Circulation function in programmable thermostat

Just wondering if the circulation function in programmable thermostat means that it will turn the fan on 100% of the time when the heat or cooling is on + it will turn the fan on 35% of the time that when the heat or cooling is not on.
Can anyone clarify this?
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umm, Circulation Function may mean Fan Only to simply circulate the air with no heating or coolin?
"Many residential HVAC systems use different fan speeds for the different HVAC functions. For example, the fan speed is lowest for the circulation function, higher for the heating function, and highest for the cooling function."
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lee_houston wrote:

Programmable Portion says:
Circ - fan runs randomly approximately 35% of time. Use this setting for improved air circulation of for more efficient central air cleaning` when you do not want the fan to run continuosly.
Manual Overide Programmable Portion says:
Circ - overides fan schedule. Fan circulates randomly for approximately 35% of time until the auto position is selected.
Does 35% of the time mean when the system is not on cool or heat? I would think the fan would run 100% of the time if any conditioning was happening at all.
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Just spoke with Honeywell.
Apparently, the random 35% running time of the fan is based on a particular schedule. For instance, if heating and/or cooling has been set for the wake period, and then fan has been set to run with the system, the fan will be on 100% of the time while either heating or cooling is on. If during the wake period, the heating or cooling stops AND the conditioning period is less than 35% of total wake period, then the fan will run for up to 35% of the wake period.
This cannot be that accurate as it will require some prediction on the thermostat's part. But, I guess it can help to circulate air when the conditining part is off.
Hope this helps someone out there.
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