NORITZ NR662 Series Heat Exchanger Replacement User Manual
- October 30, 2023
- NORITZ
Table of Contents
NORITZ NR662 Series Heat Exchanger Replacement
Product Information
The NR501-OD and NR662-OD series heat exchanger replacement is a procedure only intended for use by a qualified service professional or authorized Noritz Service Representative. Any unauthorized use of this manual may result in voiding the warranty. The product is manufactured by Noritz America Corporation and is located at 11160 Grace Avenue, Fountain Valley, CA 92708. For additional support, please contact Noritz Technical Support at 866-766-7489.
Procedure
Please follow the steps below to replace the heat exchanger:
Step 1: Remove front cover and disconnect electrical power, gas, and water
- Remove the front cover
- Disconnect electrical power to unit
- Turn off gas and water
- Remove four screws
- Remove drain two valves and drain the unit completely
- Remove the cover – circuit board
Step 2: Disconnect connectors from the circuit board and remove the ground wire and circuit board
- Disconnect the connectors from the circuit board
- Remove two ground wires
- Remove the circuit board; there is a screw on the middle-upper of the circuit board. Let the circuit board hang outside of the unit
Step 3: Unplug all wires that attach to the wiring harness and the body of water heater
- Unplug Flame Rod and Ignition Plug
- Loosen the cable tie and unplug the freeze prevention heater, thermal fuse
- Unplug the high limit switch and the thermistor – heat exchanger
- Unplug all wires that attach to the wiring harness except water servo – main
Step 4: Remove manifold plate
- Remove three big silver screws on the manifold plate that attach the manifold to the burner
- Remove two smaller silver screws from the manifold plate that attach the manifold to the gas valve
- Remove manifold plate and unplug the connector from gas solenoid valves
Step 5: Disconnect pipes from the water flow sensor and the water servo – main
- Remove C Clamp
- Remove the water flow sensor
Step 6: Remove the heat exchanger from the case
- Remove the two set screws on the bottom of the burner
- Remove the two set screws on the top of the case (support bottom of the assembly)
- Copper Heat Exchanger(CU HE), Burner, and Fan will come out in one section. Remove from the unit.
Step 7: Replace CU HE
- Remove ten screws holding the burner to the CU HE
- Separate the burner from the CU HE
Step 8: Remove heat exchanger components from old heat exchanger and put on new heat exchanger
- The gasket on the front of the exhaust box
- Front side: Freeze prevention heater
- Left side: High limit switch and thermistor – heat exchanger
- Replace new O Ring for the thermistor – heat exchanger
- Attach the thermal fuse and six clamps from four sides of the heat exchanger. See four views of the heat exchanger to make sure the thermal fuse is routed correctly
- The end of insulation tube(Black) and the clamp on the left are lined up
Model Include: NR501-OD, NR662-OD
This instructional manual is only intended for use by a qualified service
professional or authorized Noritz 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.
INSTALLATION INSTRUCTION
NR501-OD, NR662-OD Series Heat Exchanger Replacement Procedure
Noritz America Corporation
11160 Grace Avenue, Fountain Valley, CA 92708 Phone 866-766-7489 Fax
714-241-1196