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temperature error is greater than 5_ (usually due to a large change in desired
temperature) and equipment stages up in 60 second intervals.
The ten - minute staging timer does not require the thermostat to change to a higher
stage after 10 minutes. If the system is able to meet the demand (maintain setpoint)
it may not change stages after the 10 minute timer has expired. If there is sufficient
demand for a higher stage at the end of 10 minutes or at any time after the 10
minute timer has expired, the thermostat will energize 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 h eat 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 b e considered invalid.
Heat pump/fan coil systems shall use this input to:
S Detect that defrost is in progress and energize the auxiliary heat to pro-
vide homeowner comfort during the defrost cycle
S Allow a defrost cycle to run to completion regardless of the system
demand
Three- Minute Minimum on Time
In normal operation, when a stage turns on, it will not turn off for a minimum of 3
minutes. If the setpoint is changed, this timer is canceled, allowing the equipment to
turn off immediately when the demand is removed.
Heat/Cool Setpoints (Desired Temperature)
A minimum difference of 1_ and maximum of 6_ is enforced between heating and
cooling desired temperatures. This is done by allowing 1 setting to “push” the other,
to maintain this difference. This difference is adjustable via Configuration Option
11.
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