Noritz NRC1111-OD - User Manual

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Overview

Function Description
Important Technical Specifications
Usage Features
Maintenance Features

This document outlines the Heat Exchanger Replacement Procedure for Noritz tankless water heaters, covering various models including NRC1111-OD, NRC1111-DV, NCC1991-OD, NCC1991-DV, NCC1992-DV, NRC111OD(GQ-C3257WX US), NRC111DV(GQ-C3257WX-FF US), NCC199OD(GQ-C3257WZ US), and NCC199DV(GQ-C3257WZ-FF US). The manual emphasizes that any unauthorized use of this manual may result in voiding the warranty.

Function Description

The Noritz tankless water heater is designed to provide on-demand hot water, eliminating the need for a storage tank. This system heats water directly as it flows through a heat exchanger, ensuring a continuous supply of hot water and improved energy efficiency compared to traditional tank-style heaters. The heat exchanger is a critical component responsible for transferring heat from the burner to the water. The replacement procedure detailed in this manual ensures the continued optimal performance and longevity of the water heater by guiding technicians through the process of replacing a worn or damaged heat exchanger.

Important Technical Specifications

The manual does not explicitly list technical specifications such as BTU input, flow rates, or temperature rise for the water heaters. However, it implicitly refers to different models, indicating variations in their design and components. For instance, it distinguishes between "OD" (Outdoor) and "DV" (Direct Vent) models, which typically have different venting requirements and internal configurations. The presence of specific components like "Thermistor - Scale Detection" in certain models (NRC111OD/DV(GQ-C3257WX US) and NCC199OD/DV(GQ-C3257WZ US)) suggests advanced monitoring capabilities for scale buildup, which can impact efficiency and lifespan. The mention of various sensors (Flow Sensor, Water Level Electrode, Thermistor - Heat Exchanger, Thermistor - Cold Water, Thermistor - Hot Water) highlights the sophisticated control system that ensures safe and efficient operation.

Usage Features

While the manual primarily focuses on maintenance, the "Drainage using the Remote Controller" and "Manual Drainage" sections in the initial pages provide insights into user-facing features related to draining the unit. Users can initiate a drain cycle by pressing the "ON/OFF" button, then the "MENU" button, and navigating to the "Drain water now?" option. This feature is crucial for winterizing the unit or performing maintenance. The display shows the water flow meter alarm status, indicating the maximum hot water temperature. The ability to check the water heater's status via the remote controller, including the "Maintenance Monitor Mode" and "Thermistor-ScaleDetection," allows users or technicians to monitor performance and identify potential issues. The display can show the water temperature, and for models with "Thermistor-ScaleDetection," it can show the "Temperature of Thermistor-Scale Detection."

Maintenance Features

The core of this document is the detailed heat exchanger replacement procedure, which serves as a comprehensive maintenance guide. Key maintenance features and steps include:

Front Cover Removal: Disconnecting electrical power, turning off gas and water, and removing screws to access internal components.
Lightning Protection Removal: Removing screws that hold the lightning protection plate and disconnecting additional ground wires.
Wiring Harness Disconnection: Unplugging all wires attached to the wiring harness and the body of the unit, including those for Freeze Prevention Heaters, High Limit Switch, Thermal Fuse, Thermistor - Scale Detection, Fan Motor, Water Flow Sensor, Water Level Electrode, and Thermistor - Heat Exchanger. Specific instructions are provided for different thermistors (Exhaust, Scale Detection).
Flame Rod and Ignition Plug Unplugging: Disconnecting these components.
Exhaust Flue Removal (DV models only): Disconnecting the venting and removing the exhaust flue.
Manifold Plate Removal: Removing screws and detaching the manifold plate, including the inlet pipe.
Pipe Removal: Removing the 1/4" Drain from Copper Heat Exchanger (CU HE) and the Pipe - Flow Sensor to Stainless Steel Heat Exchanger (SS HE) and Water Flow Sensor.
Condensate Container Removal: Removing the metal clamp and hoses connected to the condensate container.
Water Servo Disconnection: Disconnecting pipes from Water Servo - Main and Water Servo - Bypass.
Assembly Removal from Case: Removing screws to detach the SS HE, Copper Heat Exchanger (CU HE), Burner, and Fan Motor as one section.
Heat Exchanger Separation: Separating the Stainless Steel Heat Exchanger (SS HE) from the Copper Heat Exchanger (CU HE) by removing screws and brackets.
Heat Exchanger Replacement: Replacing the SS HE and CU HE, including the burner. This involves replacing old gaskets with new ones.
Thermal Fuse and Clamp Attachment: Attaching thermal fuse clamps on all sides of the CU HE and ensuring proper routing of the thermal fuse.
O-Ring Replacement: Placing new O-rings on the CU HE inlet and outlet.
Reassembly: Reattaching the burner, CU HE, and SS HE, connecting pipes, and securing all components with screws.
Reinstallation of Components: Reinstalling the assembly back into the case, reconnecting the exhaust flue (DV models), water servo pipes, condensate container, flow sensor pipes, and manifold plate.
Wiring Reconnection: Reconnecting all wires to the wiring harness and the unit body, paying close attention to the ignition wire, freeze prevention heaters, and various sensors. Specific warnings are given not to tie the ignition wire with the anchor and to set it behind other wires.
Lightning Protection Reattachment: Attaching the lightning protection plate and ground wires.
Leak Checks: Performing checks for gas leaks and water leaks from various components, including drain valves, inlet water valve, and manifold plate.
Front Cover Replacement: Securing the front cover with screws.
Water Heater Check: Verifying correct operation of the water heater using the remote controller, checking the maintenance monitor mode, and observing water temperature readings. For models with Thermistor-ScaleDetection, checking the temperature of the Thermistor-Scale Detection is crucial.

The manual provides clear diagrams and step-by-step instructions for each procedure, making it an indispensable resource for technicians performing heat exchanger replacements. The emphasis on proper wiring, leak checks, and functional verification ensures that the water heater operates safely and efficiently after maintenance.