosen fan motor mounting nuts.

2.Size 090 — Slide motor mounting plate away from fan

scroll for proper belt tension (1/2-in. deflection with 8 to 10 lb of force) and tighten mounting nuts (see Fig. 37).

Sizes 102-150 — Slide motor mounting plate down- ward to tighten belt tension. Secure motor mounting

plate nuts. See Fig. 38. Use 1/2-in. deflection with 10 lb of force.

3.Adjust bolt and nut on mounting plate to secure motor in fixed position.

Tables 9 and 10 show fan rpm at motor pulley settings for standard and high-static motors. Tables 11 and 12 show evaporator-fan motor data. See Tables 13 and 14 and Fig. 36 for accessory and option static pressure drops. Refer to Tables 15-28 to determine fan speed settings.

Fan motor pulleys are factory set for speed shown in Table 1.

To change fan speeds:

1.Shut off unit power supply and install lockout tag.

2.Loosen belt by loosening fan motor mounting nuts. See Fig. 37 and 38.

3.Loosen movable pulley flange setscrew (see Fig. 39).

4.Screw movable flange toward fixed flange to increase rpm or away from fixed flange to decrease rpm. Increasing fan rpm increases load on motor. Do not exceed maximum speed specified in Table 1.

5.Set movable flange at nearest keyway of pulley hub and tighten setscrew. (See Table 1 for speed change for each full turn of pulley flange.)

To align fan and motor pulleys:

1. Loosen fan pulley setscrews.

MOTOR MOUNTING

PLATE NUTS

Fig. 37 — Typical Belt-Drive Motor Mounting for

Size 090

DELTA P IN. WG

0.35

0.3

0.25

0.2

0.15

0.1

0.05

0

7.5 ton

8.5, 10 & 12.5 ton

0

1000

2000

3000

4000

5000

6000

CFM

Fig. 36 — Perfect Humidity™ Dehumidification System Static Pressure Drop (in. wg)

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Contents Safety Considerations ContentsInstallation Provide Unit SupportIII. Install Condensate Drain Line and External Trap IV. RIG and Place UnitPositioning Roof Curb Details Operating WeightBase Unit Dimensions Unit 551B Physical DataMake Electrical Connections Field Power SupplyIFC NECFLA MCA Mocp LRA Hacr Electrical DataVoltage Comp no Electric Heater †Used to determine minimum disconnect per NEC Electric Heater UsageHeat Anticipator Settings Field Control WiringVI. Adjust FACTORY-INSTALLED Options A. Disconnect Switch Perfect Humidity Dehumidification SystemAccessory Field-Installed Humidistat Convenience Outlet Manual Outdoor-Air DamperOptional EconoMi$er Hood Box Removal EconoMi$er IV Standard SensorsOutdoor-Air Hood Construction EconoMi$er IV Sensor Usage EconoMi$er IV Control ModesEconoMi$er IV Controller Potentiometer LED Locations Enthalpy Changeover Set Points Page Ppm CO2 Sensor Standard SettingsUnit Heater Required Config VII. Adjust EVAPORATOR-FAN SpeedMinimum Required Airflow Exceptions UrationFan Rpm at Motor Pulley Setting* Standard Motor/Drive Fan Rpm at Motor Pulley Setting* High-Static Motor/DriveEvaporator-Fan Motor Data Standard Motor Accessory/FIOP Electric Heaters Static Pressure in. wg Accessory/FIOP EconoMi$er IV Static Pressure* in. wgEvaporator-Fan Motor Data High-Static Motors General FAN Performance NotesAirflow 866 697 1088 756 1324 832 690 1051 750 1285901 703 1125 762 1365 974 716 1204 774 1449506 629 625 688 745 489 386866 502 4241656 15671748 1844805 695 953 749 1100 799 1249 748 684 891 738 1034 789 1177865 707 760 1170 809 1323929 718 1086 771 1244 820 1401 865 707 1018 760 1170 809 13231665 1873668 1116 726 654 1040 713683 1197 739 697 1281 753596 629 802 694 1021 465 4021252 471 421882 684 1125 746 1378 823 674 1059 737 1306944 695 1194 756 1453 1009 705 1266 766 1533467 614 594 681 728 462 348868 474 3812821 27162293 996 2501 1038 2713 29301677 808 1876 855 2081 710 1482723 1577 1775 820 19781582 796 1777 1492 784 16831677 808 1876 1877781 1445 614 929 673628 997 685 791 1525VI. Refrigerant Service Ports Internal WiringPRE-START-UP START-UP Unit PreparationXI. Safety Relief Heating if Accessory Heater is InstalledIX. Cooling XII. Ventilation Continuous FANPerfect Humidity System Normal Design Cooling Operation Service Cleaning Units With Power ExhaustEvaporator Coil Condenser CoilsIV. BELT/PULLEY Adjustment III. CONDENSER-FAN Adjustment FIGECONOMI$ER IV Adjustment II. LubricationCooling Charging Charts, Standard 551B090 Unit Cooling Charging Charts, Standard 551B120 Unit VII. Replacement Parts Troubleshooting Unit Troubleshooting Cooling TroubleshootingProblem Cause Remedy Reheat Mode Will Not Energize Subcooling Mode Liquid ReheatWill Not Energize Low System CapacityII. ECONOMI$ER IV Troubleshooting EconoMi$er IV Input/Output Logic EconoMi$er IV Troubleshooting CompletionInputs Outputs Demand Control EnthalpyIndex Operating sequence Cooling EconoMi$er HeatingPage Temperatures START-UP ChecklistPreliminary Information 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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