When the second stage of cooling is satis®ed, the compressor and OFM will be deenergized. The damper position will be determined by the supply-air temperature.

When the ®rst stage of cooling is satis®ed, there is a 30-second delay before evaporator shuts off (036-060). The damper will move to fully closed position.

Cooling, Units with PARABLADE Economizer

When the outdoor-air is above the enthalpy control setting, and the room thermostat calls for cooling, the compressor contactor is energized to start the compressor and the condenser (outdoor) fan motor. The evaporator (indoor) fan motor is energized and the economizer damper moves to the minimum position. After the room thermostat is satis®ed the damper will spring return to the full closed position.

When the outdoor-air is below the enthalpy control setting and the thermostat calls for cooling, the economizer outdoor air damper is opened proportionally to maintain between 50 and 56 F at the mixed air sensor. If outside air alone cannot satisfy the cooling requirements, economizer cooling is integrated with mechanical cooling. When the room ther- mostat is satis®ed, the damper will spring return to the fully closed position.

Time Guard II Device

If the unit is equipped with accessory Time Guard II recycle timer, the unit will delay 5 minutes between compressor starts.

Low-Pressure Switch (LPS)

When the liquid line pressure drops below 7 psig, the LPS opens 24-v power to the compressor contactor and stops the compressor. When the pressure reaches 22 psig, the switch resets and the compressor is allowed to come back on.

High-Pressure Switch (HPS)

When the refrigerant high-side pressure reaches 428 psig, the HPS opens 24-v power to the compressor contactor and stops the compressor. When the pressure drops to 320 psig, the switch resets and the compressor is allowed to restart.

Freeze Protection Thermostat (FPT)

When the evaporator coil leaving refrigerant temperature drops below 30 F, the FPT opens 24-v power to the compressor con- tactor and stops the compressor. When the leaving refriger- ant temperature warms to 45 F, the switch resets and the compressor is allowed to restart.

IV. INDOOR AIRFLOW AND AIRFLOW ADJUSTMENTS

CAUTION: For cooling operation, the recommended air¯ow is 300 to 500 cfm per each 12,000 Btuh of rated cooling capacity. For heating operation, the air¯ow must produce a temperature rise that falls within the range stamped on the unit rating plate.

Adjust evaporator-fan speed to meet jobsite conditions and temperature rise in Table 1. Table 7 shows fan rpm at motor pulley settings. Table 8 shows evaporator-fan motor per- formance. Refer to Tables 9-16 to determine fan speed settings.

A. Belt Drive Motors

Fan motor pulleys are factory set for speed shown in Table 1. Check pulley alignment and belt tension prior to start-up.

NOTE: Before adjusting fan speed, make sure the new fan speed will provide an air temperature rise range as shown in Table 1.

To change fan speed:

1.Shut off unit power supply.

2.Loosen belt by loosening fan motor mounting nuts. See Fig. 33.

3.Loosen movable pulley ¯ange setscrew (see Fig. 34).

4.Screw movable ¯ange toward ®xed ¯ange to increase speed and away from ®xed ¯ange to decrease speed. Increas- ing fan speed increases load on motor. Do not exceed maxi- mum speed speci®ed in Table 1.

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

To align fan and motor pulleys:

1.Loosen fan pulley setscrews.

2.Slide fan pulley along fan shaft.

3.Make angular alignment by loosening motor from mounting.

To adjust belt tension:

1.Loosen fan motor nuts.

2.Slide motor mounting plate away from fan scroll for proper belt tension (1¤2-in. de¯ection with one ®nger) and tighten mounting nuts.

3.Adjust lock bolt and nut on mounting plate to secure motor in ®xed position.

CAPACITOR

MOTOR

(581B036, 048

MOUNTING

SINGLE-PHASE

PLATE NUTS

UNITS ONLY)

 

Fig. 33 Ð Belt Drive Motor Mounting

Fig. 34 Ð Evaporator-Fan Pulley Adjustment

Ð22Ð

Page 21 Page 23
Page 22
Image 22
Bryant 581B installation instructions IV. Indoor Airflow and Airflow Adjustments, Belt Drive Motors
Page 21 Page 23

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.
Top Page Image Contents