A.O. Smith THR-160 - User Manual

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Installa on Instruc ons and

Use & Care Guide

Keep this manual with the heater for future reference whenever maintenance, adjustment or service is required.

Retain your original receipt as proof of purchase.

Read this manual and the labels on the water heater before you install,

operate, or service it. If you have diﬃ culty following the direc ons, or

aren’t sure you can safely and properly do any of this work yourself:

• Call our Technical Assistance Hotline which is listed on your warranty. We can

help you with installa on, opera ons, troubleshoo ng, or maintenance. Before

you call, write down the model and serial number from the water heater’s ra ng

plate.

• Incorrect installa on, opera on, or service can damage the water heater, your

house and other property, and present risks including ﬁ re, scalding, electric

shock, and explosion, causing serious injury or death.

Residen al Gas

Tankless Water Heater

Residen al On-Demand Gas Tankless Water Heater

(X3™ TECHNOLOGY available on some models)

Do not store or use gasoline or other ﬂ ammable vapors

and liquids in the vicinity of this or any other appliance.

WHAT TO DO IF YOU SMELL GAS

• Do not try to light any appliance.

• Do not touch any electrical switch; do not use any

phone in your building.

• Immediately call your gas supplier from a neighbor’s

phone. Follow the gas supplier’s instruc ons.

• If you cannot reach your gas supplier, call the ﬁ re de-

partment.

Installa on and service must be performed by a qualiﬁ ed

installer, service agency or the gas supplier.

WARNING: If the informa on in these instruc ons

is not followed exactly, a ﬁ re or explosion may

result causing property damage, personal injury or

death.

MODEL:

THR-160, THR-180, THR-199

LOW LEAD

NTENT

100374994_2000628591

December 2023

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This document is an installation and use & care guide for a residential gas tankless water heater, specifically models THR-160, THR-180, and THR-199. The guide emphasizes safety, proper installation, and maintenance to ensure efficient and safe operation.

Function Description:

The device is a residential on-demand gas tankless water heater designed to provide hot water as needed, eliminating the need for a storage tank. It operates by burning natural gas or propane to heat water flowing through a heat exchanger. Some models feature X3™ Technology for scale prevention. The water heater can be installed indoors or outdoors, and in a single unit or as part of a cascade system for greater output. It includes an integrated recirculation pump, which can be configured for dedicated return lines, crossover recirculation, or on-demand activation. The unit is designed to provide hot water for potable uses and can also be integrated into combination potable water heating and space heating systems.

Important Technical Specifications:

Models: THR-160, THR-180, THR-199
Gas Type: Natural Gas (default) or Propane (requires conversion kit)
Minimum Operating Range (BTU/h): 9,000 for all models
Maximum Operating Range (BTU/h):
- THR-160: 160,000
- THR-180: 180,000
- THR-199: 199,000
Gas Connection: 1/2" NPT
Water Connections: 3/4" NPT
Water Pressure: 15 - 150 psi (0.1 - 1 MPa)
Water Flow Rate: 0.26 - 10.5 gpm (1.0 - 39.7 Lpm), Activation min: 0.4 gpm (1.5 Lpm)
Natural Gas Inlet Pressure: Min 3.5" W.C. (0.87 kPa), Max 10.5" W.C. (2.62 kPa)
Propane Inlet Pressure: Min 8.0" W.C. (1.99 kPa), Max 13.0" W.C. (3.24 kPa)
Weight: 104 lbs (47.2 kg)
Dimensions (W x H x D): 16.54 x 41.78 x 16.12 inches (42.00 x 106.13 x 40.96 cm)
Ignition: Electronic Ignition
Electrical Supply: 120V, 50Hz/60Hz, <5A
Water Heater Category: Category IV (for indoor/direct vent installations)
Maximum Pipe Length (Hot Water supply line and Dedicated Return line):
- 3/4" Pipe Diameter: 500 ft (152.4 m)
- 1/2" Pipe Diameter: 200 ft (61 m)
Vent Pipe Materials: Schedule 40 PVC, PVC-DWV, Schedule 40 CPVC, Schedule 40 ABS-DWV, Polypropylene. Cellular core PVC/CPVC or Radel® are prohibited.
Maximum Vent Length (2" venting): 75 ft (22.9 m) for 0 elbows, decreasing with more elbows.
Maximum Vent Length (3" venting): 150 ft (45.7 m) for 0 elbows, decreasing with more elbows.
Pressure Relief Valve: Rated up to 150 psi and maximum BTU/hr of the water heater. Supplied with X3® models, field supplied for M models.

Usage Features:

Temperature Adjustment: Factory set to 120°F (50°C). Can be adjusted using UP/DOWN buttons on the built-in controller. Temperatures above 125°F (52°C) require an additional step (holding SETTING button for 5 seconds).
Unit Conversion Mode: Allows changing temperature units between Fahrenheit (°F) and Celsius (°C), which also converts flow rate units between gallons per minute (gpm) and liters per minute (Lpm).
Configuration Mode (A Mode): Accesses settings like recirculation interval timer, pump turn on/off timers, recirculation mode (No recirculation, Recirculation Active), and recirculation type (Dedicated Return Line, Crossover Valve, On Demand Control - CA Title 24).
Configuration Mode (C Mode): Accesses settings like elevation, gas type (Natural Gas, Propane), and power frequency (60Hz, 50Hz).
Clock Setting: Allows setting the current hour and minute on the built-in controller.
Recirculation Modes:
- Dedicated Return Line: Pump operates to keep water lines warm during user-configured ON periods.
- Crossover Valve Mode: Uses a thermal crossover valve at the furthest fixture to use the cold water line as a return.
- On-Demand Mode: Pump activates via wireless push buttons (requires Remote Recirculation Kit).
Pump Timer Activation: Allows activating Pump Timer 1, Pump Timer 2, both, or turning them off via the TIME button.
Cascade System: Up to 12 heaters can be linked in a Parent/Child configuration for increased output.

Maintenance Features:

Regular Maintenance: Annual checks are recommended by a licensed technician.
Cold-Water/Inlet Filter: Needs to be cleaned periodically to maintain optimum flow.
Venting System: Annual inspection for leaks, corrosion, blockages, or damage.
Area Clearance: Keep the area around the water heater and terminations clear of dust, debris, and combustible materials.
Pressure Relief Valve: Must be manually operated periodically to check for correct operation. Inspect every 2-4 years.
Condensate Drain System: Regular inspection for clogs, proper downward slope, and debris in the condensate trap. If a neutralizer is installed, check the pH and replace the neutralizer cartridge if pH drops below 6.0.
Freeze Protection System: The unit has heating blocks and auto-fires to prevent freezing damage to internal components, but external pipes require insulation. A Cartridge Freeze Protection Kit is available for external cartridges.
Unit Draining: Instructions are provided for draining the unit, especially if it will not be used for a long period or if power is lost during freezing conditions. This involves closing gas and water valves, disconnecting power, opening hot water taps, and draining the X3® or Bypass Cartridge.
Error Codes: The water heater has self-diagnostic functions that display error codes (e.g., E002 for Hi-Limit Switches, E036 for Flame Failure) on the built-in controller for troubleshooting. A fault analysis table provides procedures to address these errors.