Install Instructions

47
Outdoor Reset Control
SECTION XI - Outdoor Reset Control
The appliance setpoint for a heating call can be
fixed or vary with the outdoor temperature. If
the application requires a constant supply tem-
perature from the boiler, the outdoor temperature
sensor should not be connected to the appliance.
If an outdoor temperature sensor is connected to
the appliance, the outdoor reset function is auto-
matically enabled and will vary the CH setpoint
with the change in outdoor temperature.
Mounting the Outdoor Sensor
1. Remove the front cover and mounting
screws / anchors from the sensor enclosure.
2. When mounting the enclosure, the exterior
wall selected should represent the coldest
outdoor temperature. Typically a northern
or northeastern wall will suit most build-
ings. A southern facing wall may suit build-
ings that have large glass walls or windows
on the southern face.
3. Ensure the sensor enclosure is shielded
from direct sunlight or the effects of heat or
cold from other sources (exhaust fans,
appliance vents...) to prevent false temper-
ature sensing.
4. Mount the sensor enclosure at an elevation
on the exterior wall to prevent accidental
damage or tampering.
5. Avoid mounting the enclosure in areas sub-
jected to excessive moisture.
6. Once an area on the exterior wall has been
determined, to affix the enclosure use the
enclosure as a template to mark the location
of the mounting screws.
7. Using a 3/16” [5 mm] drill bit, drill 2 pilot
holes on the marked locations.
8. Tap the enclosed plastic anchors into the
pilot holes. Use care not to damage the
anchors.
9. Mount the sensor enclosure using the
screws provided.
Wiring the Sensor
1. Route two 18 gauge wires through the seal
gasket. Connect the wires to the sensor ter-
minals 1 and 2.
2. Route the sensor wire back to the CHAL-
LENGER, ensuring the wires are not run
parallel to telephone or power cables.
If the sensor wires are located in an area
with sources of potential electromagnetic
interference (close to 120 V wiring) the
sensor wires should be shielded or the
wires should be routed in a grounded
metal conduit. If using shielded cable,
the shielding should be connected to the
common ground of the appliance.
3. Connect the sensor wires to the outdoor sen-
sor terminals 9 and 10 on the low voltage X4
connector terminal strip located at the con-
trol on the swing out panel (see appliance
wiring diagram, Fig. 16 page 27).
NOTICE
Sensor Enclosure
Plastic Anchors (2)
Seal Gasket
Front Cover
M
ounting
Screws
(
2)
Fig. 22: Sensor Enclosure and Components