Setting The System Key; Setting The Fan Key - Honeywell CHRONOTHERM IV T8665A User Manual

Setting the System Key

Press the System key until the desired
system (Heat, Off, Cool, or Auto) displays.
Heat: The thermostat controls the heating.
Off: Both the heating and cooling are off.
Cool: The thermostat controls the cooling.
Auto: The thermostat automatically changes
between heating and cooling operation,
depending on the indoor temperature.
Thermostat will satisfy system demand
on a first call basis. For example, if
zone 2 (any zone) is calling for heating
and then zone 1 (any zone) asks for
ZONING
cool – the system will satisfy zone 2
before turning on the cool for zone 1.

Setting the Fan Key

Press Fan key until the desired mode
System
(On or Auto) displays:
On: Fan operates continuously.
Auto: Fan operates only when heating
or cooling.
ZONING
before initiating the fan call for this zone.
14
displays when the thermostat is
calling for the fan in this zone.
NOTE: The thermostat may delay
turning on the fan until another zone
has completed its call for heat or cool
Fan
69-1536–3