Bard T24H1 Installation Instructions Manual

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Bard T24H1 Installation Instructions Manual Manual pdf 14 page image

Manual 2100-541DPage 14 of 28OPTIONAL OUTDOOR THERMOSTATAPPLICATIONSSince most equipment at the time of manufacture is notdesignated for any specific destination of the countryand are installed in areas not approaching the loweroutdoor temperature range, outdoor thermostats are notfactory installed as standard equipment, but are offeredas an option. There are also different applications forapplying outdoor thermostats. The set point of eithertype of outdoor thermostat application is variable withgeographic region and sizing of the heating equipmentto the individual structure. Utilization of the heatingApplication Data, and the heat loss calculation of thebuilding are useful in determining the correct set points.NOTE: The additional LAB (low ambient bypass) relayis required to prevent heater operation during lowtemperature cooling operation.OPTIONAL COMPRESSOR CUTOFFTHERMOSTAT (See Figures 8 & 9)Heat pump compressor operation at outdoortemperatures below 0°F are neither desirable noradvantageous in term of efficiency. An outdoorthermostat can be applied to take the mechanicalheating (compressor) off line, and send the(compressor) signal to energize electric heat in its place(to make electric heat first stage heating). This can alsobe applied to bank the quantity of available electricheat. For example: A heat pump operates with 10KWsecond stage heat – once the outdoor thermostat hasswitched then operates 15KW without the compressoras first stage heat.FIGURE 9COMPRESSOR CUTOFF THERMOSTAT WIRING15 – 20KW 1 PH AND 3 PHFIGURE 8COMPRESSOR CUTOFF THERMOSTAT WIRING4 – 10KW 1 PH – 6 & 9KW 3 PH