CleaverBrooks CBT - Page 87

750-382
CBT
5-19
Troubleshooting
J.2. Combustion Air
Blower does not run or
does not run to purge
speed (4000 RPM)
Visually inspect blower
cable/harness connec-
tions.
Check that blower
cable/harnesses are
secure on both ends:
3-conductor power
cable to blower power
circuit and 4-conductor
signal cable to Falcon
J2 plug. If either is
found loose and subse-
quently secured, clear
lockout and restart.
Observe Firing rate and
Fan speed on Falcon
status screen -- they
should closely agree
and read approxi-
mately 4000 RPM
during purge.
If Fan speed does not
match Firing rate, see
next step.
Open control panel
door. With volt meter,
check for 115 VAC on
both sides of blower
fuse and at control
panel blower terminal
(T1 on newer boilers;
T46 on older models).
If no power after
blower fuse, replace
blower fuse. Refer to
boiler wiring diagram
for correct fuse size
and type for the boiler.
Clear lockout and
restart.
If no power before
blower fuse, reset cir-
cuit breaker. Clear
lockout and restart.
If measured voltage is
greater than 10V but
less than 104V, check
incoming power, neu-
tral, and ground con-
nections to boiler.
Resolve power wiring
as necessary.
With 115VAC power
connected to blower,
temporarily disconnect
4-conductor blower
signal cable from
blower or Falcon J2
plug. Blower should
run at full speed.
If 115VAC power con-
firmed at blower con-
nection and blower
does not run, contact
factory and/or replace
blower assembly.
K. Lockout 66 Inter-
rupted Airflow Switch
ON
K.1. High negative
draft condition
Check draft presure at
boiler flue outlet (+/-
0.25" w.c. allowed)
Resolve draft condi-
tion (e.g. adjust stack
damper) to near neu-
tral (0" w.c.)
Problem Display Message Possible Cause/Symp-
tom
Diagnostic Check Corrective Measures