Bard H42A2-A Installation Instructions Manual

Also see for H42A2-A: Manual

Contents

Bard H42A2-A Installation Instructions Manual Manual pdf 14 page image

Manual 2100-585BPage 14 of 19START UP (Continued)CONDENSER FAN OPERATIONApplies to H42, H48 and H60 models only. NOTE:Certain models may be equipped with a Low AmbientControl (LAC), and if so equipped the condenser fanmotor will have delay start until system refrigerantoperationg pressure builds up. After starting, the fanmotor may or may not cycle depending upon ambientconditions. This is normal operation. The condenser fanmotor on 230/208 volt, one and three phase, 60 HZ units isa two-speed motor that comes factory wired on high speedfor peak performance. If ambient conditions permit, it canbe reconnected to low speed (red wire) for lower soundlevel. See wiring diagram.SERVICE HINTS1. Caution owner/operator to maintain clean airfilters at all times. Also, not to needlessly close offsupply and return air registers. This reduces airflowthrough the system, which shortens equipmentservice life as well as increasing operating costs.2. Check all power fuses or circuit breakers to be surethey are the correct rating.3. Periodic cleaning of the outdoor coil to permit fulland unrestricted airflow circulation is essential.SEQUENCE OF OPERATIONCOOLING – Circuit R-Y makes at thermostat pullingin compressor contactor, starting the compressorand outdoor motor. (See Note under Condenser FanOperation if equipped with Low Ambient Control.)The G (indoor motor) circuit is automaticallycompleted on any call for cooling operation or can beenergized by manual fan switch on subbase for constantair circulation. On a call for heating, circuit R-W1make at the thermostat pulling in heat contact for thestrip heat and blower operation. On a call for secondstage heat, R-W2 makes bringing on second heatcontactor, if so equipped.COMPRESSOR CONTROL MODULEThe compressor control module is standard on all modelscovered by this manual. The compressor control moduleis an anti-short cycle/lockout timer with high and lowpressure switch monitoring and alarm relay output.Adjustable Delay On Make And Break TimerOn initial power up or anytime power is interrupted tothe unit, the delay on make period begins, which willbe 2 minutes plus 10% of the delay on break setting.When the delay on make is complete and the highpressure switch and low pressure switch is closed, thecompressor contactor is energized. Upon shutdown, thedelay on break timer starts and prevents restart until thedelay on break and delay on make periods have expired.During routine operation of the unit with no powerinterruptions, the compressor will operate on demandwith no delay.High Pressure Switch and Lockout SequenceIf the high pressure switch opens, the compressorcontactor will de-energize immediately. The lockout timerwill go into a soft lockout and stay in soft lockout untilthe high pressure switch closes and the delay on breaktime has expired. If the high pressure switch opens againin this same operating cycle, the unit will go into manuallockout condition and the alarm relay circuit will energize.Recycling the wall thermostat resets the manual lockout.Low Pressure Switch, Bypass & Lockout SequenceIf the low pressure switch opens for more than 120seconds, the compressor contactor will de-energizeand go into a soft lockout. Regardless the state of thelow pressure switch, the contactor will reenergize afterthe delay on make time delay has expired. If the lowpressure switch remains open, or opens again for longerthan 120 seconds, the unit will go into manual lockoutcondition and the alarm relay circuit will energize.Recycling the wall thermostat resets the manual lockout.Alarm Relay OutputAlarm terminal is output connection for applicationswhere alarm relay is employed. This terminal ispowered whenever the compressor is locked out due toHPC or LPC sequences as described.NOTE:Both high and low pressure switch controls areinherently automatic reset devices. The high pressureswitch and low pressure switch cut out and cut insettings are fixed by specific air conditioner unitmodel. The lockout features, both soft and manual,are a function of the Compressor Control Module.ADJUSTMENTSAdjustable Delay on Make and Delay on Break TimerThe potentiometer is used to select Delay on Break timefrom 30 seconds to 5 minutes. Delay on Make (DOM)timing on power-up and after power interruptions is equalto 2 minutes plus 10% of Delay on Break (DOB) setting:0.5 minute (30 seconds) DOB = 123 second DOM1.0 minute (60 seconds) DOB = 126 second DOM2.0 minute (120 seconds) DOB = 132 second DOM3.0 minute (180 seconds) DOB = 138 second DOM4.0 minute (240 seconds) DOB = 144 second DOM5.0 minute (300 seconds) DOB = 150 second DOMDuring routine operation of the unit with no powerinterruptions the compressor will operate on demandwith no delay.Typical Settings for Dual Unit Installation:Unit 1: DOB set at 2 minutes, and DOM is 132 secondsUnit 2: DOB set at 4 minutes, and DOM is 144 secondsPRESSURE SERVICE PORTSHigh & low pressure service ports are installed on all unitsso that the system operating pressures can be observed. Apressure table can be found later in the manual covering allmodels. It is imperative to match the correct pressure tableto the unit by model number. See Table 2.