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THX9321 PRESTIGE
2.0 AND THX9421 PRESTIGE
NOTE: If humidification and dehumidification are setup
to operate in the same system mode (Heat, Cool,
Off) and you are sensing humidity from one loca-
tion, the thermostat will automatically enforce a
15% deadband between the humidification and
dehumidification settings. The thermostat will
automatically switch between humidification and
dehumidification to maintain the desired humid-
ity level.
If humidification and dehumidification are setup
to operate in the same system mode (Heat, Cool,
Off) and you are sensing humidity from two dif-
ferent locations using a remote wireless indoor
sensor (for example, main level and crawl space),
the thermostat will allow humidification and
dehumidification to operate at the same time, and
there is no deadband between humidification and
dehumidification settings.
Press MENU
Scroll to select DEHUMIDIFICATION
Set humidity to desired
Press to review filter timer
Ventilation
The thermostat can be set for the following ventilation
types: (ISU 10000)
• ERV/HRV
• Passive (Fan Only)
• Fresh Air Damper
Ventilation Control Methods (ISU 10050)
Ventilation can be setup to meet either ASHRAE or
Percent On Time settings. To meet these settings, the
thermostat will ventilate during calls for heat, cool, and
fan. If the required ventilation has not been achieved for
ASHRAE or Percent On Time, the thermostat will force the
ventilation equipment on.
68-0311—07
®
IAQ WITH EIM
• ASHRAE
The thermostat operates ventilation equipment to meet
the ASHRAE 62.2 ventilation standard based on CFM,
number of bedrooms, and square footage of the house.
ASHRAE 62.2 can only be met if the ventilation
equipment is running. If the ventilation equipment is
off for any reason (outdoor ventilation lockouts, set up
to turn Off during Sleep period, turned off by user, etc.),
ASHRAE 62.2 is not met during those times. See ISU
10125 to select a Ventilation Priority.
• Percent On Time
The thermostat operates ventilation equipment based
on a percentage entered in the installer setup (ISU
10120). For example if Percent On Time is set to 50%,
the ventilation equipment will run at random times
during a 1 hour period until it reaches a 50% run time
(approximately 30 minutes). Default setting is 30%.
Range is 10% to 100% in 10% increments.
Ventilation Fan Control (ISU 10060)
• Thermostat Controls Fan
The thermostat turns on the ventilator and the fan
when ventilation is needed.
• Equipment Controls Fan
The thermostat turns on the ventilator when ventilation
is needed. The fan is controlled by the equipment.
Ventilation Priority (ISU 10125)
• Lockouts are Priority
The thermostat places a priority on lockouts versus the
ASHRAE 62.2 ventilation standard. The thermostat will
not run ventilation during the following lockout
conditions (if configured) unless you manually call for
ventilation:
—
Lockout Ventilation during Outdoor Conditions
(ISU 10130)
—
Lockout Ventilation on Humidification or Dehu-
midification Calls (ISU 10140)
—
Lockout Ventilation during "Sleep" (Residential) or
"Unoccupied" (Commercial) program periods.
Note: This option is set by the user on the Ventila-
tion screen in the Menu.
• ASHRAE is Priority
ASHRAE requires additional ventilation following a
long off cycle. The thermostat meets the ASHRAE 62.2
ventilation standard by running additional ventilation
when outdoor conditions are favorable. If ASHRAE
cannot be met when outdoor conditions are favorable,
the thermostat will override the outdoor lockouts and
run ventilation. When using this option, it is
recommended to increase the rate (CFM) of the
ventilation equipment to meet the ASHRAE 62.2
ventilation standard in a shorter run time.
NOTES: ISU 10140 "Lockout Ventilation on Humidifica-
tion or Dehumidification Calls" is not an option
when you select "ASHRAE is Priority".
The ability to lockout ventilation during the
"Sleep" or "Unoccupied" program periods is not
an option when you select "ASHRAE is Priority".
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