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AWI/TWI Troubleshooting Chart
Caution: Read page 29 before attempting to use this chart
Thermostat
calls for heat
Circulator
start?
120 volts
at L1&L2?
120 volts at
C1&C2?
N
N
*Pow e r of f
*Blow n fuse or
tripped breaker
*Mis w ired or
loose electrical
connection in
120V line
Remove t'stat or
zone valve end
sw itch w ires from
T&TV terminals on
L8148E. Install
temporary jumper
across terminals T
and TV.
Does
circulator
run now ?
*Def ec tiv e
L8148E-see
Note 6 on page
29.
*Loose connection in t'stat or
zone valve end switch wiring
*Def ective t'stat or zone valve
end switch
*T'stat or zone system
misw ired-consult t'stat or
zone valve manufacturer's
instructions
Vent
damper
open?
24 volts
across B and R
(limit sw itch) in
L8148E ?
*Boiler off on
limit
*Def ec tiv e
high limit.
24 volts
betw een pins
1&4 (blue&yellow )and
2&4 (orange&yellow ) on
damper end of damper
harness? See
Note 7 on page 29.
* Loose
connection
betw een
damper
harness and
L8148E
*Def ec tiv e
damper
harness.
* Def ectiv e
L8148E
*Obstruction in
path of damper
blade
*Def ec tiv e
damper motor
*Loose
connection
betw een damper
harness and
damper
Y
START
24 volts
across
T&TV?
120 volts
across
terminals at
circulator?
*Seized or
defective
circulator
*Bad electrical
connection
betw een C1 or
C2 and
circulator
N
Y
N
Y
N
Y
Y
Y
N
N
Y
N
Y
Y
N