Selection Procedure with 548F048 Example

SELECTION PROCEDURE (WITH 548F048 EXAMPLE)

I DETERMINE COOLING AND HEATING LOADS AT DESIGN CONDITIONS.

Given:

Required Cooling Capacity (TC) . . . . . . . . . . 38,000 Btuh Sensible Heat Capacity (SHC). . . . . . . . . . . . 24,000 Btuh Required Heating Capacity . . . . . . . . . . . . . . 35,000 Btuh Outdoor Entering-Air Temperature db . . . . . . . . . . . . 95 F Outdoor-Air Winter Design Temperature . . . . . . . . . . .0° F Indoor-Air Winter Design Temperature . . . . . . . . . . . 70 F Indoor-Air

Temperature . . . . . . . . . 80 F edb (entering air, dry bulb) 67 F ewb (entering air, wet bulb)

Indoor-Air Quantity. . . . . . . . . . . . . . . . . . . . . . . .1600 cfm External Static Pressure . . . . . . . . . . . . . . . . . 0.45 in. wg Electrical Characteristics (V-Ph-Hz). . . . . . . . . . . 230-3-60

Enter the Electric Heating Capacities table (page 54) for 548F048 at 208/230, 3 phase. The 6.5-kW heater at 240 v most closely satisfies the heating required. To calcu- late kW at 230 v, use the Multiplication Factors table.

6.5 kW x .92 = 5.98 kW

6.5 kW x .92 x 3413 = 20,410 Btuh

Total unit heating capacity is 38,410 Btuh (18,000 + 20,410).

IV DETERMINE FAN SPEED AND POWER REQUIRE- MENTS AT DESIGN CONDITIONS.

Before entering Fan Performance tables, calculate the total static pressure required based on unit components. From the given and the Pressure Drop tables, find:

External static pressure

.45 in. wg

548F036-120

IISELECT UNIT BASED ON REQUIRED COOLING CAPACITY.

Enter Cooling Capacities table at outdoor entering temper- ature of 95 F, indoor air entering at 1600 cfm and 67 F ewb. The 548F048 unit will provide a total cooling capacity of 49,900 Btuh and a sensible heat capacity of 33,900 Btuh.

For indoor-air temperature other than 80 F edb, calculate sensible heat capacity correction, as required, using the formula found in Note 3 following the cooling capacities tables.

NOTE: Unit ratings are gross capacities and do not include the effect of indoor-fan motor heat. To calculate net capacities, see Step V.

IIISELECT ELECTRIC HEAT.

Enter the Instantaneous and Integrated Heating Ratings table at 1600 cfm. At 70 F return indoor air and 0° F air entering outdoor coil, the integrated heating capacity is 18,000 Btuh. (Select integrated heating capacity value since deductions for outdoor-coil frost and defrosting have already been made. No correction is required.)

The required heating capacity is 35,000 Btuh. Therefore, 17,000 Btuh (35,000 – 18,000) additional electric heat is required.

Determine additional electric heat capacity in kW.

17,000 Btuh

= 5.0 kW of heat required.

3413 Btuh/kW

Durablade economizer	.05 in. wg
Electric heat	.09 in. wg
Total static pressure	.59 in. wg

Enter the Fan Performance table for 548F048 vertical dis- charge. At 1600 cfm and 230-v high speed, the standard motor will deliver 0.76 in. wg static pressure, 723 watts, and 0.64 brake horsepower (bhp). This will adequately handle job requirements.

VDETERMINE NET CAPACITIES.

Capacities are gross and do not include the effect of indoor-fan motor (IFM) heat.

Determine net cooling capacity as follows: Net capacity = Total capacity – IFM heat

=49,900 Btuh – (723 Watts x 3.413 Btuh/Watts)

=49,900 Btuh – 2468 Btuh

=47,432

Net sensible capacity = 33,900 Btuh – 2468 Btuh

= 31,432 Btuh

Integrated heating capacity is maximum (instantaneous) capacity less the effect of frost on the outdoor coil and the heat required to defrost it. Therefore, net capacity is equal to 38,410 Btuh, the total heating capacity determined in Step III.

549B, 548F, 542J specifications

Bryant 542J is a high-efficiency gas furnace that stands out for its reliability and advanced heating technologies. Designed to deliver consistent warmth and comfort in residential settings, it combines innovative engineering with energy-efficient features.

One of the key characteristics of the Bryant 542J is its two-stage heating capability. This means that the furnace can adjust its heat output according to the heating demands of your home. During milder weather, it operates at a lower stage, consuming less energy while still maintaining a comfortable environment. When the temperatures drop, the furnace shifts to its higher capacity, providing the necessary warmth efficiently. This not only enhances comfort but also contributes to lower energy bills.

In addition to its two-stage operation, the Bryant 542J also incorporates a variable-speed blower motor. This technology allows the furnace to adjust the airflow depending on the heating requirements, ensuring an even distribution of warm air throughout the home. The variable-speed blower also operates more quietly than conventional fixed-speed motors, creating a serene indoor environment.

Energy efficiency is a hallmark of the Bryant 542J, boasting an Annual Fuel Utilization Efficiency (AFUE) rating of up to 96.5%. This impressive rating means that a significant portion of the energy consumed is effectively converted into usable heat, resulting in substantial savings on heating costs over time. Furthermore, the furnace is equipped with a sealed combustion system that draws air from outside the home, minimizing energy waste and improving indoor air quality.

Diagnostic features are another highlight of the Bryant 542J, which come equipped with SmartEvap technology. This allows the unit to self-diagnose potential issues, providing homeowners with peace of mind and simplifying maintenance procedures.

Durability is also a key feature of the Bryant 542J. It is constructed with high-quality materials designed to withstand harsh winter conditions, ensuring a long lifespan and reliable performance. Its compact design also allows for flexible installation, making it suitable for various residential layouts.

In summary, the Bryant 542J is more than just a gas furnace; it is a sophisticated heating solution that combines efficiency, comfort, and reliability. With features such as two-stage heating, a variable-speed blower, high AFUE ratings, and advanced diagnostics, it is an excellent choice for homeowners seeking an efficient and effective heating system.

Bryant 542J, 549B manual Selection Procedure with 548F048 Example, III Select Electric Heat

Models: 549B 548F 542J