Bard QA241D Installation Instructions Manual

Bard QA241D Installation Instructions Manual Manual pdf 23 page image

Manual 2100-438Page 21All three phase scroll compressors used in the QTECseries are wired identically internally. As a result, oncethe correct phasing is determined for a specific systemor installation, connecting properly phased power leadsto the same Fusite terminal should maintain properrotation direction. The direction of rotation of themotor may be changed by reversing any two lineconnections to the unit.COMPRESSOR CONTROL MODULEThe compressor control module is standard on allmodels covered by this manual. The compressorcontrol is an anti-short cycle/lockout timer with highand low pressure switch monitoring and alarm relayoutput.Adjustable Delay On Make And Break TimerOn initial power up or any time power is interrupted tothe unit the delay on make period begins which will be2 minutes plus 10% of the delay on break setting.When the delay on make is complete and the highpressure switch (and low pressure switch if employed)is closed, the compressor contactor is energized. Uponshutdown the delay on break timer starts and preventsrestart until the delay on break and delay on makeperiods 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 lockouttimer will go into a soft lockout and stay in soft lockoutuntil the high pressure switch closes and the delay onbreak 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 LockoutSequenceIf 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 reenergize after thedelay 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 manuallockout.Alarm Relay OutputAlarm terminal is output connection for applicationswhere alarm relay is employed. This terminal ispowered whenever compressor is locked out due to HPCor LPC sequences as described.NOTE: Both high and low pressure switch controls areinherently automatic reset devices. The highpressure switch and low pressure switch cut outand cut in settings are fixed by specific airconditioner or heat pump unit model. Thelockout features, both soft and manual, are afunction of the Compressor Control Module.ADJUSTMENTSAdjustable Delay on Make and Delay on BreakTimerThe 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 isequal to 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 secondsSERVICE HINTS1. Caution user to maintain clean air filters at alltimes. Also, not to needlessly close off supply airregisters. This may reduce air flow through thesystem, which shortens equipment service life aswell as increasing operating costs and noiselevels.2. Check all power fuses or circuit breakers to besure they are the correct rating.3. Periodic cleaning of the outdoor coil to permitfull and unrestricted airflow circulation isessential.