Once the water heater has been installed according to the instructions and the water supply is turned on, you should hear a series of clicks, followed by the sound of the burner igniting. If you do not hear these sounds, please refer to the troubleshooting steps outlined below.

• Ensure the ON/OFF switch at the bottom of the water heater is in the ON position.
• Ensure the 2 “D” batteries are in working condition and inserted properly in the correct position. If you're using the 12-volt ignition feature, ensure the alligator clip’s 12-volt connector is fully inserted into the water heater’s 12-volt port to establish a proper connection. Also, confirm that the 12-volt power source (e.g., a 12-volt battery) is charged and functioning correctly.
• Ensure the incoming water hose is connected to the water inlet of the water heater and the outgoing water hose (shower set) is connected to the water outlet. The water heater will not ignite if the connections are reversed.
• The water heater must be mounted vertically (on a wall) using the unit's mounting brackets, not the carrying handle. For example, if the unit is slightly tilted, ignition will not occur as a safety measure.
• Check for debris in the water heater’s water inlet. The presence of debris in the water inlet screen may affect the incoming water pressure, which could prevent the flame from igniting.
• Verify the water pressure, as insufficient pressure is one of the most common reasons for ignition failure. The water heater requires a minimum sustained pressure of 10 PSI to ignite the burner. For reference, municipal water systems typically provide around 60 PSI, and most water pumps operate within the 40–60 PSI range.
  IMPORTANT: Please note that while most water pumps provide adequate PSI, ignition issues often result from using water hoses with an incorrect diameter (e.g., 5/8", 3/4"). To ensure proper pressure and avoid ignition failure, always use a 1/2" diameter hose from the water source to the pump and from the pump to the water heater.
• If using a water pump for water pressure, try connecting the water heater to municipal water instead. Water pumps can sometimes provide mixed results based on the specifications and the connection configuration between the pump and water heater. Connecting the water heater to a different water source is the best way to determine if the problem is due to a configuration issue or a defective water heater.
• Check for any possible disconnected wires inside the water heater, which can sometimes occur during shipping. If a wire is disconnected, there will be no audible clicking sound (similar to a BBQ) from the ignition pins. To check the wires, ensure the gas supply is turned off, pull off the gas and water regulator knobs, and remove the screws holding the front panel in place. Remove the front panel and locate the disconnected wires toward the bottom of the water heater.
If you need assistance removing the front panel of your unit, please visit our YouTube channel for step-by-step video instructions Click here

For additional support, please contact Onsen at: support@onsenproducts.ca or 800-996-5559.

If the water heater is not producing hot water, it indicates that the flame in the heat exchanger is not igniting. If you hear a clicking sound—similar to that of a BBQ igniter—this confirms that the electrical ignition system is functioning properly. In this case, the issue is likely related to the gas supply.
• Ensure the propane tank is not depleted.
• Check for debris in the water heater’s gas inlet and the opening of the gas regulator hose connected to the inlet. The presence of debris may prevent gas from flowing normally into the water heater.
• If the solenoid is not opening as it should, it will prevent gas from reaching the burner. You can easily check whether the solenoid is functioning by listening to the sounds the water heater makes during the ignition sequence. A properly working solenoid emits a distinct metallic click, typically heard toward the end of the series of ignition clicks (similar to the sound of a BBQ igniter).
• Wind gusts may be preventing the burner from igniting properly. Make sure to protect the water heater from the wind by placing it ideally in a sheltered spot, such as between two walls.

For additional support, please contact Onsen at: support@onsenproducts.ca or 800-996-5559.

Here are some of the most common reasons why the water heater might shut off at different times after being turned on:

• An insufficient water flow and pressure prevent the burner from keeping the flame lit, or significant fluctuations in water flow and pressure can cause the flame to go out.
  Make sure to connect the water heater to a steady water pressure source between 10 and 80 PSI. Sudden drops in water pressure caused by a water pump or a municipal water source may lead to the flame randomly extinguishing. Connecting the water heater to an alternative water pressure source is the most effective way to determine the root cause of the problem: inadequate water pressure or installation.
  IMPORTANT: Please note that while most water pumps provide adequate pressure, ignition issues are often caused by using garden hoses with a large diameter (e.g., 5/8", 3/4"). To ensure proper pressure and prevent ignition failures, always use a 1/2" diameter hose between the water source and the pump, as well as between the pump and the water heater. Additionally, avoid setups where water has to be drawn or pushed over long distances, and avoid steep slopes in hose positioning between the water source and the outlet (showerhead). It is recommended to keep hose runs to a horizontal distance not exceeding 25 feet.
• When the installation includes a cold-water mixing line to blend cooler water with the hot water produced by the heater, ensure that your water-pressure system can deliver sufficient flow and pressure to supply both the hot and cold lines simultaneously. If the system cannot maintain adequate pressure, the heater may shut off unexpectedly due to a pressure drop when both lines are in use. To prevent this issue, you may need to install a second water pump dedicated to the cold-water line to ensure consistent and balanced water flow.
• The water heater is equipped with a temperature sensor that, as a safety measure, automatically shuts off the flame when the water temperature reaches 50 °C / 122 °F (5L model) or 60 °C / 140 °F (7L and 10L models). To restart the unit, turn the showerhead button to the OFF position to stop the water flow, then switch it back to the ON position to restore the flow. The water heater will then restart normally.
• Gusts of wind can prevent the burner from keeping the flame lit. Make sure to protect the water heater from the wind by ideally placing it in a sheltered area, such as between two walls or partitions.

For additional support, please contact Onsen at: support@onsenproducts.ca or 800-996-5559.

When the water temperature at the outlet is too high for a comfortable shower, even with the gas control set to minimum and the water flow at maximum, this generally means that the incoming water is not cold enough and/or the water flow through the plumbing is too low.
This issue is much more common with the Onsen 10L model due to its high heating capacity.

To address this situation, here are a few solutions to help reduce the outlet water temperature:

• Add a cold-water line to mix cooler water with the hot water coming from the heater.
• Improve the water pressure system to increase the water flow feeding the heater (e.g., by installing a higher-flow pump).
• Install a ball valve on the gas line to reduce the amount of gas circulating to the burner.
Note that it's always best to choose the water heater model according to the source water temperature. For example, in summer, when the water is around 15–20 °C (59–68 °F), the 5L model is usually sufficient for a comfortable shower. However, during colder seasons, when the water temperature drops to between 4–10 °C (39–50 °F), it’s better to opt for the 7L or 10L model.