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©2021 Micro-Air Corp
June 18, 2021, revision 1.5
Appendix C: 8430-331 wiring
Table 5
Table 5 shows the wiring functions used for this model thermostat. Option B must be selected in
the settings’ switches menu. Only two heating zones are possible in this configuration.
Yellow and green
are used to turn on single stage furnaces for zones 1 and two respectively. This can be used in Aqua hot
systems as well to turn on each of the two zones for heating.
Two stage furnaces like certain suburban models use the orange and white wires to turn on the
high furnace fan and high gas valve. This feature activates high furnace if the ambient temperature is
more than four degrees below the set point.
Original
thermostat wire
color
Micro-Air harness
color
Function
Factory harness color
(Provided to write in your
color)
Purple
Purple
Signal 1
Black
Black
Signal 2
Green
Green
Zone 2 On
White
White
Zone 1 High
Blue
Blue
Ground in
Red/White stripe
Red/White stripe
+12 VDC out
Red
Red
+ 12 VDC in
Blue/White stripe
Blue/White stripe
Ground out
Orange
Orange
Zone 2 High
Yellow
Yellow
Zone 1 On