Troubleshooting For Abnormalities Due To Scale Build-Up; Water Leak From The Unit - Noritz NR501-OD Service Manual

Troubleshooting for abnormalities due to Scale Build-up

There are three case of inquires about Scale Build-up from users and professional.
Case 1. Water Leak from the unit
Case 2. Hot water is not delivered (The user can not get hot water)
Case 3. Flush the Heat Excahnger regularly (Not displayed the error code)
< Case 1. Water Leak from the unit >
Check to determine which part is leaking.
Is the water leak from the Heat Exchanger?
Ye s
Chec
erent error codes may be caused
Ye s
No
Reconnect electrical power.
(A)
Yes
Is the error code "H#
Yes
Check the code number in the Display Window.
Flashing "H#
Replace the Heat Exchanger*.
Flashing "C #"
Replace the Heat Exchanger*.
Check whether the error code "C #"
Ye s
Check the error code.
No
And then determine the cause and solve the problem.
Flashing "C #"
Replace the Heat Exchanger.
Wa ter leak may be caused by hard water .
The unit is detecting the Scale Build-up in the
Heat Exchanger.
Recommend to install water treatment device
like H2Flow or ScaleShield.
The same trouble may happen after replacing
the Heat Exchanger without installing a water
treatment device.
can not identify
No
ay Window*.
by water leak except for error code "C #".)
# " or "C #"
No
1 2
ay Window?
If the combustion time of the unit is under 600 hours
and detecting the Scale Build-up in the Heat Exchanger,
# "
1 2
the code "H# # " will be displayed after disconnecting
1 2
electrical po wer for 10 seconds.
* ) W ater leak may be caused by hard water .
The unit is detecting the Scale Build-up in
the Heat Exchanger.
Recommend to install a water treatment
devise like H2Flow or ScaleShield.
The same error code and water leaking
may happen after replacing the Heat Exchanger
without installing a water treatment device.
Flashing "CF#"
Reconnect the "blue connector"* f
And then replace the Heat Exchanger.
*To cancel the lockout of Scale Build-up and the error code.The blue connector is located behind
the Circuit Board Plastic Cover and labeled "FLUSH".
Water leak may be caused by hard water .
The unit is detecting the Scale Build-up in the Heat Exchanger
Recommend to install water treatment device like H2Flow or ScaleShield.
The same trouble may happen after replacing the Heat Exchanger without installing a water treatment device.
55
Look for the leaking parts.
Replace the leaking parts.
erent error code except for "C #"
the error code "C #" will be erased by another error code from
the Di swplay Window.
Replace the Heat Exchanger.
The water leak may be caused by poor water .
The same trouble may happen after replacing the Heat Exchanger.
# #
1 2
#
It means Scale detection le vel (1, 2, 3, 4, F).
If the error code from C1# to C4# is displ ayed,
the unit can operate for limited combustion
time (Xt) after reconnecting electrical po wer.
(A)
1 : Xt = 8 hours
2 : Xt = 6 hours
3 : Xt = 4 hours
4 : Xt = 2 hours
F : Reconnecting elctrical po wer is no t
acceptable*.
* When the scale detection level reaches "F",
the unit can not operate. But the le vel comes
ba ck "4" from "F" to reconnect the blue
connector. The blue connector is located
behind the Circuit Board Plastic Cover and
labeled "FLUSH".
.
bustion time of
detecting the Scale Build-u p.
#
= 0, 1, 2, 3, 4, 5, 6 ( x 100 hour)
1
#
= 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 ( x 10 hour)
2
Ex.) If the code "H25 " is displ aye d, it
means 250 hours.
bustion time of
detecting the Scale Build-up.
0 : 0 - 200 hours
1 : 200 - 400 hours
2 : 400 - 600 hours
3 : 600 - 800 hours
4 : 800 - 1000 hours
5 : 1000 - 1200 hours
6 : 1200 - 1400 hours
7 : 1400 - 1600 hours
8 : 1600 - 1800 hours
9 : 1800 - 2000 hours
A : 2000 - 2200 hours
b : 220 0 - 2400 hours
C : 2400 - 2600 hours
d : 2600 - 2800 hours
E : 2800 - 3000 hours
F : 3000 - 3200 hours
r.