Install Instructions

1110
90-1203B
CONTROL BOARD
COVER
KNOB
BASE PLATE
RETURN DUCT
RETURN
DUCT
SHEET METAL
PLATE
CUT OPENING IN
RETURN DUCT
SHEET METAL PLATE
GASKET
SCREW (x2)
INSIDE OF
RETURN
DUCT
STEP 2: Determine Location for and Mount Outdoor
Temperature Sensor
The location of the Outdoor Temperature Sensor must meet
these three requirements:
1. Must be mounted on North, East or West side of house out of
direct sunlight.
2. Must be at least 3 feet from all exhaust vents.
3. Must be above expected snow line (see Figure F).
Incorrect humidity levels will result if these requirements are not
met.
Secure sensor bracket with a #8 galvanized screw.
Figure F
NORTH, EAST
OR WEST SIDE
OF HOME
OUTDOOR
TEMPERATURE
SENSOR
SENSOR
BRACKET
SENSOR
ABOVE EXPECTED
SNOW LINE
OUTDOOR
TEMPERATURE SENSOR
LEADS
90-998
NOTE: A convenient way to get the Sensor wire outside is to
make use of unused wires running to the A/C condensing unit
(if applicable). Other ways are to use existing holes for Cable TV
lines, telephone lines, A/C lines, etc. Read all equipment
instructions beforehand for possible conflicts and warnings.
Figure E – Fiber Board Duct Mount