Control Signals To The Furnace - Mitsubishi Electric PAAA18AA1 Installation Manual

15.5. Control signals to the furnace

Control signals to the furnace are the standard thermostat control signals R, C, W1, W2, Y/Y2 and G/Y1.
Line/
Termi-
nal/
Signal
R Provides 24VAC power from the furnace to the relay board and a limited number of
devices connected to the relay board (required AC input voltage range: 23 V
30 V ).
RMS
C The 24VAC common wire between the furnace and the relay board.
W1 First stage of furnace command line from the relay board to the furnace.
W2 Second stage of furnace command line from the relay board to the furnace. W2 cannot
be ON unless W1 is already ON.
G/Y1 For 1‑speed configuration (Mode 23 = 1), connect this signal to G of the furnace.
For 2-speed configuration (Mode 23 = 2), connect this signal to G and Y1of the furnace.
The G/Y1 signal is energized in Cool, Dry, Heat or Fan modes whenever the fan is turned
on. This signal is also energized, as configured, in coordination with the humidifier and
ERV/HRV.
Y/Y2 For 1-speed configuration (Mode 23 = 1), connect this signal to the Y connection on the
furnace. In this configuration, the Y/Y2 signal turns on when fan is requested while in
Cool mode or Heat mode using the heat pump.
For 2-speed configuration (Mode 23 = 2), connect this signal to Y2 on the furnace. In this
configuration, the Y/Y2 signal turns on as follows:
• In Fan mode, Cool mode or Heat mode with heat pump when high speed fan is
requested.
• In Auto Fan
between room temperature and set point temperature is more than or equal to 2°
C. The signal goes back to low speed when the temperature difference is less than 1°
C.
• In Auto Fan
the difference between room temperature and set point temperature is more than or
equal to 1° C for 3 minutes. The signal goes back to low speed when the temperature
difference is less than or equal to 0.5° C.
1
Requires PUZ/PUY
To operate with the PAA unit, furnaces must have four minimum connections: R, C, W and G.
• On furnaces that only have a W and do not have a W2, connect W1 from the relay board to the W of the
furnace and make no connection with the W2 signal wire.
• On furnaces that do not have Y, configure for 1‑speed mode and make no connection with the Y/Y2
signal wire. On furnaces that have Y (but not Y2), configure for 1‑speed mode and connect G/Y1 to G of
the furnace and Y/Y2 to Y of the furnace.
• On furnaces that have Y1 and Y2, configure for 2-speed mode and connect G/Y1 to G and Y1 of the
furnace and Y/Y2 to Y2 of the furnace.
Specifications are subject to change without notice.
PAA-A18, 24, 30, 36, 42AA1/BA1/CA1
Usage
1
and Cool mode, the signal goes to high speed when the difference
1
and Heat mode with the heat pump, the signal goes to high speed when
83
to
RMS
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