Manual 2100-541D
Page 14 of 28
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.
NOTE: The additional LAB (low ambient bypass) relay
is required to prevent heater operation during low
temperature cooling operation.
OPTIONAL COMPRESSOR CUTOFF
THERMOSTAT (See Figures 8 & 9)
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.
FIGURE 9
COMPRESSOR CUTOFF THERMOSTAT WIRING
15 – 20KW 1 PH AND 3 PH
FIGURE 8
COMPRESSOR CUTOFF THERMOSTAT WIRING
4 – 10KW 1 PH – 6 & 9KW 3 PH
