THX9321 PRESTIGE
®
2.0 AND THX9421 PRESTIGE
®
IAQ WITH EIM
115
68-0311—02
8.
If Percent On Time was selected for ISU 10050, select
the Ventilation Percent on Time. See Fig. 255.
Fig. 255.
9.
Select the Outdoor Condition Lockouts. See “Ventilation
— Outdoor Condition Lockouts (ISU 10130)” on
page 113 for more information.
When ISU 10125 Ventilation Priority is set to Lockouts
are Priority, or ISU 10050 Ventilation Control Methods is
set to Percent On Time, the thermostat will indicate
whether this meets or may not meet the ASHRAE 62.2
Standard or the Percent On Time setting. See Fig. 256.
When ISU 10125 Ventilation Priority is set to ASHRAE is
Priority, the screen below will indicate the maximum
length of time that ventilation can be locked out over a 21
hour time period. For example, Ventilation Lockout Will
Not Exceed 12.5 hours. The length of time that ventila-
tion is locked out is limited to ensure that the ASHRAE
62.2 Ventilation Standard is met. See Fig. 256.
Fig. 256.
10.
Select whether to lockout ventilation on humidification or
dehumidification calls. This feature is used to help reach
the user's desired humidity level by not allowing the ven-
tilation equipment to run during a call for humidification
or dehumidification. The thermostat will indicate whether
this meets or may not meet the ASHRAE 62.2 Standard
or the Percent On Time setting. See Fig. 257.
NOTE: ISU 10140 “Lockout Ventilation on Humidifica-
tion or Dehumidification Calls” is not an option
when you select “ASHRAE is Priority” at ISU
10125.
Fig. 257.
11.
Select whether to Ventilate on High Indoor Humidity. See
“Ventilate on High Indoor Humidity (ISU 10160)” on
page 113 for more information. See Fig. 258.
Fig. 258.
Control Ventilation Level
1.
Press MENU, then scroll to select Ventilation.
2.
Press Setting to set the operating mode.
• Automatic: Ventilation runs as programmed by the
installer (ASHRAE or Percent On Time).
• Off: Ventilation remains off unless turned on by the
timer or from a Vent Boost Remote.
• On: Ventilation is always on.
3.
Press
or
to run ventilation temporarily. The Tempo-
rary Boost (timer) setting range is 0–180 in 20 minute
increments. To turn Temporary Boost off, set to zero or
press Cancel Temporary Boost.
