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If COMM LED does not l ight w ithin p roper time p eriod and status
code i sdisplayed,
1.Check s ystem wiringto besureUI is powered and
connections
are made AtoA,BtoB,etc. and wiring isnot
shorted. Mis-wiringor shorting of the ABCD
communications
wiringwill not allow successful
comnmnications.
NOTE: Shorting
ormis-wiring
low-voltage
system
wiring w ill n ot
cause damage
tounit c ontrol orUIbut m ay cause low voltage fuse
toopen.
C.Indoor F an Motor ( IFM) T roubleshooting
The indoor fanis driven b y anElectronic Computated
Motor
(ECM) motor which c onsists
oftwo parts: the control module and
the motor winding s ection. Donotassume
motor ormodule is
defective
if itwillnot s tart. Use t he designed-in
LED information
aids and follow troubleshooting
steps d escribed
below before
replacing
motor control module orentire m otor. Motor control
module isavailable
as areplacement
part.
VERIFY MOTOR WINDING S ECTION
ELECTRICAL
SHOCK H AZARD
Failure
to follow this warning
could result in personal
injury
or death.
After disconnecting
power from the ECM motor, wait at least
5 minutes
before
removing
the
control
section.
Internal
capacitors
require time to discharge.
Before proceeding
to replace a motor control module:
1. Check motor winding
section to be sure it is functional.
2. Remove
motor control module
section and unplug
winding
plug. Motor shaft should turn freely, resistance
between
any
two motor leads should
be similar
and resistance
between
any motor lead and unpainted
motor
end should
exceed
100.000
ohms.
3. Failing
any of these
tests,
entire
ECM
motor
must
be
replaced.
4. Passing
all of the tests, motor control
module
alone can be
replaced.
[
seo-2
seo-1
o
p,
Fig. 14 - Detail of Fan Coil Board
A03169
OO
O
OO
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rq
UTILITY RELAY
UTILITY
SIGNAL
OPEN
RELAY
.4Z[] o
"@ o
9
OO
O
OO
'I if' P'l,
w
t3081_
Liquid
Line
So[enokt
@
* SUPPLIED
BY UTILITY
PROVIDER
A05247
Fig. 15 - 2-Stage
HP/AC
Control
Board
13
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