OPTIONAL OUTDOOR THERMOSTAT APPLICATIONS
Since most equipment at the time of manufacture is not designated for any specific destination of the country and are installed in areas not approaching the lower outdoor temperature range, outdoor thermostats are not factory installed as standard equipment, but are offered as an option. There are also different applications for applying outdoor thermostats. The set point of either type of outdoor thermostat application is variable with geographic region and sizing of the heating equipment to the individual structure. Utilization of the heating Application Data, and the heat loss calculation of the building are useful in determining the correct set points.
Temperature and Humidity Controller
•Limit minimum outdoor temperature for cooling option.
•Limit minimum outdoor temperature for heat pump option.
•Inhibit electric heat operation for heat pumps above selected outdoor temperature.
Thus, not requiring the optional compressor
OPTIONAL COMPRESSOR CUTOFF THERMOSTAT (See Figures 11 and 12)
Heat pump compressor operation at outdoor temperatures below 0°F are neither desirable nor advantageous in term of efficiency. An outdoor thermostat can be applied to take the mechanical heating (compressor) off line, and send the (compressor) signal to energize electric heat in its place (to make electric heat first stage heating). This can also be applied to bank the quantity of available electric heat. For example: A heat pump operates with 10KW second stage heat – once the outdoor thermostat has switched then operates 15KW without the compressor as first stage heat.
NOTE: The additional LAB (low ambient bypass) relay is required to prevent heater operation during low temperature cooling operation.
FIGURE 11
COMPRESSOR CUTOFF THERMOSTAT WIRING
4 & 10KW 1 PH — 6 & 9KW 3 PH
FIGURE 12
COMPRESSOR CUTOFF THERMOSTAT WIRING
15KW 1 PH & 3 PH
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