Start UP

IMPORTANT INSTALLER NOTE

For improved start up performance, wash the indoor coil with a dishwasher detergent.

SERVICE HINTS

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

2.The unit is equipped with a high pressure cut out switch.

3.Check all power fuses or circuit breakers to be sue they are the correct rating.

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

HIGH PRESSURE SWITCH

The WA121 models are supplied with a remote reset high pressure switch. If tripped, this pressure switch may be reset by turning the thermostat off then back on again.

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 a call for heating, circuit R-W1 make at the thermostat pulling in heat contact for the strip heat and blower operation.

COMPRESSOR CONTROL MODULE

The compressor control module is optional 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 on break time 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 that 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.

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WA121 specifications

The Bard WA121 is a cutting-edge heating and cooling unit that has been designed for residential and light commercial applications. With a focus on energy efficiency and user comfort, the WA121 stands out in the competitive HVAC market. One of its most notable features is its energy efficiency rating, which meets or exceeds the standards set by the Department of Energy. This translates to significant savings on utility bills, ultimately benefiting both the environment and the consumer's wallet.

A key characteristic of the Bard WA121 is its advanced direct expansion system. This feature allows for optimal heat transfer, resulting in quick and effective temperature regulation. The unit is equipped with a high-efficiency scroll compressor that ensures smooth operation and reduced noise levels, making it suitable for installation in residential settings without disrupting daily life.

The versatile design of the WA121 enables it to be used in various applications, from offices and schools to workshops. Its compact structure means that it can be easily integrated into tight spaces while still delivering robust performance. The unit is built to withstand harsh conditions, featuring a durable cabinet that is made from galvanized steel and finished with a weather-resistant powder coating.

Another outstanding feature is the integrated microprocessor control. This technology allows for precise temperature management, ensuring consistent comfort levels throughout the space. Additionally, the WA121 comes with a programmable thermostat option, providing users with the flexibility to optimize energy consumption based on usage patterns.

The Bard WA121 also focuses on user convenience with its easy-to-access maintenance points. The design allows technicians to perform routine service checks and repairs without excessive disassembly, thereby reducing downtime and maintenance costs.

In terms of airflow, the WA121 utilizes a multi-speed fan that can adjust to varying conditions, ensuring that air distribution remains efficient regardless of external temperatures. This adaptability enhances the overall performance of the unit, making it an ideal choice for diverse environments.

Overall, the Bard WA121 is engineered with a blend of efficiency, durability, and user-friendliness that positions it as a reliable solution for heating and cooling needs. With its commitment to performance and innovation, it is a solid investment for those looking to upgrade their HVAC systems.