Noritz NR501-OD Service Manual page 53

Error Codes
Display Remote
Window Controller
Combustion abnormality
99 99
(Unit is locked)
<The occurrence condition for error code 901 and 99 >
Gas
Model Name
Maintenance Monitor
type
Initial Fan Speed Correction
NG
NRC711-OD 108%
LP
NG
NRC711-OD
LP
NG
NRC711-DV
LP
NG
NRC711-OD
LP
NG
NRC711-DV
LP
Manifold Gas Pressure Adjustment
NRC711-DV
NRC711-OD
Unit Conditions
48
Period of use
110%
The life of the
110%
unit is not close.
104%
110%
The life of the
unit is close.
104%
53
Description
<Condition of occurrence for error code 99>
When the Unit has begun to operate,
- Air inlet for blockage or obstruction
- Exhaust for blockage or obstruction.
And the li fe of the unit is close.
It is the life of the unit. The unit is locked.
Basically, replace the Unit.
Error
Unit operation
Code
Warning indication.
Unit continue operation.
901
Unit is locked.
99
3.05
3.10
3.55
3.60
2.75
3.45
1.05
1.05
1.20
1.20
0.95
1.20