Carrier A07049 Installation Instructions Manual page 40

Cycle Timer
Based on the selection of 2, 4, or 6 cycles per hour, this timer is set to 30, 15, or
10 minutes. This much time must elapse from the start of one cycle before
another cycle can start. It serves to impose the cycles per hour limits. It can be
defeated for one cycle by simultaneously pressing the FAN and UP buttons.
Ten- -Minute Staging Timer
In multistage heating or cooling, this timer prevents any higher stage from
turning on until preceding stage has been on for 10 minutes. When staging
between compressor and electric heat or between compressor and furnace heat,
the time is configurable. The timer is configurable via Option 17. This timer is
overridden if temperature error is greater than 5_F (usually due to a large change
in desired temperature) and equipment stages up in 60 second intervals.
Defrost
Detection of defrost will not work properly if the installer has configured the
O/W2/B output to function as a B output. During heat pump heating, a defrost
signal shall be considered valid if the compressor output is energized and the
defrost signal has been active for less than 15 consecutive minutes. Any defrost
signal present for longer than 15 minutes shall be considered invalid.
Heat pump/fan coil systems shall use this input to:
Detect that defrost is in progress and energize the auxiliary heat to
S
provide homeowner comfort during the defrost cycle
Allow a defrost cycle to run to completion regardless of the system
S
demand
40