Noritz proTOUGH NR981-OD Use and care manual

NR981-OD, NR981-DVC,NR981-SV
NC1991-OD, NC1991-DVC
NR98OD(GQ-2857WX US), NR98DVC(GQ-2857WX-FFA US)
NR98SV(GQ-2857WX-F US)
NC199OD(GQ-2857WZ US), NC199DVC(GQ-2857WZ-FFA US)
SKJ70VC
Rev.05/16
Model Include :
HeatExchangerReplacement
Page1
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Phone866‐766‐7489Fax714‐241‐1196
ServiceRepresentative.Anyunauthorizeduseofthismanualmayresultinvoidingthewarranty.
PleasecontactNoritzTechnicalSupport(866‐766‐7489)foradditionalsupport.
ThisinstructionalmanualisonlyintendedforusebyaqualifiedserviceprofessionalorauthorizedNoritz

Heat Exchanger Replacement Procedure
1. Drain the unit as shown in following procedure 1. Drain the unit as shown in following procedure
Manual Draining
Page 2
Drainage using the Remote Controller
Procedure
* RC-9018M
* RC-7651M
Drain Plugs
Each drain plug might not be
visible if insulation is installed
around the piping.

Heat Exchanger Replacement Procedure
Diagram
Page 3
Procedure
2. Remove Front Cover
(1)Disconnect electrical power to the unit
(2)Turn off gas and water
(3) Remove 4 screws
3. Remove Lightning Protection
(1) DVC model for residential only ; Remove 2 screws
and unplug Remote Controller
that hold Mounting plate for Remote Controller,
(2) Let Remote Controller hang outside of the unit
(3) Remove 2 screws that hold the Lightning
Protection Plate (Whichever the unit is in case
(4) Let Lightning Protection hang outside of the unit
No.2, 3, 4)
Case No.3 (SV model)
Case No.2 (OD model)
(1)
Case No.4 (DVC model for commercial)
Case No.1 (DVC model for residential)
Ex.) OD model

Heat Exchanger Replacement Procedure
Diagram
4. Unplug all wires that attach to the wiring harness
and the body of the water heater
(1) Loosen the wire anchor from left side of the case,
unplug Freeze Prevention Heater
(2) Unplug Thermistor - Heat Exchanger
(3) Remove Cable Tie,
unplug Wiring for Remote Controller
(4) Unplug Freeze Prevention Heaters (4),
Water Servo - Main, - Bypass,
and Thermistor - Hot Water
(5) OD model only ; Unplug wiring for Power supply cord
(6) Remove Cable Tie,
unplug Wiring for Fan Motor, Water Flow Sensor,
Thermistor - Cold Water, -Air Inlet
and Wiring for Manifold Plate
Page 4
Procedure
(1)
(2)
(3)
(4)
(6)
(5)
Cable Tie
Cable Tie

Heat Exchanger Replacement Procedure
Diagram
(7) Unplug wiring for Igniter
(8) Loosen the wire anchor from right side of the case,
unplug High Limit Switch,
SV, DVC model only ; Unplug Freeze Prevention
Heater (2)
(9) Unplug Thermistor-Scale Detection*
(10) Unplug Thermal Fuse (2)
(11) Unplug Flame Rod and Ignition Plug
(12) Remove screw that hold Circuit Board
(13) Let all wires and Circuit Board hang outside of the unit
Page 5
Procedure
(10)
(13)
(7)
(11)
(12)
(8)
(8)
(8)
Thermistor - Scale Detection
(9)
*The following models have "Thermistor
- Scale Detection"
NR98OD(GQ-2857WX US)
NR98DVC(GQ-2857WX-FFA US)
NR98SV(GQ-2857WX-F US)
NC199OD(GQ-2857WZ US)
NC199DVC(GQ-2857WZ-FFA US)
Ex.) SV model

Heat Exchanger Replacement Procedure
Diagram
5. SV, DVC model only ; Remove Case Top Cover
from top of the unit
(1) Disconnect the venting from the unit
(2)SV model only ; Remove 6 screws
and remove 2 Case top Covers of the unit,
Gasket - Exhaust Flue and set aside.
(3) DVC model only ; Remove 2 screws
and remove Case Top Cover of the unit and set aside.
6. DVC model only ; Remove Tube - Metal Back
Pressure Tube
(1) Remove 1 screw on Exhaust box
that attach the tube
(2) Remove the tube from Exhaust box
Page 6
Procedure
(2)
(3)
(2)
Gasket - Exhaust Flue
SV model
SV model
DVC model
DVC model

Heat Exchanger Replacement Procedure
Diagram
7. Remove Manifold Plate
(1) Remove 4 big silver screws on Manifold Plate
that attach the Manifold Plate to Burner
(2) Remove "C" Clamp
(3) Locate inlet pipe to Manifold Plate and push up,
remove the Manifold Plate
8. Remove Water Servo - Bypass
(1) Remove 2 "C" Clamp
(2) Remove Water Servo - Bypass
9. Disconnect a pipe from Water Flow Sensor
(1) Remove "C" Clamp,
disconnect a pipe from Water Flow Sensor
Page 7
Procedure
(1)
(2)
(3)
(1)
Water Servo-Bypass
Water Flow Sensor

Heat Exchanger Replacement Procedure
Diagram
10. Disconnect a pipe from Water Servo - Main
(1) Remove "C" Clamp,
disconnect a pipe from Water Servo - Main
11. Remove the assembly from Case
(1) Remove 2 set screws on the bottom of Burner
(2) Remove 2 set screws near the top of the case
DVC model only ;
Remove 4 set screws near the top of the case
(3) Exhaust Box, Copper Heat Exchanger (CU HE),
Burner, and Fan Motor will come out in one section,
remove from the unit
Page 8
Procedure
(1)
(2)
(1)
(2)
Water Servo-Main
DVC model
SV model

Heat Exchanger Replacement Procedure
Diagram
12. Replacing the gasket
(1) OD model only ;
Remove Gasket on the front of Exhaust Box,
and reinstall Gasket onto new Exhaust Box
13. Remove CU HE
(1) Remove 12 screws holding Burner to CU HE
(2) Separate Burner from CU HE
14. Remove the heat exchanger components from
old heat exchanger and put on new heat exchanger
(1) Front side: Freeze Prevention Heater,
and Thermistor - Heat Exchanger
(2) Right side: High Limit Switch
SV, DVC model only ; Freeze Prevention
Heater (Secure to put Freeze Prevention Heater on
same position)
(3) Back side: Thermistor - Scale Detection*
Remove Packing on CU HE
Remove the small screw(M3×6) on CU HE that
holding Thermistor-Scale Detection
(4) Under side: Freeze Prevention Heater on water outlet
pipe, and Freeze Prevention Heater on water inlet pipe
(Secure to put Freeze Prevention Heater on
same position)
Page 9
Procedure
(4)Under side
(1)
(1)Front side
(2)Right side
Gasket
Thermistor - Scale Detection
Packing
- for holding Thermistor
(3)Back side
*The following models have "Thermistor
- Scale Detection"
NR98OD(GQ-2857WX US)
NR98DVC(GQ-2857WX-FFA US)
NR98SV(GQ-2857WX-F US)
NC199OD(GQ-2857WZ US)
NC199DVC(GQ-2857WZ-FFA US)
Wiring Harness of Thermistor - Scale Detection
The following models have "Thermistor - Scale
Detection"
NR98OD(GQ-2857WX US)
NR98DVC(GQ-2857WX-FFA US)
NR98SV(GQ-2857WX-F US)
NC199OD(GQ-2857WZ US)
NC199DVC
(
GQ-2857WZ-FFA US
)

Heat Exchanger Replacement Procedure
Diagram
(4) Attach Thermal Fuse, 4 Clamps, and Harness Clip
on 4 sides of CU HE, see 4 views of CU HE to
make sure Thermal Fuse is routed correctly
Page 10
Procedure
Front side
Back side
Clamp
Left side
Keep Thermal Fuse straight
Right side
NR981-OD/DVC/SV
NC1991-OD/DVC
Clamp
Back side
NR98OD/SV/DVC(GQ-2857WX＊＊)
NC199OD/DVC(GQ-2857WZ＊＊)
Secure the Thermistor-Scale Detection with screw(M3×6) on CU HE
NOTE ; Only tighten by a hand screwdriver (No Drills). Not need to attach the Packing
(for holding Thermistor - Scale Detection) when replacement.
To hold Wiring Harness of Thermistor - Scale Detection, tie the Wiring Harness
with Harness Clip.
Wiring Harness of Thermistor-Scale Detection
DVC and SV model have 2 Prevention Heaters on bended pipe
Make sure Wiring Harness does not contact with Freeze Prevention
◆Tie "Thermal Fuse" and "High Limit Switch" with Harness Clip
◆Tie "Thermal Fuse", "High Limit Switch" and "Thermistor - Scale Detection"
with Harness Clip
Harness Clip
The end of Insulation tube (Black)
and Inlet Pipe of CU HE are lined up