10/04/2007 9
NI802
WarmFlo Controller –
Inside View, Left Board
Remote Sensor
Duct sensor, A-coil not in supply plenum
– the duct sensor (shorter cable, black wire on ST terminal) is
installed approximately 24” above (or airflow distance from element) the Electric Furnace or electric
elements. Drill a ½” hole, approximately plenum center.
If there is not adequate plenum distance, pick the largest distribution duct and install towards the top of
the horizontal duct. Locate, common sense, in the maximum warm air stream.
Duct sensor, A-coil in supply plenum
– the duct sensor (shorter cable, black wire on ST terminal) is
installed on the warm side of the coil and 4” to 6” after the coil. Pick the side which appears to have the
most airflow distribution (facing A-coil) and drill a ½” hole approximately 2” from the side edge.
Again the key is getting this sensor in the maximum warm air stream, the air coming through the A-coil
fins will all be on the edge of the plenum.
Note
: The black tip inside of the white tube is the sensor itself. It must be positioned slightly
sticking out of the white tube. The only purpose of the white tube is physical protection, once it
is installed it is okay to push out the sensor ¼” to ½” to make it more sensitive and faster
responding to the warm air stream.
Outdoor sensor
– extend sensor to an outdoor location properly sampling the outdoor winter
temperature. The north side may pick up too much shading and winds, but the south side should be
avoided unless there is a position which will shade the sun. Install bracket with the sensor tip up (cable
downward).
Use care in selecting location so the sensor does not pick up false temperature from the heat pump
outdoor unit, from refrigerant line sets, dryer vent, reflection off of steel siding, etc. Also do not install
the sensor in a plastic box because it will falsely trap and pick up radiant sun temperature.
Other Sensor Related Comments
The factory supplied OT cable is 25 feet. If additional cable length is required, you must use the
following rules for extending the cable.
Use unshielded (low capacitance, preferred twisted) 3 or 4-wire low voltage cable.
50 feet is maximum.
Do not, under any circumstances, use leftover wires within the thermostat cable going out to
the outdoor unit.
Route the sensor cable making sure you do not crimp, cut, staple, or damage the cable in any
way.
Keep sensor cables at least 12” away from any line voltage wiring, romex, etc.
For easy sensor cable disconnect and reconnect, the WarmFlo board has a plug-in 4-place terminal block.
Before disconnecting, you will notice two red wires are under one screw and two white wires is under the
COM screw. The black wire represents the data information from each sensor and must be connected to
the appropriate OT or ST screw.
The sensor has polarity, is sensitive to wrong voltage, must be protected from static voltage, etc. Do not
cross connect or inadvertently short out sensor wires with power on. Permanent destruct damage may
result.
