Page 22
TABLE 1
LED
Status
Indicates
Action
Off
No power to
board.
Check field wiring.
On
Processor error.
Press MCC pushbutton and
hold for three seconds to reset
processor.*
Flashes
Slowly
Normal.
None.
Flashes
Rapidly
Invalid unit DIP
switch selected.
Make sure switches are set
correctly. Refer to figure 5.
Flashes
Rapidly
Simultaneous
heat and cool
demands.
Check thermostat and wiring.
*Press pushbutton and immediately release to override the
4−minute compressor minimum run time.
UNIT TYPE DIP SWITCH (FACTORY−SET)
TGA UNITS
TCA UNITS
THA UNITS
UNUSED
(HEARTBEAT LED WILL FLASH
RAPIDLY IN ERROR)
FIGURE 5
MCC CONTROL BOARD (A45)
FIGURE 6
R W1 Y1 C G BL
OUT
W2
LED
A2
Y4
A2
