13
LED
LED Status
Indication
Possible Causes
Corrective Action(s)
Notes & Cautions
Off
x
Normal condition
x
None
x
None
x
None
1 Flash
x
Communications
Failure
x
Communications Failure
x
Depress Learn Button
x
Verify that bus BIAS
and TERM dipswitches
are in the ON position.
x
Depress once quickly
for a power-up reset
x
Depress and hold for 2
seconds for an out-of-
box reset
Red
Communications
LED
2 Flashes
x
Out-of-box reset
x
Control power up
x
Learn button depressed
x
None
x
None
Off
x
No power
x
Communications error
x
No power to modular
blower
x
Open fuse
x
Communications error
x
Check fuses and circuit
breakers; replace/reset
x
Replace blown fuse
x
Check for shorts in low
voltage wiring in
modular blower/system
x
Reset network by
depressing learn button
x
Check data 1/ data 2
voltages
x
Turn power OFF prior
to repair.
x
See Network
Troubleshooting
section.
1 Steady
Flash
x
No network found
x
Broken/ disconnected
data wire(s)
x
Modular blower is
installed as a legacy/
traditional system
x
Check communications
wiring (data 1/ data 2
wires)
x
Check wire connections
at terminal block
x
Verify modular blower
installation type
(legacy/ traditional or
communicating)
x
Check data 1/ data 2
voltages
x
Turn power OFF prior
to repair
x
Verify wires at
terminal blocks are
securely twisted
together prior to
inserting into terminal
block
x
See Network
Troubleshooting
section
Rapid
Flashing
x
Normal network
traffic
x
Control is “talking” on
network as expected
x
None
x
None
Green Receive
LED
On Solid
x
Data 1/ Data 2 miss-
wire
x
Data 1 and data 2 wires
reversed at modular
blower, thermostat, or
CT™ compatible
outdoor AC/HP
x
Short between data 1
and data 2 wires
x
Short between data 1 or
data 2 wires and R
(24VAC) or C (24VAC
common)
x
Check communications
wiring (data 1/ data 2
wires)
x
Check wire connections
at terminal block
x
Check data 1/ data 2
voltages
x
Turn power OFF prior
to repair
x
Verify wires at
terminal blocks are
securely twisted
together prior to
inserting into terminal
block
x
See Network
Troubleshooting
section
Communciations Status LED’s
Summary of Contents for MBVC
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