Bard W24G3DA Installation Instructions Manual

Bard W24G3DA Installation Instructions Manual Manual pdf 50 page image

Manual 2100-631Page 50 of 53FIGURE 19CIRCUIT DIAGRAMS34. PRESSURE SERVICE PORTSHigh and low pressure service ports are installed onall units so that the system operating pressures can beobserved.35. DEHUMIDIFICATION CIRCUITThe dehumidification circuit incorporates anindependent heat exchanger coil in the supply airstream. This coil reheats the supply air after it passesover the cooling coil without requiring the gas burner tobe used for reheat purposes. This results in very highmechanical dehumidification capability from the airconditioner on demand without using gas reheat.The dehumidification refrigerant reheat circuit iscontrolled by a three way valve directing the refrigerantgas to the normal condenser during periods whenstandard air conditioning is required. During periodsof time of low ambient temperature (approximately 65°to 75° outdoor) & high indoor humidity, a humidistatsenses the need for mechanical dehumidification. Itthen energizes both the compressor circuit and the threeway valve, thus directing the hot refrigerant dischargegas into a separate desuperheating condenser circuit,which reheats the conditioned air before it is deliveredto the room. The refrigerant gas is then routed from thedesuperheating condenser to the system condenser forfurther heat transfer. A small orifice inserted betweenthe reheat coil return line and suction line will preventliquid from accumulating in the reheat coil when it isinactive. This drain does not affect the normal operationof the system. A check valve is located in the reheatoil return line. It has a soft spring to hold the ball onthe seat. This will make the method of checking theball freedom with a magnet difficult. Refer to Figure19 for the location of the check valve and drain backcapillary. When the humidistat is satisfied, the systemautomatically switches back to normal air conditioningmode and either continues to operate or turns off basedon the signal from the wall thermostat. The result isseparate humidity control at minimum operating cost.AIR CONDITIONING MODECIRCUIT DIAGRAMDEHUMIDIFICATION MODECIRCUIT DIAGRAM

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