6. Operation Flow Chart
Water heating
NO
Safety device triggered
Flow is adjusted
than setting
outlet water temp. less
(1A or more)
abnormality
Flame rod circuit
Outlet thermistor
open or shorted
Inlet thermistor
YES
Fan speed
> 0.5 GPM
YES
NO
normal
Initial check
YES
Hot water demanded
( )
Igniter stops sparking
others:after 2 sec.
1st, 4th, 7th:after 5 sec.
detects > 1A
Flame rod
Igniter sparks
Priority lamp (yellow) lights
Connect power
On/Off button turn ON
Inlet water high
*1
Abnormal combustion
Fan speed
61
14
16
32
open or shorted
31
Inlet thermistor
open or shorted
31
32
71
Fix problem
Fan motor stops
(Flame rod)
(Ignition failure)
11
12
61
72
Stop hot water demand
Turn power Off
Priority lamp turns OFF
Disconnect power
Water flow sensor detects
(target 200 rpm)
(After 60 sec)
open or shorted
Burner On Lamp
Outlet thermistor
Error code stops flashing
90
YES
NO
14
Normal
NO
YES
10
99
Self-diagnosis
Normal combustion
(High-limit switch)
20
99
to more than 10 years
Using terms is equivalent
Main flow control valve
YES
YES
YES
YES
YES
NO
NO
NO
NO
NO
NO
NO
YES
The unit will continue to operature with
the code blinking.
Warning indication
Warning indication
(Fan abnormality)
1
5
10
12
13
15
16
17
9
1
6
5
1 1
6
11
5
6
9
temperature check
Igniter stops sparking
At max BTU, is
goes off
closes
Gas solenoid Valve 3
Primary gas solenoid
valve opens
Gas proportioning valve
opens
Fan motor ON
Burner on lamp
lights
Gas solenoid valve
opens or closes
Primary gas solenoid
valve closes
Gas solenoid valve 1
closes
Gas proportioning valve
closes
Burner On lamp
goes off
closes
Gas solenoid valve 2
closes
Primary gas solenoid
valve closes
Gas solenoid valve 1
closes
(0.5A or less)
not detect a flame
Flame rod does
is too high
Outlet water temp.
Abnormal gas solenoid
valve drive circuit
18
High limit switch
is normal
YES
NO (3rd)
Main flow control valve
moves to initial
position setting
Lightning safety
device normal
NO
YES
of use
YES
10 years or more
NO
Maximum output limited
90
NO
YES
90
possible
Self-diagnosis
Normal combustion
possible
Self-diagnosis
Normal combustion
possible
Overheat prevention
device (Thermal fuse) normal
(Less than 363°F)
control valve operating
Main flow
YES
normal
NO
65
open or shorted
Heat exchanger thermistor
7
33
abnormality
Circuit board
70
(5 times or less)
YES
Extinction
NO
Re-ignition
(8 times or less)
Gas solenoid valve 1
14
closes
Gas proportioning valve
Gas solenoid valve 3
opens
activates
33
Heat exchanger
open or shorted
7
thermistor
*3 When the present fan speed is 500rpm more or less than target speed.
abnormality *3
(as necessary) *2
2
Overheat prevention
device (Thermal fuse)
triggered (363°F or more)
2
Warning indication
Warning indication
8
clogging
Condensate trap
29
4
8
open or shorted
Exhaust thermistor
35
94
29
35
4
8
Total water flow (GPM)
Approx. 28.5
K >
+ water inlet temperature (°F)
Set temperature
K
If the inlet temp is less than 122°F
136°F
Set temp +9°F
Less than 122°F
122°F or more
or if the following statements
about K are true , the inlet temprature
will be normal (YES).
*1
BTU
120,000
Over
70,000
BTU
ON
Over
45,000
BTU
28,000
BTU
Over
16,000
BTU
Over
Gas solenoid
valve 1
Gas solenoid
valve 2
Gas solenoid
valve 3
ON
ON
ON
ON
ON
ON
ON
ON
*2
Over
open or shorted
Exhaust thermistor
is too high
Exhaust thermistor
clogging
Condensate trap
EN18WI30LS / EP18WI30LS
13
Summary of Contents for EN18WI30LS
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