Airxcel Suburban ST-60

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Summary

Important Safety Information

General Safety Warnings

Covers essential safety precautions for operation and installation.

Operational Hazard Warnings

Alerts about potential hazards from refueling, submersion, and water temperature.

Operating Safety Information

Gas Leak Detection and Response

Instructions on what to do if a gas odor is detected to prevent fire or explosion.

Operational Safety Alerts

Warnings about ignition, submersion, and venting for safe operation.

Operating Instructions

Sequence of Operation

Step-by-step description of how the water heater initiates and runs.

Using Faucets and Showers

Guidance on operating fixtures for optimal performance and desired temperature.

Shutting Down the Heater

Procedure to safely turn off the on-demand water heater.

Maintenance

Maintenance Cautions and Warnings

Safety advice and warnings regarding repairs, cleaning, and component integrity.

Draining, Storage, and Freeze Protection

Instructions for preparing the unit for storage and preventing freezing damage.

Parts and Service Information

Guidance on obtaining authorized service and parts for the appliance.

Two Year Limited Warranty

Warranty Limitations and Exclusions

Details on what the warranty covers, excludes, and limitations on liability.

Product Problem Resolution

Steps to follow when experiencing issues with the water heater.

Summary

Important Safety Information

General Safety Warnings

Covers essential safety precautions for operation and installation.

Operational Hazard Warnings

Alerts about potential hazards from refueling, submersion, and water temperature.

Operating Safety Information

Gas Leak Detection and Response

Instructions on what to do if a gas odor is detected to prevent fire or explosion.

Operational Safety Alerts

Warnings about ignition, submersion, and venting for safe operation.

Operating Instructions

Sequence of Operation

Step-by-step description of how the water heater initiates and runs.

Using Faucets and Showers

Guidance on operating fixtures for optimal performance and desired temperature.

Shutting Down the Heater

Procedure to safely turn off the on-demand water heater.

Maintenance

Maintenance Cautions and Warnings

Safety advice and warnings regarding repairs, cleaning, and component integrity.

Draining, Storage, and Freeze Protection

Instructions for preparing the unit for storage and preventing freezing damage.

Parts and Service Information

Guidance on obtaining authorized service and parts for the appliance.

Two Year Limited Warranty

Warranty Limitations and Exclusions

Details on what the warranty covers, excludes, and limitations on liability.

Product Problem Resolution

Steps to follow when experiencing issues with the water heater.

This document describes the operation and maintenance of the Suburban On Demand Water Heater, models ST-42 and ST-60, designed for installation in recreational vehicles. This direct vent gas water heater with direct spark ignition provides an endless supply of controlled outlet water temperature when hot water is requested by the user.

Function Description

The water heater operates by sensing water flow when a hot water faucet or other plumbing fixture is opened. Upon sensing flow, it initiates a start-up sequence: the combustion air fan turns on, proper airflow is detected by the control unit, the combustion chamber is purged of any raw gas, and then the burner ignites. Successful burner ignition is confirmed by a flame sense electrode. The approximate time from turning on the faucet to ignition is 7 seconds, which reduces to about 5 seconds once the water heater is maintaining temperature. Hot water begins flowing approximately 3 seconds after ignition, though it may take longer to reach the faucet depending on the length of the hot water lines. The burners remain on until the water flow is shut off, at which point the water heater shuts down and enters a ready state. The blower motor continues to operate for about 20 seconds after the hot water faucet is turned off.

The system is designed to modulate burner output to accurately control the outlet water temperature. Under low flow conditions, a high BTU stage will disengage, and the unit will operate at a very low BTU, conserving propane and improving temperature control. The water heater is factory set to maintain a water temperature of 113°F (45°C), but this can be adjusted by the user between 95°F (35°C) and 131°F (55°C) using the UP or DOWN arrows on the User Control Panel. A child lock feature prevents the outlet water temperature from exceeding 122°F (50°C), which can be overridden by holding the UP arrow for five seconds.

The water heater incorporates several safety features:

Flame Out Protection: Automatically shuts off the gas supply if the flame is extinguished due to low propane gas pressure or burner malfunction.
Low Voltage / High Voltage Protection: Prevents operation if the supplied voltage drops below 10VDC or rises above 17VDC.
Overcurrent Protection: An internal fuse activates and turns off the appliance if a short circuit occurs (>10A).
Flue Fan Monitoring: Shuts off gas to the burner if there is a malfunction in the combustion air fan's airflow.
Hot Water Temperature Protection: A high-temperature switch prevents excessively hot water in case of a malfunction.
Active Freeze Protection: Protects the unit from freezing temperatures by cycling the burner for 5 seconds when the water temperature falls below 41°F (5°C), provided gas and electrical power are available.
High Pressure Protection: A built-in pressure relief valve protects the unit from surges of high water pressure.

Usage Features

To operate the water heater:

Ensure all electric power to the appliance is off.
Turn on the gas supply.
Wait five minutes for gas to clear the area. If gas is smelled, follow the instructions in the OPERATING SAFETY INFORMATION section.
Turn on electrical power to the appliance.
Press the ON button on the User Control Panel.
Open a hot water faucet to a minimum of 0.7 GPM for the unit to operate. If the burner does not light, the system will attempt two more ignitions before locking out. For best results, open the hot water faucet fully until hot water arrives, then reduce flow and mix cold water as needed.
If the water heater runs for more than 20 minutes, it will enter lockout to prevent wasted propane. To reset from lockout, turn the faucet off or press the OFF button on the User Control Panel, then back ON. Initial start-up may require several ignition cycles to purge air from gas lines.
To change the water temperature, use the UP or DOWN arrows on the User Control Panel.

To turn off the water heater:

Press the power button once on the User Control Panel.
Turn off electrical power to the appliance.
Turn off the gas supply.
If storing the vehicle or turning off the heater in freezing temperatures, drain the water heater.

Maintenance Features

Regular maintenance is crucial for safe and efficient operation. All repairs and maintenance should be performed by a dealer or a qualified service technician.

Safety Precautions for Maintenance:

Always label all wires prior to disconnection when servicing controls to prevent improper and dangerous operation due to wiring errors.
No cleaning or adjustment of the burners is permitted. If faulty burner operation is suspected, shut off the appliance immediately and contact a qualified service center.
Periodically inspect the unit for soot, which indicates incomplete combustion. If soot is present, shut down the unit and contact a qualified service person. Check the vent for obstructions and ensure no foreign material prevents airflow. Verify that no flame is present at the burner orifice or burner when the main gas valve is closed (by turning the ON/OFF switch to OFF).
Periodically check wiring and wire connections for damage, fraying, tightness, and compliance with codes.

Draining and Storage Instructions (Winterization): If the RV is to be stored during winter months, the water heater system must be drained to prevent freezing damage.

Turn off electrical power to the water heater.
Shut off the gas supply.
Turn off the pressure pump on the water system.
Open both hot and cold water faucets.
Compressed air (no greater than 40 PSI) is the preferred method for purging the water heater, requiring bypass tees and shut-off valves to isolate the appliance from the plumbing system.
Alternatively, RV NON-TOXIC antifreeze can be added after draining, if recommended by the coach manufacturer.
The system must be refilled with water and all air removed from lines before the unit will re-light.

Descaling Information: Annually, drain the water from the system and flush the heat exchanger with an approved descaling solution.

Pressure Relief Valve: The pressure relief valve is designed to open if water pressure reaches 150 PSI/1034 kPa. If it discharges periodically, it may be due to thermal expansion in a closed water supply system. Contact the water supplier or local plumbing inspector for correction. Do not install any plumbing on the discharge port of the relief valve.

Removing the On Demand Water Heater: