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Heater System Solving Guide
FAUL
T CODE THUMBNAILS –
PAGE
F 8
FAUL
T CODE THUMBNAILS –
PAGE
F 8
Heater System Solving Guide
Fault Code Thumbnails HF
NEW
: Gas V
alve F
ault or OLD
: Heater Flame Sensing F
ault
F
AULT
C
ODE
T
HUMBNAILS
HF
F
LAME
P
RESENT
WITH
G
AS
V
ALVE
C
LOSED
/ H
EATER
F
LAME
S
ENSING
F
AULT
UHS
IDL2
ED2
IDL
HF
H
EATER
F
LAME
S
ENSING
F
AULT
IDL, ED2
P
ARTS
T
HAT
M
AY
B
E
N
EEDED
• Ignitor / Flame Sensor
• Control Module / Ignition Board
D
IAGNOSTIC
S
EQUENCE
A. Check all wiring and connections for Flame sensor.
B. Replace flame sensor (IDL) or ignitor (ED2).
C. Replace control module/ignition board if problem still exists.
HF
F
LAME
P
RESENT
WITH
G
AS
V
ALVE
C
LOSED
UHS, IDL2
P
ARTS
T
HAT
M
AY
B
E
N
EEDED
• Gas Valve
If flame is sensed without the gas valve energized, the control will go
into lockout.
D
IAGNOSTIC
S
EQUENCE
• SHUT OFF GAS TO HEATER IMMEDIATELY.
• The gas valve is defective and needs to be replaced.
RIGHT:
HF
INDICATES
A
F
LAME
S
ENSING
F
AULT
ON
OLDER
MODELS
(IDL, ED2)
BELOW:
HF
INDICATES
A
G
AS
V
ALVE
F
AULT
ON
NEWER
MODELS
(UHS, IDL2)