For models with Honeywell Integrated Control
System w/ Direct Spark Ignition
Thermostat
ca
ll
s
for
heat
.
Combustion
b
l
ower
&
circu
l
ator
start
whi
l
e
the
damper
opens
.
B
l
ower
pre
-
purge
period
of
30
seconds
.
Tria
l
for
I
gnition
.
(5
seconds,
3
tria
l
s)
.
Fl
ame
estab
l
ishing
period
(3
seconds),
gas
va
l
ve
opens,
sparks
from
spark
rod
to
burner
surface
to
ignite
the
gas
.
Burner
on,
f
l
ame
proving
period
(2
seconds)
.
Requires
a
minimum
of
0
.
8
microamp
through
f
l
ame
sense
rod
to
prove
f
l
ame
.
I
f
either
b
l
ocked
vent
safety
switch
contacts
(norma
ll
y
c
l
osed)
or
circu
l
ator
f
l
ow
switch
and
damper
contacts
(norma
ll
y
open)
remain
open
after
being
energi
z
ed,
then
the
ignition
sequence
wi
ll
not
start
and
an
error
code
29
(Safety
switch
circuit
fai
l
ed
to
c
l
ose
or
open)
wi
ll
be
shown
on
the
disp
l
ay
.
Steady
State
Operation
:
Burner
continues
to
operate
unti
l:
Thermostat
circuit
opens,
gas
va
l
ve
c
l
oses,
b
l
ower
continues
to
operate
for
30
second
post
-
purge
period
.
I
f
the
norma
ll
y
c
l
osed
b
l
ocked
vent
safety
switch
opens,
the
gas
va
l
ve
c
l
oses,
the
b
l
ower
post
-
purges,
then
shuts
off
with
error
code
26
disp
l
ayed
in
a
l
ockout
condition
.
Thermostat
satisfied
.
Gas
va
l
ve
c
l
oses,
burner
extinguished
.
B
l
ower
post
purge
for
30
seconds
.
1
2
3
5
6
7
8
4
8
8
