H
ea
te
r
B
ac
kf
la
sh
es
G
as
TT
hr
ou
gh
In
je
ct
or
BB
od
y
Ai
r I
In
le
t.
24
Pr
ob
le
m
44
Is Inner
Cone Crack
ed
or Damaged?
R
eplace Combustion Cones.
Ye
s
No
Are
Inject
or
Body
, Main Burner
Orif
ice, V
enturi T
ube,
or Inner Cone Par
tially
Plugged with
Debris?
Clean These Areas.
Is Pr
oper
Gas Pressure
Being Supplied t
o
the Heat
er?
Check f
or Pr
oper
Gas Pressure.
Pr
oper Pressure at
High Heat Should
R
ead 5 PSIG.
Ye
s
No
No
Pr
ob
le
m
55
H
ea
te
r D
D
oe
s N
N
ot
R
et
ur
n B
B
ac
k t
to
Lo
w
HH
ea
t.
Does
Main Burner Shut Of
f
When Thermostatic Head is
Set Belo
w R
oom
Te
m
perature?
R
emo
ve
Thermostatic Head fr
om Modulating V
alv
e Assembly:
A.
If Heat
er R
eturns t
o Lo
w Fire When y
ou Push Do
wn on Plunger Pin of V
alv
e,
R
eplace Thermostatic Head/Sensor Assembly
.
B.
If Heat
er Still Does No
t Cy
cle t
o Lo
w Fire, the Modulating V
alv
e is Sticking and
Should be R
eplaced.
Combustion Cone Kits
Par
tN
umber
24
21
3
