Result
Cause
Remedy
How to check
Phenomenon
2
D. Display「A3」
Failure of overheat protection
Replace overheat protection
Disconnection of overheat
protection cord.
Replace overheat protection cord
Lack of burner packing
Add burner packing
Deterioration of burner packingReplace burner packing
Failure of burner controller.
Replace burner controller
E.
Display「A4」
※Tip-over detector operation.
Failure of tip-over switch
cord
Replace tip-over switch cord
Failure of burner controller
Replace burner controller
F. Display「A5」
Does not rotate or it move slowly
Combustion fan is locked
Cancel the lock or replace combustion fan
DC 170V
Failure of combustion fan
Replace combution fan
DC 0V
Failure of burner controller
Replace burner controlller
G. Display「A6」
Lower than AC70V
Supplied voltage is too low
Operate with appropriate power source
Failure of burner controller
Replace burner controller
H. Display「HV」
Measure the voltage of AC outlet
More than AC 145V
Supplied voltage is too high
Operate with appropriate power source
Failure of burner controller.
Replace burner controller
I. Display「A7」
Failure of burner controller.
Replace burner controller
3
Display「A1」
A. Fuel pump does not operate at all.
∞Ω
Failure of fuel pump.
※High voltage detection.
「A7」is not displayed
(A ambient temperature is displayed)
Disconnection of fuel pump
connector
「A3」is not displayed
(A ambient temperature is displayed)
Plug connector (CN11) firmly
Disconnection of overheat
protection connector.
Plug connector (CN3) firmly
Normal indication after 3
consecutive misfire
Plug connector (CN11) firmly
Replace tip-over switch
※When overheat protection is operated
Plug connector (CN5) firmly
Disconnection of fuel pump
connector
-
※Low voltage stop.
Standard: black-black : Conduction in horizontal(0Ω) ⇒
Figure3 (P.17)
※3 consecutive misfire.
※Combustion fan abnomality detection .
Plug connector (CN1) firmly
「A5」is not displayed
(A ambient temperature is displayed)
standard: AC 120V ⇒ Figure4 (P.17)
「A6」is not displayed
(A ambient temperature is displayed)
「A3」is not displayed
(A ambient temperature is displayed)
Replug in combustion fan connector (CN 3) and then
turn on
Replug in tip-over detector connector (CN 11), and
then turn on
standard: AC 120V ⇒ Figure 4 (P.17)
Unplug the fuel pump (CN 5) from burner controller,
then measure resistance values
Replug in power cable(CN1), and then turn on
Replug in the fuel pump connector (CN 5), and then
turn on
Measure the voltage of AC outlet
Turn off the operation switch, and then plug the power
cable again
※When it does not correspond to the above content
※When it does not correspond to the above content.
※When it does not correspond to the above content
Measure the voltage at CN3 terminal on burner controller
Unplug tip-over detector connector (CN 11),
and then check lead with multimeter
Confirmation of burner packing ⇒ Figure15 (P.23)
※When it does not correspond to the above content
「A1」is not displayed
(A ambient temperature is
displayed)
※When it does not correspond to the above content
Replug overheat protection connector (CN 11) , and
then turn on
The heater does not ignite.
Unplug overheat protection connector (CN 11), and
then check conduction with multimeter
The heater does not start.
Standard: red-red : Conduction(0Ω) ⇒ Figure3
(P.17)
Turn the combustion fan by hand
standard: DC 170V ⇒ Figure4 (P.17)
It does not conduct when operation
switch is turned on(∞Ω)
(Overheat protection is not
detected)
It does not conduct when operation
switch is turned on(∞Ω)
(Overheat protection is detected)
Disconnection of tip-over
connector
Failure of tip-over switch
Disconnection of combustion fan
connector.
Disconnection of power
source connector
It does not conduct in horizontal
Replace pump
standard: blue-blue：about 88Ω ⇒ Figure3 (P.17)
9
