Honeywell TH8321 Product Data page 53

TO CHANGE DIFFERENTIAL SETTINGS
1. Select Advanced Options to view/adjust differentials
between all stages.
Fig. 102.
2. Default is Comfort. Adjust differentials as needed.
Fig. 103.
Backup Heat Droop
A Backup Heat Droop is available for any system with 2
heating types. For example:
• Heat Pumps with any type of Backup Heat
• Radiant Heat with any type of Backup Heat
• Hot Water Fan Coil with any type of Backup Heat
The Backup Heat Droop restricts backup heat during the
following conditions:
• Normal Operation
• Manual Setpoint Changes
The options are:
• Comfort – keeps temperature within 1 degree of the
setpoint.
• 2 to 15 °F – Backup heat is not used unless the indoor
temperature drops to the selected Backup Heat Droop.
For example, if the Backup Heat Droop is set to 2 °F
(1.0 °C), the indoor temperature must be 2 °F (1.0 °C)
away from the setpoint before the backup heat turns on.
NORMAL OPERATION
When the Backup Heat Droop is set to Comfort, the
thermostat uses backup heat as needed to keep the indoor
temperature within 1 °F (0.5 °C) of the setpoint. The
Comfort setting is NOT an option on heat pumps with fossil
fuel backup heat.
VISIONPRO® 8000 SMART THERMOSTAT
When the Backup Heat Droop is set to 2 °F or higher,
backup heat is not used unless the indoor temperature
drops to the Backup Heat Droop setting or the Backup Heat
Upstage Timer expires, whichever occurs first. The upstage
timer starts when the highest stage of the previous
equipment type turns on.
MANUAL TEMPERATURE CHANGE
When the Backup Heat Droop is set to Comfort, the
thermostat uses backup heat as needed to keep the indoor
temperature within 1 °F (0.5 °C) of the setpoint. The
Comfort setting is NOT an option on heat pumps with fossil
fuel backup heat.
When the Backup Heat Droop is set to 2 °F or higher, if the
primary heat is making progress as expected, backup heat
will not be used to reach the new setpoint. Set to a higher
number to use less backup heat (a greater difference
between the current indoor temperature and the new
setpoint is required to turn on backup heat). See notes
below.
PROGRAMMED RECOVERY
If the primary heat is making progress as expected, backup
heat will not be used to reach the setpoint of the next
program period. Backup heat is always restricted during a
programmed recovery when the Adaptive Intelligent
Recovery feature is used. See note below.
NOTE: During a programmed recovery (or when the tem-
perature setpoint is changed by the user), the
thermostat waits to turn on the backup heat
depending on system performance, load condi-
tions and how many degrees the temperature set-
point is changed. Backup heat will be used ONLY
when the temperature is not rising quickly enough
to reach the setpoint in a reasonable time.
NOTE: If the backup heat was used in the last 2 hours
because the primary heat was not able to maintain
the setpoint, the thermostat may turn on the
backup heat earlier when the user raises the set-
point. This does NOT apply to heat pumps with
fossil fuel backup heat.
TO CHANGE BACKUP HEAT DROOP SETTINGS
1. Select Basic Options or Advanced Options to
view/adjust Backup Heat Droop settings.
2. Default is Comfort. Adjust differentials as needed.
53
Fig. 104.
33-00096—04