LED should start to
flash which indicates it
is about to turn the
furnace on. When this
LED lights steadily, the
furnace will be signaled
to turn on.
Now, put the
SYSTEM switch to the
OFF position, connect
the air flow sensor
board, and turn to
HEAT again. The
display should show
the temperature. Wait
six minutes and then press both UP/DOWN switches
simultaneously. The display should show AF (Air Flow)
and then a number — this number is the relative air flow
level. Since there is no air flow, the number should be
below 50. Now, use a fan to blow at the sensor. The
number displayed should rise to over 80. Press either
the UP/DOWN button and the display should flash the
pre-set critical air flow level. This critical level can be
changed using the UP/DOWN buttons. After 10
seconds, the display will again show the temperature.
If everything looks okay, then it’s time to install the
■ FIGURE 5
If you are replacing a heating/cooling thermostat, you
should have enough information from Figure 6 to install it
in most systems. Notice the little 24 VAC transformer in
the schematic is part of your heating/cooling system.
Note: Some heat only systems do not have an
external fan lead. In this case, leave G unconnected and
eliminate the Fan switch.
Since SmartStat-Plus has the additional feature of an
air flow monitoring/alert system, you will also need to
place the air flow sensor board in an appropriate location.
A convenient location is in a heating/cooling vent close to
the thermostat. However, if you wish to monitor the dirt in
the air filter, it is best to place it near the air filter itself.
If you don’t have whole house A/C or you only have
whole house A/C (no furnace), you can leave out switch
SW4. SW5 and SW6 are also optional, as is A1.
The source codes are supplied and there are
connectors on the board which allow the software to be
reprogrammed at any time so users can easily modify the
SmartStat-Plus. For instance, some things that can be
changed are the compressor off-time, heater off-time,
CPH, hysteresis, DIP switch options, default settings, and
more. The source code was purposely written so users
don’t need to know the exact workings of the code in
order to modify the SmartStat-Plus. Now you can keep
your cool (and warm!) without worrying. NV
■ FIGURE 6
March 2010 37