7.Shall have an LED display independently showing the status of serial communication, running, errors, power, all digital outputs, and all analog inputs.

8.Shall accept the following inputs: space temperature, setpoint adjustment, outdoor air temperature, indoor air qu- ality, outdoor air quality, compressor lock-out, fire shutdown, enthalpy switch, and fan status/filter status/humid- ity/remote occupancy.

9.Shall provide the following outputs: economizer, fan, cooling stage 1, cooling stage 2, heat stage 1, heat stage 2, heat stage 3/ exhaust/ reversing valve.

10.Shall have built-in surge protection circuitry through solid state polyswitches. Polyswitches shall be used on in- coming power and network connections. Polyswitches will return to normal when the “trip” condition clears.

11.Shall have a battery back-up capable of a minimum of 10,000 hours of data and time clock retention during power outages.

12.Shall have built-in support for Bryant technician tool.

13.Shall include an EIA-485 protocol communication port, an access port for connection of either a computer or a Bryant technician tool, an EIA-485 port for network communication to intelligent space sensors and displays, and a port to connect an optional LonWorks communications card.

14.Software upgrades will be accomplished by either local or remote download. No software upgrades through chip replacements are allowed.

23 09 33 Electric and Electronic Control System for HVAC

23 09 33.13 Decentralized, Rooftop Units:

23 09 33.13.A. General:

1.Shall be complete with self-contained low-voltage control circuit protected by a resettable circuit breaker on the 24-v transformer side. Transformer shall have 75VA capability.

2.Shall utilize color-coded wiring.

3.Shall include a central control terminal board to conveniently and safely provide connection points for vital con- trol functions such as: smoke detectors, phase monitor, economizer, thermostat, DDC control options, loss of charge, freeze switch, high pressure switches.

4.Unit shall include a minimum of one 8-pin screw terminal connection board for connection of control wiring.

5.Shall include integrated defrost system to prevent excessive frost accumulation during heating duty, and shall be controlled as follows:

a.Defrost shall be initiated on the basis of time and coil temperature.

b.A 30,60,90,120 minute timer shall activate the defrost cycle only if the coil temperature is low enough to indic- ate a heavy frost condition.

c.Defrost cycle shall terminate when defrost thermostat are satisfied and shall have a positive termination time of 10 minutes.

6.Defrost system shall also include:

a.Defrost Cycle Indicator LED.

b.Dip switch selectable defrost time between 30,60,90 and 120 minutes. Factory set at 30 minutes.

c.Molded plug connection to insure proper connection.

23 09 33.23.B. Safeties:

1.Compressor over-temperature, over current.

2.Loss of charge switch.

a.Units with 2 compressors shall have different sized connectors for the circuit 1 and circuit 2 low and high pres- sure switches. They shall physically prevent the cross-wiring of the safety switches between circuits 1 and 2.

b.Loss of charge switch shall use different color wire than the high pressure switch. The purpose is to assist the installer and service technician to correctly wire and or troubleshoot the rooftop unit.

3.High-pressure switch.

a.Units with 2 compressors shall have different sized connectors for the circuit 1 and circuit 2 low and high pres- sure switches. They shall physically prevent the cross-wiring of the safety switches between circuits 1 and 2.

b.High pressure switch shall use different color wire than the low pressure switch. The purpose is to assist the installer and service technician to correctly wire and or troubleshoot the rooftop unit.

4.Freeze protection thermostat, evaporator coil.

5.Automatic reset, motor thermal overload protector.

23 09 93 Sequence of Operations for HVAC Controls

23 09 93.13 Decentralized, Rooftop Units:

23 09 93.13 INSERT SEQUENCE OF OPERATION

548J

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Bryant 548J 23 09 33 Electric and Electronic Control System for Hvac, 23 09 93 Sequence of Operations for Hvac Controls
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548J specifications

The Bryant 548J is a high-efficiency gas furnace that combines advanced features and technologies to provide exceptional heating performance. Designed for residential applications, the furnace is notable for its ability to deliver consistent warmth while ensuring energy efficiency and reliability.

One of the main features of the Bryant 548J is its ultra-high efficiency rating, which allows homeowners to save significantly on energy costs. With an Annual Fuel Utilization Efficiency (AFUE) rating of up to 96.5%, this furnace is designed to convert a large portion of fuel into usable heat. This is a remarkable characteristic that not only reduces utility bills but also contributes to a lower environmental footprint.

The 548J is equipped with a modulating gas valve and a variable-speed blower motor. The modulating gas valve enables the furnace to adjust its heating output based on real-time temperature demands, ensuring a more precise heating experience. This results in reduced temperature fluctuations within the home, providing a comfortable living environment. The variable-speed blower motor works in tandem with the modulating valve, facilitating improved air circulation and efficient temperature control.

Additionally, the Bryant 548J features a durable and compact design, making it suitable for various installation spaces. Its quality construction ensures longevity, while the optional stainless steel heat exchanger enhances its reliability. The furnace also includes a quiet operation mode, which minimizes noise levels, ensuring that the unit works quietly in the background without disturbing the household's peace.

Integration with smart home technology is another advantage of the Bryant 548J. Homeowners have the option to connect the furnace to a Wi-Fi-enabled thermostat, allowing for remote temperature control and monitoring. This feature offers enhanced convenience and the ability to optimize energy use according to a homeowner’s schedule.

For peace of mind, the Bryant 548J comes with a range of warranties, protecting the consumer's investment. Bryant’s commitment to quality is reflected in their extensive primary heating testing procedures, which ensure that each unit meets strict performance criteria before it reaches the customer.

In summary, the Bryant 548J is an efficient and reliable gas furnace that embodies advanced heating technology. With features such as high AFUE ratings, modulating gas valves, variable-speed blowers, and smart home compatibility, it stands out as a formidable option for modern residential heating solutions.
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