Bard WH421 Installation Instructions Manual

Also see for WH421: Specifications Installation instructions

Manual 2100-399Page 12THERMOSTAT WIRINGCOMPRESSOR CUTOFF THERMOSTAT ANDOUTDOOR THERMOSTATSHeat pump compressor operation at outdoortemperatures below 0° F are neither desirable noradvantageous in terms of efficiency. Since mostequipment at time of manufacture is not designated forany specific destination of the country and most of theequipment is installed in areas not approaching thelower outdoor temperature range, the compressor cutoffsare not factory installed.HEAT ANTICIPATIONBoth of the thermostats in Groups A and B below havea fixed heat anticipator for stage 1 with no adjustmentrequired. Stage 2 has an adjustable anticipator for theW2 connection and fixed for the W3 connection. Boththe W2 and W3 circuits are controlled by the stage 2bulb. The only heat anticipator that needs to bechecked is stage 2 and it should be set to match the loadcarried by the W2 circuit. The normal factory wiringprovides for only on electric heat contactor to becontrolled by W2, and the anticipator should be set at.40A. If special field wiring is done, it is best toactually measure the load but a good role is .40A foreach heat contactor controlled by W2.Outdoor thermostats are available to hold off variousbanks of electric heat until needed as determined byoutdoor temperature. The set point of either type ofthermostat is variable with geographic region andsizing of the heating equipment to the structureUtilization of the Heating Application Data and theheat loss calculation of the building are useful indetermining the correct set points.FIGURE 8COMPRESSOR CUTOFF AND OUTDOOR THERMOSTAT WIRING4 - 10KW 1PH --- 6 & 9KW 3-PH15 - 20KW 1-PH & 3-PHMIS-409TABLE 3THERMOSTAT WIRE SIZEremrofsnarTAV ALF eguaGeriWmumixaMecnatsiDteeFnI55 3.2eguag02eguag81eguag61eguag41eguag215406001061052