Operation Flow Chart - Noritz NR50-OD Service Manual

6. Operation Flow Chart

NR50-OD / NR66 (-SV,-OD) / N-0531S (-OD), NR71 (-SV,-OD) / N-0631S (-OD)
Water Heating
On/Off button turn ON
Priority Lamp (Yellow) Lights
(With remote controller)
2
3
6
7
8
9
10
11
12
*2
NR50-OD
a b
2.9 GPM 1.8 GPM
(81,000BTU/h) (53,000BTU/h)
NR66/N-0531S
a b
3.5 GPM 1.9 GPM
(99,000BTU/h) (56,500BTU/h)
14
NR71/N-0631S
a b
4.4 GPM 2.4 GPM
(126,000BTU/h) (73,500BTU/h)
15
NO
Connect power
*Water control valve opens fully
NO
Current leakage safety
device normal
YES
10 years or more
of use
YES
Maximum output limited
Self-diagnosis NO
Warning indication
Normal combustion
possible
10
YES
Self-diagnosis
Normal combustion
possible
YES
1
NO
Thermal fuse normal
YES
Hot water demanded
NO
Water flow sensor detects
> 0.5 GPM
YES
NO
Initial check
normal
YES
*1
Inlet water high NO
*1
temperature check
Normal
If the inlet temp is less than 122°F
YES
or if the following statements
about K are true , the inlet temprature
will be normal (YES)
Fan motor
ON
fan speed
(After 60 sec)
NO
target 200 rpm
YES
Igniter sparks
Primary gas solenoid
valve opens
Gas solenoid valve 1
opens
Gas proportioning valve
opens
( )
1st, 4th, 7th: after 5 sec.
others: after 2 sec.
NO
Flame rod
detects > 1 μA
YES
Igniter stops sparking
Burner On lamp
*NR71/N-0631S (-OD) Only
lights
Igniter stops sparking
NO
Hot water capacity
> a *2
YES
Hot water capacity
> b *2
Gas solenoid valve 2
opens
14
Gas solenoid valve 2
opens
At max BTU, is
Gas solenoid valve 1
NO
outlet water temp. less
closes
than setting
YES
Flow control valve activates
Flow is adjusted
Safety device triggered
YES
Warning indication
The unit will continue to operature with
the code blinking.
NO
Self-diagnosis
NO
Normal combustion
possible
YES
Warning indication
90
NO
3
Inlet thermistor
open or shorted
4
Outlet thermistor
open or shorted
Circuit board
abnormality
Abnormal gas solenoid
valve drive circuit
5 Flame rod circuit
abnormality
(1μA or more)
Approx. 35.7
water inlet temperature (°F)
Total water flow (GPM)
127 °F 127 °F
Set temperature
136 °F Set temp +18 °F
K
YES
Re-ignition NO
(8 times or less)
YES
Extinction NO
(5 times or less)
YES
13
NO (3rd)
High limit switch
is normal
Primary gas solenoid
valve closes
Gas solenoid valve 1
closes
Gas proportioning valve
closes
Gas solenoid Valve 2
closes
Burner On Lamp
goes off
NO
YES
14
16
1
Thermal fuse
triggered
(363 °F or more)
5 4
Flame rod does
Outlet water temp.
not detect a flame
is too high
(0.5 μA or less)
*3 When the present fan speed is 500rpm more or less than target speed.
44
Fix problem
Disconnect Power
Priority lamp turns OFF
Error code stops flashing
Turn Power Off
90
(With remote controller)
99
14
Stop hot water demand
31
32
70
71
72
Fan motor stops
(Ignition failure)
11
(Flame rod)
12
(High-limit switch)
20
(Fan abnormality)
61
Primary gas solenoid
valve closes
Gas solenoid valve 1
closes
Gas solenoid valve 2
closes
Gas proportioning valve
closes
Burner On lamp
*NR71 (-SV,-OD)/
goes off
N-0631S (-OD) Only
31 61
32 90
3 7
Fan speed
Inlet thermistor Using terms is equivalent
abnormality
open or shorted to more than 10 years
*3
4
Outlet thermistor
Abnormal combustion
open or shorted
99