Bard W18AA-A Installation Instructions Manual

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Bard W18AA-A Installation Instructions Manual Manual pdf 21 page image

Manual 2100-640FPage 21 of 32first check to make sure that either the optional vent isplugged into the vent connection plug or the suppliedjumper plug is in place. The unit will not operatewithout anything plugged in. This plug is located onthe side of the control panel behind the front vent door(behind the filter access door). If the unit is suppliedwith a factory-installed vent package, it will be pluggedin but the jumper plug will also be tethered next to theconnection for troubleshooting purposes, if necessary.COMPRESSOR CONTROL MODULEThe compressor control module is standard on allmodels covered by this manual. The compressorcontrol module is an anti-short cycle/lockout timer withhigh and low pressure switch monitoring and alarmrelay output.Adjustable Delay-on-Make and Delay-on-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 are closed, thecompressor contactor is energized. Upon shutdown,the delay-on-break timer starts and prevents restartuntil the delay-on-break and delay-on-make periodshave 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 lockouttimer will go into a soft lockout and stay in soft lockoutuntil the high pressure switch closes and the delay-on-break time has expired. If the high pressure switchopens again in this same operating cycle, the unit willgo into manual lockout condition and the alarm relaycircuit will energize. Recycling the wall thermostatresets the manual lockout.Low Pressure Switch, Bypass and Lockout SequenceIf the low pressure switch opens for more than 120seconds, the compressor contactor will de-energize andgo into a soft lockout. Regardless the state of the lowpressure switch, the contactor will re-energize 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 highpressure switch and low pressure switch cutout and cut in settings are fixed by specific airconditioner unit model. The lockout features,both soft and manual, are a function of thecompressor 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 and low pressure service ports are installed onall units so that the system operating pressures canbe observed. A pressure table covering all models canbe found on page 25. It is imperative to match thecorrect pressure table to the unit by model number.This unit employs high-flow Coremax valves instead ofthe typical Shrader type valves.WARNING! Do NOT use a Schrader valve core removaltool with these valves. Use of such a tool could resultin eye injuries or refrigerant burns!To change a Coremax valve without first removing therefrigerant, a special tool is required which can beobtained at www.fastestinc.com/en/SCCA07H. See thereplacement parts manual for replacement core partnumbers.