Table 36—Perfect HumidityAdaptive Dehumidification System Subcooling Mode Service Analysis

PROBLEM

CAUSE

 

REMEDY

Subcooling Mode (Liquid Reheat)

No power to control transformer from

Check power source and evaporator-fan relay. Ensure all

Will Not Energize.

evaporator-fan motor.

wire connections are tight.

 

No power from control transformer to liquid line

1.

Fuse open; check fuse. Ensure continuity of wiring.

 

solenoid valve.

2.

Low-pressure switch open. Cycle unit off and allow

 

 

 

low-pressure switch to reset. Replace switch if it will

 

 

 

not close.

 

 

3. Transformer bad; check transformer.

 

Liquid line solenoid valve will not operate.

1.

Solenoid coil defective; replace.

 

 

2.

Solenoid valve stuck open; replace.

 

Liquid line solenoid valve will not open.

Valve is stuck closed; replace valve.

Low System Capacity.

Low refrigerant charge or frosted evaporator coil.

1.

Check charge amount. Charge per Fig. 53---56.

 

 

2.

Evaporator coil frosted; check and replace low-pres-

 

 

 

sure switch if necessary.

Loss of Compressor Superheat

Thermostatic expansion valve (TXV).

1.

Check TXV bulb mounting, and secure tightly to suc-

Conditions with Subcooling/Reheat

 

2.

tion line.

Dehumidification Coil Energized.

 

Replace TXV if stuck open or closed.

Table 37—Perfect HumidityAdaptive Dehumidification System Hot Gas Reheat Mode Service Analysis

PROBLEM

CAUSE

 

REMEDY

Reheat Mode Will Not Energize.

No power to control transformer from

Check power source and evaporator-fan relay. Ensure all

 

evaporator-fan motor.

wire connections are tight.

 

No power from control transformer to hot gas

1.

Fuse open; check fuse. Ensure continuity of wiring.

 

line solenoid valve

2.

Low-pressure switch open. Cycle unit off and allow

 

 

 

low-pressure switch to reset. Replace switch if it will

 

 

 

not close.

 

 

3. Transformer bad; check transformer.

 

Hot gas line solenoid valve will not operate.

1.

Solenoid coil defective; replace.

 

 

2.

Solenoid valve stuck closed; replace.

 

Low refrigerant charge or frosted evaporator coil.

1.

Check charge amount. Charge per Fig. 53---56.

 

 

2.

Evaporator coil frosted; check and replace low-pres-

 

 

 

sure switch if necessary.

Loss of Compressor Superheat

Thermostatic expansion valve (TXV).

1.

Check TXV bulb mounting, and secure tightly to suc-

Conditions with Subcooling/Reheat

 

2.

tion line.

Dehumidification Coil Energized.

 

Replace TXV if stuck open or closed.

Excessive Superheat.

Liquid line solenoid valve will not operate.

Valve is stuck, replace valve.

 

Hot gas line solenoid valve will not close.

Valve is stuck; replace valve.

551B,C

Table 38—EconoMi$er IV Input/Output Logic

 

INPUTS

 

 

 

 

 

OUTPUTS

 

Demand Control

Enthalpy*

 

 

 

Compressor

N Terminal†

Outdoor

Return

Y1

Y2

Stage

Stage

Occupied

Unoccupied

Ventilation (DCV)

 

 

1

2

Damper

 

 

 

 

 

Below set

High

Low

On

On

On

On

Minimum position

Closed

(DCV LED Off)

(Free Cooling LED Off)

 

 

 

 

 

 

 

 

On

Off

On

Off

 

 

 

 

 

Off

Off

Off

Off

 

 

 

Low

High

On

On

On

Off

Modulating** (between min.

Modulating** (between

 

(Free Cooling LED On)

 

 

 

 

 

position and full-open)

closed and full-open)

 

 

On

Off

Off

Off

 

 

 

Off

Off

Off

Off

Minimum position

Closed

Above set

High

Low

On

On

On

On

Modulating†† (between min.

Modulating†† (between

(DCV LED On)

(Free Cooling LED Off)

 

 

 

 

 

position and DCV maximum)

closed and DCV

 

On

Off

On

Off

 

 

 

 

 

 

 

 

maximum)

 

 

 

Off

Off

Off

Off

 

 

 

 

 

 

 

Low

High

On

On

On

Off

Modulating***

Modulating†††

 

(Free Cooling LED On)

 

 

 

 

 

 

 

 

 

On

Off

Off

Off

 

 

 

 

 

Off

Off

Off

Off

 

 

*For single enthalpy control, the module compares outdoor enthalpy to the ABCD set point.

†Power at N terminal determines Occupied/Unoccupied setting: 24 vac (Occupied), no power (Unoccupied). **Modulation is based on the supply-air sensor signal.

††Modulation is based on the DCV signal.

***Modulation is based on the greater of DCV and supply-air sensor signals, between minimum position and either maximum position (DCV) or fully open (sup- ply-air signal).

†††Modulation is based on the greater of DCV and supply-air sensor signals, between closed and either maximum position (DCV) or fully open (supply-air sig- nal).

59

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Bryant 551C, 551B installation instructions EconoMi$er IV Input/Output Logic, Inputs Outputs

551C, 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.