Bard WH611 Installation Instructions Manual

Also see for WH611: Installation instructions

Manual 2100-347HPage 18 of 23PHASE MONITORAll units with three phase compressors are equippedwith a 3 phase line monitor to prevent compressordamage due to phase reversal.The phase monitor in this unit is equipped with twoLEDs. If the Y signal is present at the phase monitorand phases are correct, the green LED will light. Ifphases are reversed, the red fault LED will be lit andcompressor operation is inhibited.If a fault condition occurs, reverse two of the supplyleads to the unit. Do not reverse any of the unit factorywires as damage may occur.SERVICE HINTS1. Caution owner/operator to maintain clean air filtersat all times. Also, not to needlessly close off supplyand return air registers. This reduces airflow throughthe system, which shortens equipment service life aswell as increasing operating costs.2. Switching to heating cycle at 75°F or higher outsidetemperature may cause a nuisance trip of the remotereset high pressure switch. Turn thermostat off thenon to reset the high pressure switch.3. The heat pump wall thermostats perform multiplefunctions. Be sure that all function switches arecorrectly set for the desired operating mode beforetrying to diagnose any reported service problems.4. Check all power fuses or circuit breakers to be surethey are the correct rating.5. 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 compressor andoutdoor motor. The G (indoor motor) circuit isautomatically completed on any call for coolingoperation or can be energized by manual fan switch onsubbase of constant air circulation.HEATING – A 24V solenoid coil on reversing valvecontrols heating cycle operation. Two thermostatoptions, one allowing “Auto” changeover from cycle tocycle and the other constantly energizing solenoid coilduring heating season and thus eliminating pressureequalization noise except during defrost, are to be used.On “Auto” option a circuit is completed from R-W1 andR-Y on each heating “on” cycle, energizing reversingvalve solenoid and pulling in compressor contactorstarting compressor and outdoor motor. R-G also makestarting indoor blower motor. Heat pump heating cyclenow in operation. The second option has no “Auto”changeover position, but instead energizes the reversingvalve solenoid constantly whenever the system switchon subbase is placed in “Heat” position, the “B”terminal being constantly energized from R. Athermostat demand for heat completes R-Y circuit,pulling in compressor contactor starting compressor andoutdoor motor. R-G also make starting indoor blowermotor.PRESSURE SERVICE PORTSHigh and Low pressure service ports are installed on allunits so that the system operating pressures can beobserved. Pressure tables can be found later in themanual covering all models on both cooling and heatingcycles. It is imperative to match the correct pressuretable to the unit by model number.DEFROST CYCLEThe defrost cycle is controlled by temperature and timeon the solid state heat pump control. See Figure 15.When the outdoor temperature is in the lower 40°Ftemperature range or colder, the outdoor coiltemperature is 32°F or below. This coil temperature issensed by the coil temperature sensor mounted near thebottom of the outdoor coil. Once coil temperaturereaches 30°F or below, the coil temperature sensorsends a signal to the control logic of the heat pumpcontrol and the defrost timer will start.After 60 minutes at 30°F or below, the heat pumpcontrol will place the system in the defrost mode.During the defrost mode, the refrigerant cycle switchesback to the cooling cycle, the outdoor motor stops,electric heaters are energized, and hot gas passingthrough the outdoor coil melts any accumulated frost.When the temperature rises to approximately 57°F, thecoil temperature sensor will send a signal to the heatpump control which will return the system to heatingoperations automatically.If some abnormal or temporary condition such as a highwind causes the heat pump to have a prolonged defrostcycle, the heat pump control will restore the system toheating operation automatically after 10 minutes.The heat pump defrost control board has an option of30, 60 or 90-minute setting. All models are shippedfrom the factory on the 60-minute pin. If specialcircumstances require a change to another time, removethe wire from the 60-minute terminal and reconnect tothe desired terminal. The manufacturer'srecommendation is for 60-minute defrost cycles. Referto Figure 15.There is a cycle speed up jumper on the control. Thiscan be used to reduce the time between defrost cycleoperation without waiting for time to elapse.