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FIGURE 21
LVC2 BOARD TERMINAL DESIGNATIONS
24VAC
THERMOSTAT INPUTS;
H1 HEADER
24VDC
VFD INPUTS;
H2 HEADER
4- If there is no thermostat signal, troubleshoot back
toward the thermostat.
5- Check the power LED on the board. See figure 20.
6- If the power LED is not on, check voltage between
LVC2 terminals PC (H2-1) and SD (H2-5). Voltage
should read 24VDC.
7- If voltage does not read 24VDC, disconnect the H2
header from the LVC2 VFD inputs terminal block (to
make sure the LVC2 is not shorting 24VDC supply
from the inverter). Measure the voltage between the
end terminals on the H2 header. If 24VDC is present,
replace the LVC2 board. If no voltage is read,
troubleshoot the VFD.
8- When LVC2 24VAC thermostat blower (G) input and
24VDC power are present, check the LVC2 low and
high speed outputs. The LVC2 uses inverse logic to
enable the blower; 1VDC will be read at the enabled
blower speed terminal. See table 12.
9- If all inputs are correct and the unit still does not
operate as intended, replace LVC2 board.
TABLE 12
LVC2 BOARD BLOWER OUTPUTS
Output
Terminals
Voltage
Blower Operation
RL-SD
1VDC
Low Speed
RH-SD
24VDC
RL-SD
24VDC
High Speed
RH-SD
1VDC
RL-SD
1VDC
Illegal State
(replace board)
RH-SD
1VDC
RL-SD
24VDC
Blower Off
(replace board)
RH-SD
24VDC
