Carrier A07049 Installation Instructions Manual page 43

Ten-Minute Staging Timer
Inmultistage heating or cooling, thistimer p revents anyhigher stage f rom
turning o nuntilpreceding stage h as been onfor10minutes. When staging
between compressor and electric heat orbetween compressor and furnace heat,
the time isconfigurable. The timer isconfigurable viaOption 1 7. T his timer i s
overridden if temperature error isgreater than 5 _(usually due toalarge c hange
indesired temperature) and equipment stages upin60 second intervals.
The ten-minute staging timer d oes n otrequire the thermostat tochange toa
higher stage after 1 0minutes. If the system i sable t omeet the demand (maintain
setpoint) itmay not c hange stages after t he 10 minute timer has e xpired. If there
issufficient demand forahigher stage atthe end of10minutes oratany time
after the 10minute timer has e xpired, the thermostat willenergize the next higher
stage.
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
provide homeowner comfort during the defrost cycle
• Allow a defrost cycle to run to completion regardless of the system
demand
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