Bard WA611, WA702-A, WA721, WA701-C Service Hints, Sequence of Operation, Compressor Control Module

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SERVICE HINTS

1.Caution homeowner to maintain clean air filters at all times. Also, not to needlessly close off supply and return air registers. This reduces air flow through the system, which shortens equipment service life as well as increasing operating costs.

2.Check all power fuses or circuit breakers to be sure they are the correct rating.

3.Periodic cleaning of the outdoor coil to permit full and unrestricted airflow circulation is essential.

SEQUENCE OF OPERATION

COOLING – Circuit R-Y makes at thermostat pulling in compressor contactor, starting the compressor and outdoor motor. The G (indoor motor) circuit is automatically completed on any call for cooling operation or can be energized by manual fan switch on subbase for constant air circulation. On all 208/230 volt models, when G circuit is de-energized the indoor blower motor will continue to run for one minute. On a call for heating, circuit R-W1 make at the thermostat pulling in heat contact for the strip heat and blower operation. On a call for second stage heat, R-W2 makes bringing on second heat contactor, if so equipped.

COMPRESSOR CONTROL MODULE

The compressor control module is standard on the models covered by this manual. The compressor control is an anti-short cycle/lockout timer with high and low pressure switch monitoring and alarm relay output.

Adjustable Delay On Make And Break Timer

On initial power up or any time power is interrupted to the unit the delay on make period begins which will be 2 minutes plus 10% of the delay on break setting. When the delay on make is complete and the high pressure switch (and low pressure switch if employed) is closed, the compressor contactor is energized. Upon shutdown the delay or break timer starts and prevents restart until the delay on break and delay on make periods have expired.

During routine operation of the unit with no power interruptions the compressor will operate on demand with no delay.

High Pressure Switch and Lockout Sequence

If the high pressure switch opens, the compressor contactor will de-energize immediately. The lockout timer will go into a soft lockout and stay in soft lockout until the high pressure switch closes and the delay on break time has expired. If the high pressure switch opens again in this same operating cycle the unit will go into manual lockout condition and the alarm relay circuit will energize. Recycling the wall thermostat resets the manual lockout.

Low Pressure Switch, Bypass, and Lockout Sequence

If the low pressure switch opens for more than 120 seconds, the compressor contactor will de-energize and go into a soft lockout. Regardless the state of the low pressure switch, the contactor will reenergize after the delay on make time delay has expired. If the low pressure switch remains open, or opens again for longer than 120 seconds the unit will go into manual lockout condition and the alarm relay circuit will energize. Recycling the wall thermostat resets the manual lockout.

Alarm Relay Output

Alarm terminal is output connection for applications where alarm relay is employed. This terminal is powered whenever compressor is locked out due to HPC or LPC sequences as described.

NOTE: Both high and low pressure switch controls are inherently automatic reset devices. The high pressure switch and low pressure switch cut out and cut in settings are fixed by specific air conditioner or heat pump unit model. The lockout features, both soft and manual, are a function of the Compressor Control Module.

Manual 2100-425 Page 15

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Contents INSTRUCTIONSWA701-BWA701-C WA702-A WA721 Wall Mounted Packaged AIR ConditionerContents For More INFORMATION, Contact These Publishers Getting Other Information and PublicationsElectric Heat Table Wall Mount General InformationAIR Conditioner Wall Mount Model Nomenclature Unit Dimensions Electrical Specifications Duct Work Shipping DamageGeneral Filters Blower Damper AssemblyFresh AIR Intake Condensate DrainTypical Installations Installation InstructionsWiring Main Power Wall Mounting InformationMounting Instructions Thermostat Wire Size Wiring LOW Voltage WiringOperating Voltage Range Wall Thermostat and Subbase CombinationsWALL-MOUNTING Instructions Common WALL-MOUNTING Installations Electric Heat Clearance LOW Voltage Wiring High Pressure Switch Important Installer NoteThree Phase Scroll Compressor Start UP Information Start UPCompressor Control Module Service HintsSequence of Operation Phase Monitor AdjustmentsPressure Service Ports Adjustable Delay on Make and Delay on Break TimerFAN Blade Setting Dimensions TroubleshootingRemoval of FAN Shroud Refrigerant ChargeMaximum ESP of Operation Electric Heat only Cooling Pressure All temperatures FOptional Accessories Page Page Page

WA701-C, WA701-B, WA611, WA721, WA702-A specifications

The Bard WA702-A, WA721, WA611, WA701-B, and WA701-C are part of Bard's renowned series of wall-mounted HVAC units designed for superior heating and cooling performance in various applications, particularly in the commercial and residential sectors. Each model boasts distinctive features and technologies that cater to specific comfort needs and energy efficiency requirements.

The Bard WA702-A model is noted for its energy-efficient engineering. It utilizes advanced scroll compressor technology, ensuring quiet operation and improved reliability. The unit’s high seasonal energy efficiency ratio (SEER) allows it to operate effectively in a variety of climate conditions, providing economic savings on energy bills.

The WA721 model takes efficiency a step further by incorporating Bard’s innovative electric heat option, which delivers rapid heating capabilities. This model is suitable for colder climates where quick temperature adjustments are essential. Its compact design allows for easy installation without compromising space, making it ideal for both residential and light commercial settings.

The WA611 is engineered with versatility in mind. This model supports multi-zone heating and cooling, allowing users to adjust temperatures in different areas independently. Its advanced controls facilitate optimal comfort while minimizing energy consumption. The WA611 also features an integrated air filtration system to enhance indoor air quality, which is a significant consideration in modern HVAC systems.

For those seeking dual functionality, the WA701-B and WA701-C models stand out with their remarkable heating and cooling capabilities. Both units are equipped with Bard’s patented thermal expansion valve (TXV) that optimizes refrigerant flow for improved efficiency across varying loads. The WA701 series includes robust insulation to reduce noise levels and enhance performance during operation.

In addition to their energy-efficient and space-saving designs, all models feature easy-to-use digital controls, enabling users to adjust settings conveniently. Moreover, the units are constructed with durable materials, providing long-lasting performance even in demanding environments.

Overall, the Bard WA series represents a blend of innovative technology, efficiency, and user-friendly designs that address the ever-changing needs of heating and cooling in contemporary spaces. Whether it’s for residential purposes or commercial applications, these models stand out for their promising performance and reliability, ensuring comfort and satisfaction for users.
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