Communicating Control Operation - ComfortNET CTK02AA Installation Manual

Communicating Control Operation

Multi-Stage Time Delay Operation
Your thermostat is designed to determine the optimum time to efficiently activate second stage operation. There is
a time delay algorithm from 0 - 30 minutes depending on the performance of the first stage and simply raising the
temperature in heating or lowering it in cooling will not always force a second stage demand.
EXAMPLE: For the last 2 hours the thermostat is set on 70° and the room temperature is 70° with the equipment using
only the first stage of heat. Since the equipment is keeping the temperature within 1° of set point, the thermostat will
delay second stage for a longer time if you manually raise the temperature or if the room temperature quickly changes.
Once the second stage is activated, the control will cycle second stage sooner the next time there is a difference
between the set point and the room temperature. The net effect of the staging program is that when the first stage is
capable of making temperature the second stage will delay longer. When the thermostat calculates first stage opera-
tion cannot achieve temperature in a reasonable time, the second stage will be activated sooner. This built in function
automatically optimizes the use of additional heating or cooling stages.
Dual Fuel Operation
This feature is for heat pump systems installed in conjunction with a gas furnace.
This control eliminates the need for an additional fossil fuel kit.
The dual fuel set point is adjustable in the Advanced Installer Menu (selectable from 5°F - 50°F – default 30°F) and
is based on feedback from the remote temperature sensor located in the outdoor unit. Above this setting and with
a first stage heating demand the heat pump will be engaged in heating mode. Below this setting or upon a second
stage heating demand the gas furnace will be engaged. Both first and second stage dual fuel operation staging will be
conducted as is outlined in the Multi-Stage Time Delay Operation section above.
14 / Installation Guide ComfortNet HiDef Control System